Re: [bolger] Re: Plywood Again??? Forget Marine Ply!!!
That's exactly what I did. I don't know how thick their skins are; but If I
were in a position to order a boat build that way I'd insist on a filling of
the slots at leats with more foam.
I really don't claim or want to argue my point beyond the fact that I looked
at it in a very amateurish way; but decided I didn't trust this method; or
voids and gaps between skin sheets in a composite.
Now no matter how wrong I might be; I'm never going to be particular happy
in a boat that has this issue; so I avoid it.
Hajo
On Jan 8, 2008 11:31 PM, Stefan Probst <stefan.probst@opticom.v-nam.net>
wrote:
were in a position to order a boat build that way I'd insist on a filling of
the slots at leats with more foam.
I really don't claim or want to argue my point beyond the fact that I looked
at it in a very amateurish way; but decided I didn't trust this method; or
voids and gaps between skin sheets in a composite.
Now no matter how wrong I might be; I'm never going to be particular happy
in a boat that has this issue; so I avoid it.
Hajo
On Jan 8, 2008 11:31 PM, Stefan Probst <stefan.probst@opticom.v-nam.net>
wrote:
> --- "Hajo Smulders" <hajosmulders@...> wrote:[Non-text portions of this message have been removed]
> > Slots were probably up to an half an inch wide in a 2 inch piece
> > of foam at the 'open side' of the curve. These were gaps; not voids.
>
> Something like on
>http://www.amateurboatbuilding.com/articles/howto/foam_sandwich/index.html
> under the headline "Wide foam sheet planking"?
>
> Seems to be ok there.
>
> Stefan
>
>
>
--- "Hajo Smulders" <hajosmulders@...> wrote:
http://www.amateurboatbuilding.com/articles/howto/foam_sandwich/index.html
under the headline "Wide foam sheet planking"?
Seems to be ok there.
Stefan
> Slots were probably up to an half an inch wide in a 2 inch pieceSomething like on
> of foam at the 'open side' of the curve. These were gaps; not voids.
http://www.amateurboatbuilding.com/articles/howto/foam_sandwich/index.html
under the headline "Wide foam sheet planking"?
Seems to be ok there.
Stefan
--- "Hajo Smulders" <hajosmulders@...> wrote:
The side where the weight was put on(?).
So a thin skin of less than 1 mm thickness (Epoxy with some GF?) had
to cover 10 mm gaps. At the outside, i.e. the side where the load is,
the skin would be compressed, but over those gaps the skin was not
held in place because there was no foam where it would be glued to.
Means: the skin could buckle inwards or outwards.
If the skins would be say 4 mm (like doorskin) ply, and the gaps only
the same width or less, then there should be no major problem, no?
Why I am asking: Supposed you form the inside of a hull first, then
cut stripes of foam and glue them to the inside, then there too would
be gaps, but they can be kept small.... As long as the outer skin
cannot bend into the gaps (or outward), then this should be ok ....
Stefan
> Slots were probably up to an half an inch wideThose were cuts on the outside (i.e. larger radius), no?
> in a 2 inch piece of foam at the 'open side' of the curve.
> These were gaps; not voids.
The side where the weight was put on(?).
So a thin skin of less than 1 mm thickness (Epoxy with some GF?) had
to cover 10 mm gaps. At the outside, i.e. the side where the load is,
the skin would be compressed, but over those gaps the skin was not
held in place because there was no foam where it would be glued to.
Means: the skin could buckle inwards or outwards.
If the skins would be say 4 mm (like doorskin) ply, and the gaps only
the same width or less, then there should be no major problem, no?
Why I am asking: Supposed you form the inside of a hull first, then
cut stripes of foam and glue them to the inside, then there too would
be gaps, but they can be kept small.... As long as the outer skin
cannot bend into the gaps (or outward), then this should be ok ....
> foam pieces were perpendicular on sawhorses (1' sectionCheers,
> resting on sawhorse; 4' across)
> I only did one curved section which I tested from the outside.
> It buckled so quickly that I didn't test further.
Stefan
> After seeing your pictures, I cannot help but wonder if the rocks mightWell, it occurred ten years ago and my memory has faded. Yes, I agree
> not have made a hole in the boat if the entire hull had been sheathed
> in glass -- especially on the inside -- which would have put that
> inside layer of glass into tension and therefore resisted most of the
> energy of those rocks trying to puncture the hull.
>
> You were there, what do you think?
that sheathing the bilge panels in glass would have allowed the cloth
to act in tension, like a drum head or trampoline. The keel panel was
sheathed, and it did not break.
http://hallman.org/bolger/roar/boulder.jpg
Ignore the holes for a moment and look at the seams.
A key thing to notice is how the taped seam separated (visible in the
above photo). The exact zone of failure was in the wood immediately
adjacent to the tape and not in the tape itself. And more, it
failed on the side of the taped seam where wood was pulling away, and
not on the side of the seam where the tape was bearing on wood. Wood
fibers in compression are much stronger than wood fibers in tension.
This tells me that sheathing the outside (glass bearing on wood) would
have provided more strength than sheathing the inside (glass pulling
away from wood).
That test proved that fiberglass that bears on wood is much stronger
that fiberglass that pulls away from wood.
no numbers; top of my head: i had a flood loss a few years ago thanks to
Hurricane (Tropical storm once it got to my house) Ivan.
Slots were probably up to an half an inch wide in a 2 inch piece of foam at
the 'open side' of the curve. These were gaps; not voids.
I didn't fill the slots with an epoxy /filler balloon filling. (I know that
would be super strong; but would defeat the purpose of this construction
method for light weight.)
foam pieces were perpendicular on sawhorses (1' section resting on sawhorse;
4' across)
I only did one curved section which I tested from the outside. It buckled so
quickly that I didn't test further.
My testing (For this particular boat; an international moth) quickly pointed
to a thin foam shell (Say 1/2 inch) and carbon fiber skins.
I'm sorry I don't have more on this; This was just a weekend messing around
with materials in the backyard. (Which is kind of fun; drink beer with your
mates; fill a big drum with water and wait in anticipation till the thing
buckles. I'm easy to please...)
Hajo
On Jan 7, 2008 11:56 PM, Stefan Probst <stefan.probst@opticom.v-nam.net>
wrote:
--------------------------------------------------------------------------------------------------
Q: How many women does it take to screw in a light bulb?
A: That's "womyn" with a Y, and it's not funny!
[Non-text portions of this message have been removed]
Hurricane (Tropical storm once it got to my house) Ivan.
Slots were probably up to an half an inch wide in a 2 inch piece of foam at
the 'open side' of the curve. These were gaps; not voids.
I didn't fill the slots with an epoxy /filler balloon filling. (I know that
would be super strong; but would defeat the purpose of this construction
method for light weight.)
foam pieces were perpendicular on sawhorses (1' section resting on sawhorse;
4' across)
I only did one curved section which I tested from the outside. It buckled so
quickly that I didn't test further.
My testing (For this particular boat; an international moth) quickly pointed
to a thin foam shell (Say 1/2 inch) and carbon fiber skins.
I'm sorry I don't have more on this; This was just a weekend messing around
with materials in the backyard. (Which is kind of fun; drink beer with your
mates; fill a big drum with water and wait in anticipation till the thing
buckles. I'm easy to please...)
Hajo
On Jan 7, 2008 11:56 PM, Stefan Probst <stefan.probst@opticom.v-nam.net>
wrote:
> Dear Hajo,--
>
> I love thos kind of home-grown tests.
> Surely would be interesting also, if you could publish numbers.
>
> --- "Hajo Smulders" <hajosmulders@...> wrote:
> > The testing was done as follows; since I only cared about relative
> > strengths:
> > I would get a piece of foam 4 feet by a foot;
> > skin both sides with epoxy;
> > put the piece between two sawhorses;
> > put a big drum on it and start filling it;
> > last one to buckle wins.
> > Now the important part that i metnioned was that voids in foam
> > (where cuts were made in order to make certain curves)
> > were the areas of buckling. They buckled waaaay before a piece
> > of foam without voids.
>
> So, if I understand this right:
> You were cutting "slots" perpendicular to the skins into the foam,
> then bent the foam accordingly, and skinned the sides with epoxy.
> So it was more "gaps", not "voids" like in plywood (?).
>
> How wide were the gaps, relative to the foam thickness?
> Did you apply only epoxy, or also a layer of GF?
>
> When you placed the curved panels onto the sawhorses, how did you do?
> Where the saw horses parallel to the bend (i.e. the panels rested with
> the full 1' width on the horses), or were they perpendicular to the
> bend (i.e. the panels rested on the horses only on a small point)?
>
> Did you place the weight at the outside of the bend (i.e. shell
> effect), or at the inside?
>
> > Secondary note: The cost of wood is not that much on all
> > the costs of a boat combined so I would spend it there;
>
> As I always try to repeat: cost is not an universal constant.
> If the particular material is not locally available, and you have to
> add international shipping, customs, etc., then the balance of cost
> quickly shifts to another side ....
>
> Cheers,
> Stefan
>
>
>
--------------------------------------------------------------------------------------------------
Q: How many women does it take to screw in a light bulb?
A: That's "womyn" with a Y, and it's not funny!
[Non-text portions of this message have been removed]
Weight and speed of excelaration it could have been a flat slab and
squash. Beaching on a sandy beach can break some boats if built to
light for the load and or size.
Jon
--- Inbolger@yahoogroups.com, "Stefan Probst" <stefan.probst@...>
wrote:
squash. Beaching on a sandy beach can break some boats if built to
light for the load and or size.
Jon
--- Inbolger@yahoogroups.com, "Stefan Probst" <stefan.probst@...>
wrote:
>ply.
> --- Kristine Bennett <femmpaws@> wrote:
> >
> > When it come to hitting rock and logs you are point loading
> > the hull and the stress loads go up extremely fast.
>
> Well, this is true, if the rock falls with an edge/point facing the
> Assume that it falls with a wide side facing the ply, or such that
> several points, or even areas touch the rock after the first
> deformation of the ply, then things look differently.
>
> Stefan
>
--- Kristine Bennett <femmpaws@...> wrote:
Assume that it falls with a wide side facing the ply, or such that
several points, or even areas touch the rock after the first
deformation of the ply, then things look differently.
Stefan
>Well, this is true, if the rock falls with an edge/point facing the ply.
> When it come to hitting rock and logs you are point loading
> the hull and the stress loads go up extremely fast.
Assume that it falls with a wide side facing the ply, or such that
several points, or even areas touch the rock after the first
deformation of the ply, then things look differently.
Stefan
Dear Hajo,
I love thos kind of home-grown tests.
Surely would be interesting also, if you could publish numbers.
--- "Hajo Smulders" <hajosmulders@...> wrote:
You were cutting "slots" perpendicular to the skins into the foam,
then bent the foam accordingly, and skinned the sides with epoxy.
So it was more "gaps", not "voids" like in plywood (?).
How wide were the gaps, relative to the foam thickness?
Did you apply only epoxy, or also a layer of GF?
When you placed the curved panels onto the sawhorses, how did you do?
Where the saw horses parallel to the bend (i.e. the panels rested with
the full 1' width on the horses), or were they perpendicular to the
bend (i.e. the panels rested on the horses only on a small point)?
Did you place the weight at the outside of the bend (i.e. shell
effect), or at the inside?
If the particular material is not locally available, and you have to
add international shipping, customs, etc., then the balance of cost
quickly shifts to another side ....
Cheers,
Stefan
I love thos kind of home-grown tests.
Surely would be interesting also, if you could publish numbers.
--- "Hajo Smulders" <hajosmulders@...> wrote:
> The testing was done as follows; since I only cared about relativeSo, if I understand this right:
> strengths:
> I would get a piece of foam 4 feet by a foot;
> skin both sides with epoxy;
> put the piece between two sawhorses;
> put a big drum on it and start filling it;
> last one to buckle wins.
> Now the important part that i metnioned was that voids in foam
> (where cuts were made in order to make certain curves)
> were the areas of buckling. They buckled waaaay before a piece
> of foam without voids.
You were cutting "slots" perpendicular to the skins into the foam,
then bent the foam accordingly, and skinned the sides with epoxy.
So it was more "gaps", not "voids" like in plywood (?).
How wide were the gaps, relative to the foam thickness?
Did you apply only epoxy, or also a layer of GF?
When you placed the curved panels onto the sawhorses, how did you do?
Where the saw horses parallel to the bend (i.e. the panels rested with
the full 1' width on the horses), or were they perpendicular to the
bend (i.e. the panels rested on the horses only on a small point)?
Did you place the weight at the outside of the bend (i.e. shell
effect), or at the inside?
> Secondary note: The cost of wood is not that much on allAs I always try to repeat: cost is not an universal constant.
> the costs of a boat combined so I would spend it there;
If the particular material is not locally available, and you have to
add international shipping, customs, etc., then the balance of cost
quickly shifts to another side ....
Cheers,
Stefan
Hmm I must have missed something. When it come to hitting rock and logs you are point loadind the hull and the stress loads go up extremely fast. It's also known as shock loading. .
So it may not be the woods fault for braking other then a concentrated load that the hull skin could not take. And once a point failure starts it cascades from there.
Krissie
Kenneth Grome <bagacayboatworks@...> wrote: Hi Bruce,
Ater seeing your pictures, I cannot help but wonder if the rocks might
not have made a hole in the boat if the entire hull had been sheathed
in glass -- especially on the inside -- which would have put that
inside layer of glass into tension and therefore resisted most of the
energy of those rocks trying to puncture the hull.
You were there, what do you think?
Sincerely,
Ken Grome
Bagacay Boatworks
www.bagacayboatworks.com
_
---------------------------------
Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.
[Non-text portions of this message have been removed]
So it may not be the woods fault for braking other then a concentrated load that the hull skin could not take. And once a point failure starts it cascades from there.
Krissie
Kenneth Grome <bagacayboatworks@...> wrote: Hi Bruce,
Ater seeing your pictures, I cannot help but wonder if the rocks might
not have made a hole in the boat if the entire hull had been sheathed
in glass -- especially on the inside -- which would have put that
inside layer of glass into tension and therefore resisted most of the
energy of those rocks trying to puncture the hull.
You were there, what do you think?
Sincerely,
Ken Grome
Bagacay Boatworks
www.bagacayboatworks.com
> Also, looking past the puncture holes, it was--
> very revealing to notice the failure mode of
> the taped seams. (Failure occurred due to wood
> fiber separation, tensile.)
_
---------------------------------
Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.
[Non-text portions of this message have been removed]
There are different kinds of voids from a small knot missing to
inerplys 3/8" apart in ply with 3 layers. A few small knotes may not be
a problem the 3/8" could be glass or no glass. Take 1/4" 3ply a 1/4"
gap in the iner ply is like perferating the paper in a roll of paper
towels if it bangs something it will break. Unless it is a big boat it
will be scraped and no one hears about it. Yes it is important and any
one that thinks it isn't that builds boats for others better have good
insurance.
Jon
inerplys 3/8" apart in ply with 3 layers. A few small knotes may not be
a problem the 3/8" could be glass or no glass. Take 1/4" 3ply a 1/4"
gap in the iner ply is like perferating the paper in a roll of paper
towels if it bangs something it will break. Unless it is a big boat it
will be scraped and no one hears about it. Yes it is important and any
one that thinks it isn't that builds boats for others better have good
insurance.
Jon
Hi Bruce,
Ater seeing your pictures, I cannot help but wonder if the rocks might
not have made a hole in the boat if the entire hull had been sheathed
in glass -- especially on the inside -- which would have put that
inside layer of glass into tension and therefore resisted most of the
energy of those rocks trying to puncture the hull.
You were there, what do you think?
Sincerely,
Ken Grome
Bagacay Boatworks
www.bagacayboatworks.com
Ater seeing your pictures, I cannot help but wonder if the rocks might
not have made a hole in the boat if the entire hull had been sheathed
in glass -- especially on the inside -- which would have put that
inside layer of glass into tension and therefore resisted most of the
energy of those rocks trying to puncture the hull.
You were there, what do you think?
Sincerely,
Ken Grome
Bagacay Boatworks
www.bagacayboatworks.com
> Also, looking past the puncture holes, it was--
> very revealing to notice the failure mode of
> the taped seams. (Failure occurred due to wood
> fiber separation, tensile.)
> And if you could weld 1/32" steel sheet without epic levels of distortion,My point is that the 1/32" epoxied fiberglass cloth would be sufficient.
> it would probably make a mighty fine rowboat. :)
If you removed the plywood entirely, the boat could still float, like
a skinned kayak.
> The overall strength of aYes, and that strength comes from not from the skin, but from the
> boat does come from its performance as a beam...
whole integrated assembly, with the keel, bulkheads, top deck, (and
with open boats) the gunnels providing critical beam strength for the
entire hull form.
> but the individual panelsIf you are speaking of the individual skin panels, I think the best
> are still loaded in bending, torsion, shear, and compression,
analogy is a drum head or a trampoline.
With shells, like fiberglassed plywood panel boats, the major stress
involved (while afloat) is mostly simple tension.
Shear stress comes into play for skin punctures.
On Jan 7, 2008 10:57 AM, Bruce Hallman <bruce@...> wrote:
it would probably make a mighty fine rowboat. :) The overall strength of a
boat does come from its performance as a beam... but the individual panels
are still loaded in bending, torsion, shear, and compression, and still have
to perform well there for the boat as a whole to perform well, structurally.
-p
[Non-text portions of this message have been removed]
>And if you could weld 1/32" steel sheet without epic levels of distortion,
> A 700 foot oil tanker with 1 1/2" thick skin equates to having a 16
> foot rowboat with 1/32" thick skin.
>
it would probably make a mighty fine rowboat. :) The overall strength of a
boat does come from its performance as a beam... but the individual panels
are still loaded in bending, torsion, shear, and compression, and still have
to perform well there for the boat as a whole to perform well, structurally.
-p
[Non-text portions of this message have been removed]
> put the piece between two sawhorses;That is a bending test.
> put a big drum on it and start filling it;
> last one to buckle wins.
Most boat hulls rely on 'shell effect' for strength.
Consider this, very thin skins give shell effect.
For instance, skinned kayaks, or the Platt Montfort geodesics.
Even oil tankers, proportionately having a very thin steel skin shell.
http://www.150.si.edu/siarch/handbook/hbpics/106cor.jpg
http://home.rdbriggs.com/images/blue_sm.gif
A 700 foot oil tanker with 1 1/2" thick skin equates to having a 16
foot rowboat with 1/32" thick skin.
Don't mean to start some type of fight; However I take big exception to the
statement that most boats are overbuild. Time and time again (Not just
Fastnet or Sidney-Hobart) boats get caught in unexpected weather. If there
is one lesson of the past 30 years it is that boats are becoming seriously
underbuilt once caught in heavy weather. Thanks to superior weather
forecasting; GPS naviagtion; communications gear etc... less and less people
get caught in gales; However when it does happen modern boats get stays and
blocks ripped out of decks;
When boats were a lot heavier you could sail pretty much any 35 footer and
larger in a gale by heaving to (I believe that's what you call it in
english; not my native tongue: Sorry...) IE: put a storm jib on backwards;
put up a storm main sail for a reach: your boat will try to round into the
wind; the jib will push it back... (One of the safest ways to ride out a
gale)
You buy a basic 35 footer cruiser nowadays and they are frankly not build to
stand such abuse.
Note: this is an opinion of mine; So I have no hard data to back this up
except a gut feeling. I'll tell you though; I'd rather cross the southern
ocean in a boat made out of boilerplate than a composite.
Hajo
statement that most boats are overbuild. Time and time again (Not just
Fastnet or Sidney-Hobart) boats get caught in unexpected weather. If there
is one lesson of the past 30 years it is that boats are becoming seriously
underbuilt once caught in heavy weather. Thanks to superior weather
forecasting; GPS naviagtion; communications gear etc... less and less people
get caught in gales; However when it does happen modern boats get stays and
blocks ripped out of decks;
When boats were a lot heavier you could sail pretty much any 35 footer and
larger in a gale by heaving to (I believe that's what you call it in
english; not my native tongue: Sorry...) IE: put a storm jib on backwards;
put up a storm main sail for a reach: your boat will try to round into the
wind; the jib will push it back... (One of the safest ways to ride out a
gale)
You buy a basic 35 footer cruiser nowadays and they are frankly not build to
stand such abuse.
Note: this is an opinion of mine; So I have no hard data to back this up
except a gut feeling. I'll tell you though; I'd rather cross the southern
ocean in a boat made out of boilerplate than a composite.
Hajo
On Jan 7, 2008 1:18 PM, Pierce Nichols <rocketgeek@...> wrote:
> On Jan 7, 2008 8:28 AM, <BllFs6@...<BllFs6%40aol.com>> wrote:
>
> >
> > In a message dated 1/7/2008 9:53:07 AM Central Standard Time,
> >rocketgeek@...<rocketgeek%40gmail.com> writes:
> >
> > Since the highest stress on the panel is now much larger
> > for a given load on the panel, and the panel will start to fail as soon
> > as
> > any part of it goes past the failure stress of the material, the entire
> > panel will fail at a much lower load than it would without the void
> >
> >
> >
> >
> > I disagree....
> >
> > Unless your boat is designed to barely not break apart....this is more
> > theorectical than practical....
> >
>
> I was responding to a pretty specific question concerning composite
> panels.
> Fact is, mst boats are massively overbuilt, so that even a signficant
> reduction in strength or fatigue life in one part of the structure is
> unlikely to result in complete structural failure. My impression is that
> the
> formation of rot pockets due to water being wicked into voids prior to
> sealing is a more serious concern.
>
> All this near perfect versus not nearly so perfect only buys you a SMALL
> > range out of a LARGE range of conditions under which the near perfect
> one
> > saves
> > your butt.....
>
> You forgot about fatigue, which is the other joker in that particular
> deck...
>
> > Given how varied sea conditions are.....boat
> > conditions...waves.....georgraphy....level of boat
> construction...skipper
> > skills....etc etc.....in my
> > opinion focusing on perfection on one small part of the total equation
> > that only
> > makes the difference between good and bad over a small range of the
> total
> > is
> > wasted effort.....
>
> Here's the thing: where I live (Southern CA), void-free imported plywood
> (BS6566 Meranti) isn't all that much more expensive than domestic A/C fir
> exterior, and is still less expensive than the epoxy required to seal the
> whole boat. The cost savings just aren't that large, especially given the
> extra difficulties of finishing fir as opposed to the tropical stuff.
>
> -p
>
> [Non-text portions of this message have been removed]
>
>
>
--
--------------------------------------------------------------------------------------------------
Q: How many women does it take to screw in a light bulb?
A: That's "womyn" with a Y, and it's not funny!
[Non-text portions of this message have been removed]
In a message dated 1/7/2008 12:18:39 PM Central Standard Time,
rocketgeek@...writes:
Here's the thing: where I live (Southern CA), void-free imported plywood
(BS6566 Meranti) isn't all that much more expensive than domestic A/C fir
exterior, and is still less expensive than the epoxy required to seal the
whole boat. The cost savings just aren't that large, especially given the
extra difficulties of finishing fir as opposed to the tropical stuff
In that case I'd say go for it...
Personally I am well known for gold plating a terd...and fixating on getting
EVERYTHING perfect.........but I am trying to reform
If I was building a boat.....if getting marine grade void free plywood was
easy and wouldnt break the bank....I have no doubt I'd use that stuff in a
heart beat.....but if not I'd use the "crappy" stuff....and I'd probably be
fretting the whole time about it as well....ala Adrian Monk....and probably
chanting to myself "it just doesnt matter...it just doesnt matter...it just doesnt
matter"....
However...for many folks....getting the good stuff seems to be almost
impossible at any price...or if even if they can get it, the cost is prohibitive....
Those are the folks I hope to console....
Even IFF your plywood has voids ....statistically its probably easier time
and money wise to deal with the problems that MAY arise from them...if and
when they do arise.......than to expend the effort to insure they dont exist in
the first place....
take care
Blll
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
[Non-text portions of this message have been removed]
rocketgeek@...writes:
Here's the thing: where I live (Southern CA), void-free imported plywood
(BS6566 Meranti) isn't all that much more expensive than domestic A/C fir
exterior, and is still less expensive than the epoxy required to seal the
whole boat. The cost savings just aren't that large, especially given the
extra difficulties of finishing fir as opposed to the tropical stuff
In that case I'd say go for it...
Personally I am well known for gold plating a terd...and fixating on getting
EVERYTHING perfect.........but I am trying to reform
If I was building a boat.....if getting marine grade void free plywood was
easy and wouldnt break the bank....I have no doubt I'd use that stuff in a
heart beat.....but if not I'd use the "crappy" stuff....and I'd probably be
fretting the whole time about it as well....ala Adrian Monk....and probably
chanting to myself "it just doesnt matter...it just doesnt matter...it just doesnt
matter"....
However...for many folks....getting the good stuff seems to be almost
impossible at any price...or if even if they can get it, the cost is prohibitive....
Those are the folks I hope to console....
Even IFF your plywood has voids ....statistically its probably easier time
and money wise to deal with the problems that MAY arise from them...if and
when they do arise.......than to expend the effort to insure they dont exist in
the first place....
take care
Blll
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
[Non-text portions of this message have been removed]
On the testing I did:
This is a few years ago when I was looking into building an International
Moth.
(Never got build; I will one day though; these things are cool!)
I experimented with fiberglass on foam; carbon fiber on foam; Kevlar on foam
I tried different foams; (Some of the cheaper home-depot stuff included; did
you know their pink foam is quite impressive for boat skins???)
The testing was done as follows; since I only cared about relative
strengths:
I would get a piece of foam 4 feet by a foot; skin both sides with epoxy;
put the piece between two sawhorses; put a big drum on it and start filling
it; last one to buckle wins.
Now the important part that i metnioned was that voids in foam (where cuts
were made in order to make certain curves) were the areas of buckling. They
buckled waaaay before a piece of foam without voids.
Now my thinking might be wrong were plywood is concerned; especially five
ply wood; however I've become very weary of voids; maybe unduly so.
Secondary note: The cost of wood is not that much on all the costs of a boat
combined so I would spend it there; (Also brand name epoxy...) everything
else can be 'upgraded' down the road.
Hajo
--
--------------------------------------------------------------------------------------------------
Q: How many women does it take to screw in a light bulb?
A: That's "womyn" with a Y, and it's not funny!
[Non-text portions of this message have been removed]
This is a few years ago when I was looking into building an International
Moth.
(Never got build; I will one day though; these things are cool!)
I experimented with fiberglass on foam; carbon fiber on foam; Kevlar on foam
I tried different foams; (Some of the cheaper home-depot stuff included; did
you know their pink foam is quite impressive for boat skins???)
The testing was done as follows; since I only cared about relative
strengths:
I would get a piece of foam 4 feet by a foot; skin both sides with epoxy;
put the piece between two sawhorses; put a big drum on it and start filling
it; last one to buckle wins.
Now the important part that i metnioned was that voids in foam (where cuts
were made in order to make certain curves) were the areas of buckling. They
buckled waaaay before a piece of foam without voids.
Now my thinking might be wrong were plywood is concerned; especially five
ply wood; however I've become very weary of voids; maybe unduly so.
Secondary note: The cost of wood is not that much on all the costs of a boat
combined so I would spend it there; (Also brand name epoxy...) everything
else can be 'upgraded' down the road.
Hajo
--
--------------------------------------------------------------------------------------------------
Q: How many women does it take to screw in a light bulb?
A: That's "womyn" with a Y, and it's not funny!
[Non-text portions of this message have been removed]
On Jan 7, 2008 8:28 AM, <BllFs6@...> wrote:
Fact is, mst boats are massively overbuilt, so that even a signficant
reduction in strength or fatigue life in one part of the structure is
unlikely to result in complete structural failure. My impression is that the
formation of rot pockets due to water being wicked into voids prior to
sealing is a more serious concern.
All this near perfect versus not nearly so perfect only buys you a SMALL
deck...
(BS6566 Meranti) isn't all that much more expensive than domestic A/C fir
exterior, and is still less expensive than the epoxy required to seal the
whole boat. The cost savings just aren't that large, especially given the
extra difficulties of finishing fir as opposed to the tropical stuff.
-p
[Non-text portions of this message have been removed]
>I was responding to a pretty specific question concerning composite panels.
> In a message dated 1/7/2008 9:53:07 AM Central Standard Time,
>rocketgeek@...writes:
>
> Since the highest stress on the panel is now much larger
> for a given load on the panel, and the panel will start to fail as soon
> as
> any part of it goes past the failure stress of the material, the entire
> panel will fail at a much lower load than it would without the void
>
>
>
>
> I disagree....
>
> Unless your boat is designed to barely not break apart....this is more
> theorectical than practical....
>
Fact is, mst boats are massively overbuilt, so that even a signficant
reduction in strength or fatigue life in one part of the structure is
unlikely to result in complete structural failure. My impression is that the
formation of rot pockets due to water being wicked into voids prior to
sealing is a more serious concern.
All this near perfect versus not nearly so perfect only buys you a SMALL
> range out of a LARGE range of conditions under which the near perfect oneYou forgot about fatigue, which is the other joker in that particular
> saves
> your butt.....
deck...
> Given how varied sea conditions are.....boatHere's the thing: where I live (Southern CA), void-free imported plywood
> conditions...waves.....georgraphy....level of boat construction...skipper
> skills....etc etc.....in my
> opinion focusing on perfection on one small part of the total equation
> that only
> makes the difference between good and bad over a small range of the total
> is
> wasted effort.....
(BS6566 Meranti) isn't all that much more expensive than domestic A/C fir
exterior, and is still less expensive than the epoxy required to seal the
whole boat. The cost savings just aren't that large, especially given the
extra difficulties of finishing fir as opposed to the tropical stuff.
-p
[Non-text portions of this message have been removed]
>...in my opinion focusing on perfection on one small partDitto. Also, wasted time & money.
> of the total equation that only makes the difference between
> good and bad over a small range of the total is wasted effort.....
>
> Blll
There are 100's of other real world things to worry about.
Why fixate on voids in plywood?
In a message dated 1/7/2008 9:53:07 AM Central Standard Time,
rocketgeek@...writes:
Since the highest stress on the panel is now much larger
for a given load on the panel, and the panel will start to fail as soon as
any part of it goes past the failure stress of the material, the entire
panel will fail at a much lower load than it would without the void
I disagree....
Unless your boat is designed to barely not break apart....this is more
theorectical than practical....
I used to work at a place where we "broke" stuff.....and we got pretty good
at making some high tech "fix"
look like magic...
We could take something.....and we knew pretty darn close at what "level"
something would "break"....
So, we would do a comparison test with normal item A....and super duper
"enhanced" item B......
So, with the test designed to "just barely" break A.....it would litterally
self destruct....however, say 10 percent "stronger" item B would be virtually
intact.....talk about DRAMATIC!
But what did that REALLY mean?
If your conditions are EXTREMELY well defined and predictable.....thats
GREAT....if your conditions range from easy to tear the shit outa
everything......not so much....
All this near perfect versus not nearly so perfect only buys you a SMALL
range out of a LARGE range of conditions under which the near perfect one saves
your butt.....
Given how varied sea conditions are.....boat
conditions...waves.....georgraphy....level of boat construction...skipper skills....etc etc.....in my
opinion focusing on perfection on one small part of the total equation that only
makes the difference between good and bad over a small range of the total is
wasted effort.....
Just my two cents
Blll
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
[Non-text portions of this message have been removed]
rocketgeek@...writes:
Since the highest stress on the panel is now much larger
for a given load on the panel, and the panel will start to fail as soon as
any part of it goes past the failure stress of the material, the entire
panel will fail at a much lower load than it would without the void
I disagree....
Unless your boat is designed to barely not break apart....this is more
theorectical than practical....
I used to work at a place where we "broke" stuff.....and we got pretty good
at making some high tech "fix"
look like magic...
We could take something.....and we knew pretty darn close at what "level"
something would "break"....
So, we would do a comparison test with normal item A....and super duper
"enhanced" item B......
So, with the test designed to "just barely" break A.....it would litterally
self destruct....however, say 10 percent "stronger" item B would be virtually
intact.....talk about DRAMATIC!
But what did that REALLY mean?
If your conditions are EXTREMELY well defined and predictable.....thats
GREAT....if your conditions range from easy to tear the shit outa
everything......not so much....
All this near perfect versus not nearly so perfect only buys you a SMALL
range out of a LARGE range of conditions under which the near perfect one saves
your butt.....
Given how varied sea conditions are.....boat
conditions...waves.....georgraphy....level of boat construction...skipper skills....etc etc.....in my
opinion focusing on perfection on one small part of the total equation that only
makes the difference between good and bad over a small range of the total is
wasted effort.....
Just my two cents
Blll
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
[Non-text portions of this message have been removed]
> any part of it goes past the failure stress of the material, the entireBut, we just don't hear of reports of boat hulls failing like this.
> panel will fail at a much lower load than it would without the void. Make
> sense?
>
> Pierce Nichols
I hear reports of rot. (Personally, I have only experienced rot, not
from voids, but rather from direct earth contact.) I am guessing that
rot is a regional phenomena. Also, I've heard some reports of wood
boaring ship worms.
I am not convinced that 'bending' is the main type of strength
important to boat hull skins. They achieve strength through 'shell
effect' which is not the same thing. You see stress concentration at
the edges of shells (at the taped seams), not in typically in the
middles.
Real world reports of catastrophic boat hull failures, due to voids or
whatever, are very scarce to nonexistant.
I am interesting in hearing first hand accounts of such.
Here is one first hand account of a catastrophic boat hull failure
from me: About a decade ago I was storing my Michalak Roar rowboat
under a rock cliff. After a rainstorm, a couple tons of rocks fell 50
feet and crushed the hull. Photos here:
http://hallman.org/bolger/roar/roar1.jpg
http://hallman.org/bolger/roar/roar.jpg
http://hallman.org/bolger/roar/cliff.jpg
http://hallman.org/bolger/roar/boulder.jpg
What I find to be interesting after studying that failure is that the
'shell effect' of that cheapo 1/4" laun plywood resisted the impact of
that rockfall with surprising resiliency. Also, looking past the
puncture holes, it was very revealing to notice the failure mode of
the taped seams. (Failure occurred due to wood fiber separation,
tensile.) And, FWIW, I easily patched her up in a weekend and she is
now slowly aging in my backyard, but still serviceable.
On Jan 7, 2008 5:43 AM, Stefan Probst <stefan.probst@opticom.v-nam.net>
wrote:
core (or in the skins, for that matter), it causes substantial stress risers
in both the core and the skins at that location. The stress risers are quite
a bit larger than you might think (much larger than simple redistribution of
the load the void should have been carrying), although how big is highly
details dependent. Since the highest stress on the panel is now much larger
for a given load on the panel, and the panel will start to fail as soon as
any part of it goes past the failure stress of the material, the entire
panel will fail at a much lower load than it would without the void. Make
sense?
Pierce Nichols
[Non-text portions of this message have been removed]
wrote:
> --- "Hajo Smulders" <hajosmulders@...> wrote:Well, either one would be dangerous. If there's a void of any kind in the
> > Voids will dramatically weaken this (I'm not talking a little bit;
> > when experimenting with fibverglals on foam years ago;
> > depending on the thickness of the foam the difference in buckling
> > strength would be 4 to 8 times! when i created intentional voids
> > in thicker foam to see if I could get away with cutting into
> > the foam to be able to make some compound curves)
> > You put a void in between two layers and snap....
>
> Can you elaborate a bit more and share your experiences?
> Maybe even a simple sketch?
>
> As I understand it, the purpose of the foam is mainly to keep the
> inner and outer skin at a fixed distance. In other words: bending
> forces result in forces that try to compress the foam perpendicular to
> the area of the skins. So a void would be dangerous, whereas a small
> gap at the side where the skin is stretched should not be that
> critical, no?
core (or in the skins, for that matter), it causes substantial stress risers
in both the core and the skins at that location. The stress risers are quite
a bit larger than you might think (much larger than simple redistribution of
the load the void should have been carrying), although how big is highly
details dependent. Since the highest stress on the panel is now much larger
for a given load on the panel, and the panel will start to fail as soon as
any part of it goes past the failure stress of the material, the entire
panel will fail at a much lower load than it would without the void. Make
sense?
Pierce Nichols
[Non-text portions of this message have been removed]
--- "Hajo Smulders" <hajosmulders@...> wrote:
Maybe even a simple sketch?
As I understand it, the purpose of the foam is mainly to keep the
inner and outer skin at a fixed distance. In other words: bending
forces result in forces that try to compress the foam perpendicular to
the area of the skins. So a void would be dangerous, whereas a small
gap at the side where the skin is stretched should not be that
critical, no?
Thanks,
Stefan
> Voids will dramatically weaken this (I'm not talking a little bit;Can you elaborate a bit more and share your experiences?
> when experimenting with fibverglals on foam years ago;
> depending on the thickness of the foam the difference in buckling
> strength would be 4 to 8 times! when i created intentional voids
> in thicker foam to see if I could get away with cutting into
> the foam to be able to make some compound curves)
> You put a void in between two layers and snap....
Maybe even a simple sketch?
As I understand it, the purpose of the foam is mainly to keep the
inner and outer skin at a fixed distance. In other words: bending
forces result in forces that try to compress the foam perpendicular to
the area of the skins. So a void would be dangerous, whereas a small
gap at the side where the skin is stretched should not be that
critical, no?
Thanks,
Stefan
> > Hasn't the main concern about voidsI don't know how large your voids are, and whether they are only in
> > been an issue of rot risk?
one layer. If you fasten your ply with screws or nails to chine logs,
stringers, etc., and you hit a void, then the head will sink in too
much, often even breaking/cracking/splintering the outer layer. No big
problem if you like sanding and will top all your screws anyway with
epoxy to make them invisible. But if you are aiming at a workman's
finish, then the voids are a pain.
At least this is how I see it/them.
Cheers,
Stefan
You don't need rot just swelling of the faces over the void for it to
swell up. Can you tell us if you glassed and encasulated painted or
what to the plywood.
Jon
swell up. Can you tell us if you glassed and encasulated painted or
what to the plywood.
Jon
--- Inbolger@yahoogroups.com, "Phillip Lea" <phillip_lea@...> wrote:
>
> --- Inbolger@yahoogroups.com, "Bruce Hallman" <bruce@> wrote:
> > I never understood the concern about 'voids' in plywood.
>
> I can attest to the void causing rot from the inside out. My 7-
year
> old June bug of 1/4" Superply showed some raised grain in a narrow
band
> along the inside bottom running athwartships. My fingernail easily
> broke through the ply showing off a previouly unknown void 20" by
1/4".
>
> Phil
>
--- Inbolger@yahoogroups.com, "Bruce Hallman" <bruce@...> wrote:
old June bug of 1/4" Superply showed some raised grain in a narrow band
along the inside bottom running athwartships. My fingernail easily
broke through the ply showing off a previouly unknown void 20" by 1/4".
Phil
> I never understood the concern about 'voids' in plywood.I can attest to the void causing rot from the inside out. My 7-year
old June bug of 1/4" Superply showed some raised grain in a narrow band
along the inside bottom running athwartships. My fingernail easily
broke through the ply showing off a previouly unknown void 20" by 1/4".
Phil
To me the strength issue is not so important in composite sandwich
Lets take a simple example.....say a inch wide strip of plywood several feet
long.........
Now lets bend it into a bow shape until it breaks.....
Now, lets say in the center (length wise) of the strip we have a major void
a good fraction of that one inch width....
Now, its pretty obvious that the bent strip will break under MUCH less
stress than the same strip without the void...
Now, if both surfaces have significant glass and epoxy, that difference
between void and void free strength will probably be significant....but not
nearly as dramatic....but again still significant....
Now, lets make that strip feet wide as well as feet long.....you know like
your HULL.....now the void aint gonna make a measurable difference...unless the
void is BIGGGGG...
So, as far as hull strength goes....voids are mostly an imaginary issue in
my opinion....
Now, as a point where leakage or rot may occur....thats more of an
issue...but if your boat design isnt designed to deal with a small leak or
"swampage"...thats just not safe void or no voids in my totally amatuer opinion....
Now, you obviously cant have major voids in CRITICAL areas...but thats what
solid wood...or multiple layers of ply are for.....
just my two cents
Blll
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
[Non-text portions of this message have been removed]
> construction, it is more of a concern in boats without epoxy/glassOn the issue of voids....
> sheathing.
Lets take a simple example.....say a inch wide strip of plywood several feet
long.........
Now lets bend it into a bow shape until it breaks.....
Now, lets say in the center (length wise) of the strip we have a major void
a good fraction of that one inch width....
Now, its pretty obvious that the bent strip will break under MUCH less
stress than the same strip without the void...
Now, if both surfaces have significant glass and epoxy, that difference
between void and void free strength will probably be significant....but not
nearly as dramatic....but again still significant....
Now, lets make that strip feet wide as well as feet long.....you know like
your HULL.....now the void aint gonna make a measurable difference...unless the
void is BIGGGGG...
So, as far as hull strength goes....voids are mostly an imaginary issue in
my opinion....
Now, as a point where leakage or rot may occur....thats more of an
issue...but if your boat design isnt designed to deal with a small leak or
"swampage"...thats just not safe void or no voids in my totally amatuer opinion....
Now, you obviously cant have major voids in CRITICAL areas...but thats what
solid wood...or multiple layers of ply are for.....
just my two cents
Blll
**************Start the year off right. Easy ways to stay in shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
[Non-text portions of this message have been removed]
> Glassing on the outside adds durability but little strength unless thick and heavy.Strength. There are different types. Bending, compression, shear,
torsional and tensile.
The strength issue with boat hulls is complex and a mix of all these,
but the largest component of strength in hulls is the shell effect
which comes mostly from tensile (and compressive) strength.
Fiberglass has awesome tensile strength properties and good
compressive strength too.
Pull a single fiber strand out of fiberglass cloth and try to break it
with your bare hands to see.
Fiberglass adds much more than just durability, it adds tremendously
to the tensile strength of plywood.
I agree that large ply voids degrade shear, bending and torsional
strength, but I don't see that those are the most important types of
strength with fiberglassed plywood boats.
> To me the strength issue is not so important in composite sandwichKen -
> construction, it is more of a concern in boats without epoxy/glass
> sheathing.
I agree with you here. I built a Nymph over 24 years ago that is still
going strong and on it's 3rd owner. I used 1/4" AC ply, but it was
completed sheathed and sealed with cloth set in polyester resin.
I was going to start on a June Bug today after finding a local lumber
yard with stacks of 1/4" ACx, but realized I wanted to go with Okoume
as it is 5 ply and much lighter/stronger than the 3 ply fir AC. Will
need to drive to Somerville of Providence to pick up a load of it.
David Jost
When you see a ply with a small void that gets wet then both sides of
the ply swell along the void the why not is answered. Glasasing on the
outside adds durability but little stringth unless thick and heavy.
Epoxy coating on the inside helps keep water out. The solution is to
fill the void with thickened epoxy if you can find it. poking a small
wire down it can tell you if it goes through. 1/8" drill hole into the
void at intervals and a seyrnge with thickened epoxy will do the trick.
Stand sheet on edge tape over void at bottom edge. Start a bottom hole
injecting epoxy till it fills to the next hole remove syrnge and tape
over hole. Move to the next hole up till you get to the top. This way
there is no air traped and the void in the inerply is filled gluing the
outerplys.
Jon
--- Inbolger@yahoogroups.com, Kenneth Grome <bagacayboatworks@...>
wrote:
the ply swell along the void the why not is answered. Glasasing on the
outside adds durability but little stringth unless thick and heavy.
Epoxy coating on the inside helps keep water out. The solution is to
fill the void with thickened epoxy if you can find it. poking a small
wire down it can tell you if it goes through. 1/8" drill hole into the
void at intervals and a seyrnge with thickened epoxy will do the trick.
Stand sheet on edge tape over void at bottom edge. Start a bottom hole
injecting epoxy till it fills to the next hole remove syrnge and tape
over hole. Move to the next hole up till you get to the top. This way
there is no air traped and the void in the inerply is filled gluing the
outerplys.
Jon
--- Inbolger@yahoogroups.com, Kenneth Grome <bagacayboatworks@...>
wrote:
>simply
> > Hasn't the main concern about voids
> > been an issue of rot risk?
>
> I thought it was for a long time, but then I realized that it may
> be a concern about structural strength.
>
> To me the strength issue is not so important in composite sandwich
> construction, it is more of a concern in boats without epoxy/glass
> sheathing.
>
> Sincerely,
> Ken Grome
> Bagacay Boatworks
> www.bagacayboatworks.com
>
> Hasn't the main concern about voidsI thought it was for a long time, but then I realized that it may simply
> been an issue of rot risk?
be a concern about structural strength.
To me the strength issue is not so important in composite sandwich
construction, it is more of a concern in boats without epoxy/glass
sheathing.
Sincerely,
Ken Grome
Bagacay Boatworks
www.bagacayboatworks.com
Thanks John,
I probably will, but if Bob Hicks does like he did on the Florida
piece it won't appear until this time next year:) I had a great
cruise this summer in Voyageur's National Park. It is a fantastic
cruising ground for those of you who don't know this. When I get to
Texas maybe I will write that up for Bob to put in for a summer issue.
Bob Slimak
--- Inbolger@yahoogroups.com, John Bell <smallboatdesigner@...>
wrote:
I probably will, but if Bob Hicks does like he did on the Florida
piece it won't appear until this time next year:) I had a great
cruise this summer in Voyageur's National Park. It is a fantastic
cruising ground for those of you who don't know this. When I get to
Texas maybe I will write that up for Bob to put in for a summer issue.
Bob Slimak
--- Inbolger@yahoogroups.com, John Bell <smallboatdesigner@...>
wrote:
>TX
> ...I'm really enjoying your series about cruising in FL in the last
> couple of MAIBs. Here's hoping you'll have something to write about
> later on.Their
>
> Bob Slimak wrote:
> > You might try noahsmarine.com for good prices on marine ply.
> > BS1088 Okume is about $59.00 for 6mm 5 ply. I built my Bantamusing
> > their Meranti BS6566 (may have the number not quite right)and itwas
> > excellant stuff. the 6mm 5 ply is $29.00 a sheet, $26 somethingfor
> > 10 or more. It is so pretty that it seems a shame to paint it,until
> > I remember what a pain in the #*% brightword is. I prefer layingin
> > the hammock while reading and drinking a stout to scraping,sanding
> > and varnishing:) Unless you live near Toronto, or Niagra Falls,NY,
> > it doesn't pay to have two or three sheets truck shipped. If youneed
> > 10 or more it does.YEA!
> >
> > Bob Slimak
> >
> > leaving the cold shores of Duluth for Padre Island, TX tomorrow.
> >because I
> >
> >
> >
> >
> > --- Inbolger@yahoogroups.com, Clyde Wisner <clydewis@> wrote:
> >
> >> 1/4 inch ought to have 5 plys. I built my Lily with 3 ply
> >> didn't want to take the time to return it and it was okay, butvery
> >> difficult to bend. Clyde40yahoogroups.com>,
> >>
> >> Peter Lenihan wrote:
> >>
> >>
> >>> --- Inbolger@yahoogroups.com<mailto:bolger%
> >>>would
> > Clyde
> >
> >>> Wisner <clydewis@> wrote:
> >>>
> >>>> Pricing I've gotten for "signal MDO" is higher than Okoume ply.
> >>>>
> >>> The Okoume ply I've seen(3/8") looked like nothing more then two
> >>> lovely, but very thin, outside veneers sandwiching something not
> >>> unlike soda biscuit.Easy to snap a piece over my knee and I
> >>>it
> > not
> >
> >>> want to be the guy who has to sand those surfaces too much as
> >>>Okoume
> > would
> >
> >>> not take a lot to punch through into that odd, brittle, interior
> >>> laminate.
> >>>
> >>> But then again, what I saw may have been some really"cheap"
> >>> passing itself off as topshelf "marine" plywood.flogging dead horses
> >>>
> >>> Peter Lenihan
> >>>
> >>>
> >>>
> >>
> >>
> >> [Non-text portions of this message have been removed]
> >>
> >>
> >
> >
> >
> >
> > Bolger rules!!!
> > - NO "GO AWAY SPAMMER!" posts!!! Please!
> > - no cursing, flaming, trolling, spamming, respamming, or
> > - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred'posts
> > - Pls add your comments at the TOP, SIGN your posts, and snip away01930, Fax: (978) 282-1349
> > - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
> > - Unsubscribe:bolger-unsubscribe@yahoogroups.comsubscribe@yahoogroups.com
> > - Open discussion: bolger_coffee_lounge-
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
>
On Jan 4, 2008 8:36 AM, Hajo Smulders <hajosmulders@...> wrote:
with the bulk of the strength coming from skin tension. Epoxied
fiberglass sheathing is an excellent source for skin tension, with
fiberglass having excellent tension strength qualities. The "break it
across your knee" test is not a direct way to evaluate shell strength.
Hasn't the main concern about voids been an issue of rot risk?
> If you don't understand the concern about voids try to break one on yourI know what you are saying, but boat hulls are more like 'shells',
> knee and you'll find out.
with the bulk of the strength coming from skin tension. Epoxied
fiberglass sheathing is an excellent source for skin tension, with
fiberglass having excellent tension strength qualities. The "break it
across your knee" test is not a direct way to evaluate shell strength.
Hasn't the main concern about voids been an issue of rot risk?
There is a lot more nothing of anything than there is stuff.
(look at the standard model).
If you don't understand the concern about voids try to break one on your
knee and you'll find out.
Plywood layered relies on its shear and compression qualities for its
strength. Voids will dramatically weaken this (I'm not talking a little bit;
when experimenting with fibverglals on foam years ago; depending on the
thickness of the foam the difference in buckling strength would be 4 to 8
times! when i created intentional voids in thicker foam to see if I could
get away with cutting into the foam to be able to make some compaound
curves)
You put a void in between two layers and snap....
This is one of the great dangers of composite construction: If you have a
small leak in anouter layer of glass and the inner layer of wood (in a strip
glued boat or fiberglass on ply) or foam (Some foams are affected by
moisture) gets affected it will buckle unexpectedly.
Not a good thing when in the southern ocean...
Hajo
(look at the standard model).
If you don't understand the concern about voids try to break one on your
knee and you'll find out.
Plywood layered relies on its shear and compression qualities for its
strength. Voids will dramatically weaken this (I'm not talking a little bit;
when experimenting with fibverglals on foam years ago; depending on the
thickness of the foam the difference in buckling strength would be 4 to 8
times! when i created intentional voids in thicker foam to see if I could
get away with cutting into the foam to be able to make some compaound
curves)
You put a void in between two layers and snap....
This is one of the great dangers of composite construction: If you have a
small leak in anouter layer of glass and the inner layer of wood (in a strip
glued boat or fiberglass on ply) or foam (Some foams are affected by
moisture) gets affected it will buckle unexpectedly.
Not a good thing when in the southern ocean...
Hajo
On Jan 4, 2008 11:10 AM, Bruce Hallman <bruce@...> wrote:
> > certify that inner plies had no acceptable voids .....
>
> I never understood the concern about 'voids' in plywood.
> Have you ever looked at wood under a microscope?
> Wood is 90% void anyway.
>
>http://www.sbs.utexas.edu/mauseth/weblab/webchap15wood/web15.3-2.jpg
>
>
--
--------------------------------------------------------------------------------------------------
Q: How many women does it take to screw in a light bulb?
A: That's "womyn" with a Y, and it's not funny!
[Non-text portions of this message have been removed]
> certify that inner plies had no acceptable voids .....I never understood the concern about 'voids' in plywood.
Have you ever looked at wood under a microscope?
Wood is 90% void anyway.
http://www.sbs.utexas.edu/mauseth/weblab/webchap15wood/web15.3-2.jpg
The APA (American Plywood Association) stopped certifying
domestic "marine" plywood in the early 90s due to inability to
certify that inner plies had no acceptable voids .....
didn't see anything about re-instituting the grade
So it's imported (non-US) or exterior grade (glue used on inner
plies) at Gougeon they always recommended a "boil test". Cut a small
corner at pop it in a pan of boiling water for an hour or so. If it
doesn't delaminate then you should be in good shape.
I always got mine at Detroit Lumber excellent prices for 3/8" AC
Exterior
--- Inbolger@yahoogroups.com, "Peter Lenihan" <peterlenihan@...>
wrote:
domestic "marine" plywood in the early 90s due to inability to
certify that inner plies had no acceptable voids .....
didn't see anything about re-instituting the grade
So it's imported (non-US) or exterior grade (glue used on inner
plies) at Gougeon they always recommended a "boil test". Cut a small
corner at pop it in a pan of boiling water for an hour or so. If it
doesn't delaminate then you should be in good shape.
I always got mine at Detroit Lumber excellent prices for 3/8" AC
Exterior
--- Inbolger@yahoogroups.com, "Peter Lenihan" <peterlenihan@...>
wrote:
>sh.,
> --- Inbolger@yahoogroups.com, "Gene Lueg" <genenkay@> wrote:
> >
> > The Okoume to which you refer is not marine ply, it is cabinet
> grade ply. My
> > friend/salesman at Hogan Hardwoods let me in on this and refused
> to sell it
> > to me for a boat. Incidentally i could have gotten it for $14
> noanyway
> > shipping.
> >
> > Gene Lueg
>
> Thanks Gene and Kenneth for shedding some good light upon this. It
> just goes to show that there are indeed some ignorant,negligent or
> dishonest vendors out there willing to make a quick good buck
> they can. Buyer beware!!
>
> Sincerely,
>
> Peter Lenihan, hooked on MDO and loving every minute of it!
>
--- Inbolger@yahoogroups.com, "Gene Lueg" <genenkay@...> wrote:
just goes to show that there are indeed some ignorant,negligent or
dishonest vendors out there willing to make a quick good buck anyway
they can. Buyer beware!!
Sincerely,
Peter Lenihan, hooked on MDO and loving every minute of it!
>grade ply. My
> The Okoume to which you refer is not marine ply, it is cabinet
> friend/salesman at Hogan Hardwoods let me in on this and refusedto sell it
> to me for a boat. Incidentally i could have gotten it for $14 sh.,no
> shipping.Thanks Gene and Kenneth for shedding some good light upon this. It
>
> Gene Lueg
just goes to show that there are indeed some ignorant,negligent or
dishonest vendors out there willing to make a quick good buck anyway
they can. Buyer beware!!
Sincerely,
Peter Lenihan, hooked on MDO and loving every minute of it!
...I'm really enjoying your series about cruising in FL in the last
couple of MAIBs. Here's hoping you'll have something to write about TX
later on.
Bob Slimak wrote:
couple of MAIBs. Here's hoping you'll have something to write about TX
later on.
Bob Slimak wrote:
> You might try noahsmarine.com for good prices on marine ply. Their
> BS1088 Okume is about $59.00 for 6mm 5 ply. I built my Bantam using
> their Meranti BS6566 (may have the number not quite right)and it was
> excellant stuff. the 6mm 5 ply is $29.00 a sheet, $26 something for
> 10 or more. It is so pretty that it seems a shame to paint it, until
> I remember what a pain in the #*% brightword is. I prefer laying in
> the hammock while reading and drinking a stout to scraping, sanding
> and varnishing:) Unless you live near Toronto, or Niagra Falls, NY,
> it doesn't pay to have two or three sheets truck shipped. If you need
> 10 or more it does.
>
> Bob Slimak
>
> leaving the cold shores of Duluth for Padre Island, TX tomorrow. YEA!
>
>
>
>
>
> --- Inbolger@yahoogroups.com, Clyde Wisner <clydewis@...> wrote:
>
>> 1/4 inch ought to have 5 plys. I built my Lily with 3 ply because I
>> didn't want to take the time to return it and it was okay, but very
>> difficult to bend. Clyde
>>
>> Peter Lenihan wrote:
>>
>>
>>> --- Inbolger@yahoogroups.com<mailto:bolger%40yahoogroups.com>,
>>>
> Clyde
>
>>> Wisner <clydewis@> wrote:
>>>
>>>> Pricing I've gotten for "signal MDO" is higher than Okoume ply.
>>>>
>>> The Okoume ply I've seen(3/8") looked like nothing more then two
>>> lovely, but very thin, outside veneers sandwiching something not
>>> unlike soda biscuit.Easy to snap a piece over my knee and I would
>>>
> not
>
>>> want to be the guy who has to sand those surfaces too much as it
>>>
> would
>
>>> not take a lot to punch through into that odd, brittle, interior
>>> laminate.
>>>
>>> But then again, what I saw may have been some really"cheap" Okoume
>>> passing itself off as topshelf "marine" plywood.
>>>
>>> Peter Lenihan
>>>
>>>
>>>
>>
>>
>> [Non-text portions of this message have been removed]
>>
>>
>
>
>
>
> Bolger rules!!!
> - NO "GO AWAY SPAMMER!" posts!!! Please!
> - no cursing, flaming, trolling, spamming, respamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - Pls add your comments at the TOP, SIGN your posts, and snip away
> - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax: (978) 282-1349
> - Unsubscribe:bolger-unsubscribe@yahoogroups.com
> - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
> Yahoo! Groups Links
>
>
>
>
>
I followed the link to Anderson in Anaheim, CA and thought the marine
plywood they were selling didn't sound unreasonably priced. Does anyone
know of a comparable source of supply for plywood located close to Savannah,
GA? The thought of freighting charges on a boatload of plywood from the
Left Coast gives me the tizzies.
By the way, how does the cheaper Meranti compare to the Okumi marine
plywood? Are there significant differences in workability, use in boats?
My limited experience in building small boats supports Tim Anderson's
comments. I built one Bolger canoe years ago in Germany using HL market
plywood (?). At least I thought it was plywood. It lasted all of one
summers use on the Main and Lahn rivers, the best part of three weeks in
July before it delam'ed on me. For the time invested I should have bought
a German dictionary when I went shopping for the plywood, etc., instead of
using my street Italian on the Turkish guys who helped me find the wood.
Spater, SSK
[Non-text portions of this message have been removed]
plywood they were selling didn't sound unreasonably priced. Does anyone
know of a comparable source of supply for plywood located close to Savannah,
GA? The thought of freighting charges on a boatload of plywood from the
Left Coast gives me the tizzies.
By the way, how does the cheaper Meranti compare to the Okumi marine
plywood? Are there significant differences in workability, use in boats?
My limited experience in building small boats supports Tim Anderson's
comments. I built one Bolger canoe years ago in Germany using HL market
plywood (?). At least I thought it was plywood. It lasted all of one
summers use on the Main and Lahn rivers, the best part of three weeks in
July before it delam'ed on me. For the time invested I should have bought
a German dictionary when I went shopping for the plywood, etc., instead of
using my street Italian on the Turkish guys who helped me find the wood.
Spater, SSK
[Non-text portions of this message have been removed]
You might try noahsmarine.com for good prices on marine ply. Their
BS1088 Okume is about $59.00 for 6mm 5 ply. I built my Bantam using
their Meranti BS6566 (may have the number not quite right)and it was
excellant stuff. the 6mm 5 ply is $29.00 a sheet, $26 something for
10 or more. It is so pretty that it seems a shame to paint it, until
I remember what a pain in the #*% brightword is. I prefer laying in
the hammock while reading and drinking a stout to scraping, sanding
and varnishing:) Unless you live near Toronto, or Niagra Falls, NY,
it doesn't pay to have two or three sheets truck shipped. If you need
10 or more it does.
Bob Slimak
leaving the cold shores of Duluth for Padre Island, TX tomorrow. YEA!
BS1088 Okume is about $59.00 for 6mm 5 ply. I built my Bantam using
their Meranti BS6566 (may have the number not quite right)and it was
excellant stuff. the 6mm 5 ply is $29.00 a sheet, $26 something for
10 or more. It is so pretty that it seems a shame to paint it, until
I remember what a pain in the #*% brightword is. I prefer laying in
the hammock while reading and drinking a stout to scraping, sanding
and varnishing:) Unless you live near Toronto, or Niagra Falls, NY,
it doesn't pay to have two or three sheets truck shipped. If you need
10 or more it does.
Bob Slimak
leaving the cold shores of Duluth for Padre Island, TX tomorrow. YEA!
--- Inbolger@yahoogroups.com, Clyde Wisner <clydewis@...> wrote:
>
> 1/4 inch ought to have 5 plys. I built my Lily with 3 ply because I
> didn't want to take the time to return it and it was okay, but very
> difficult to bend. Clyde
>
> Peter Lenihan wrote:
>
> > --- Inbolger@yahoogroups.com<mailto:bolger%40yahoogroups.com>,
Clyde
> > Wisner <clydewis@> wrote:
> > >
> > > Pricing I've gotten for "signal MDO" is higher than Okoume ply.
> >
> > The Okoume ply I've seen(3/8") looked like nothing more then two
> > lovely, but very thin, outside veneers sandwiching something not
> > unlike soda biscuit.Easy to snap a piece over my knee and I would
not
> > want to be the guy who has to sand those surfaces too much as it
would
> > not take a lot to punch through into that odd, brittle, interior
> > laminate.
> >
> > But then again, what I saw may have been some really"cheap" Okoume
> > passing itself off as topshelf "marine" plywood.
> >
> > Peter Lenihan
> >
> >
>
>
>
>
> [Non-text portions of this message have been removed]
>
The Okoume to which you refer is not marine ply, it is cabinet grade ply. My
friend/salesman at Hogan Hardwoods let me in on this and refused to sell it
to me for a boat. Incidentally i could have gotten it for $14 sh., no
shipping.
Gene Lueg
friend/salesman at Hogan Hardwoods let me in on this and refused to sell it
to me for a boat. Incidentally i could have gotten it for $14 sh., no
shipping.
Gene Lueg
On Jan 2, 2008 7:28 PM, Kenneth Grome <bagacayboatworks@...> wrote:
> > The Okoume ply I've seen(3/8") looked like nothing more then two
> > lovely, but very thin, outside veneers sandwiching something not
> > unlike soda biscuit.Easy to snap a piece over my knee and I would
> > not want to be the guy who has to sand those surfaces too much as it
> > would not take a lot to punch through into that odd, brittle,
> > interior laminate.
>
>
> This sounds like the cheap Okoume plywood I mentioned here (or in
> another boating group) the other day which is being made in volume in
> China, then imported at low prices to the USA. It is made with two
> paper-thin face plies of Okoume, and the core ply is cheap Poplar --
> which is neither a strong nor a durable boat building material.
>
> Sincerely,
> Ken Grome
> Bagacay Boatworks
> www.bagacayboatworks.com
>
>
>
>
>
>
>
>
> Bolger rules!!!
> - NO "GO AWAY SPAMMER!" posts!!! Please!
> - no cursing, flaming, trolling, spamming, respamming, or flogging dead
> horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - Pls add your comments at the TOP, SIGN your posts, and snip away
> - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
> (978) 282-1349
> - Unsubscribe:bolger-unsubscribe@yahoogroups.com
> - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
> Yahoo! Groups Links
>
>
>
>
[Non-text portions of this message have been removed]
> The Okoume ply I've seen(3/8") looked like nothing more then twoThis sounds like the cheap Okoume plywood I mentioned here (or in
> lovely, but very thin, outside veneers sandwiching something not
> unlike soda biscuit.Easy to snap a piece over my knee and I would
> not want to be the guy who has to sand those surfaces too much as it
> would not take a lot to punch through into that odd, brittle,
> interior laminate.
another boating group) the other day which is being made in volume in
China, then imported at low prices to the USA. It is made with two
paper-thin face plies of Okoume, and the core ply is cheap Poplar --
which is neither a strong nor a durable boat building material.
Sincerely,
Ken Grome
Bagacay Boatworks
www.bagacayboatworks.com
I prefer Joubert Okoume Marine from Anderson International Trading
www.aitwood.com <http://www.aitwood.com/> has 5 ply 6 m/m for $52.98 per
sheet; Beautiful stuff and worth the price, it has a BS1088 rating. I have
built a mess of plywood and cold-molded boats and one plywood airplane and
this is the best that I've seen. I just bought all of the plywood to build
Bolger's Marine Van $5400.00 (I'm stretching it to 29'), but I'll save many
hours of finishing time. The greatest investment that we make is our time,
and it is not replaceable; I used to build out of any thing I could find
until I realized that if it was worth the investment in time then it was
worth the money for the best materials that i could find. Tim P Anderson
_____
From:bolger@yahoogroups.com[mailto:bolger@yahoogroups.com] On Behalf Of
Clyde Wisner
Sent: Wednesday, January 02, 2008 7:54 AM
To:bolger@yahoogroups.com
Subject: Re: [bolger] Re: Plywood Again???
Pricing I've gotten for "signal MDO" is higher than Okoume ply. I'm sure
it's very good but regular MDO is where the savings is. There may be
voids to fill and it is heavy but I've had some outside for a year and
nothing is apparent. I sided my boat shed 3/8,10ft sheets but didn't get
around to painting, and it makes a not unattractive building with green
ondura roof. Clyde PS I think I mentioned earlier, that 8ft long, 10 ft
high wall sections are all I and a friend wanted to lift to stand up.
Peter Lenihan wrote:
[Non-text portions of this message have been removed]
www.aitwood.com <http://www.aitwood.com/> has 5 ply 6 m/m for $52.98 per
sheet; Beautiful stuff and worth the price, it has a BS1088 rating. I have
built a mess of plywood and cold-molded boats and one plywood airplane and
this is the best that I've seen. I just bought all of the plywood to build
Bolger's Marine Van $5400.00 (I'm stretching it to 29'), but I'll save many
hours of finishing time. The greatest investment that we make is our time,
and it is not replaceable; I used to build out of any thing I could find
until I realized that if it was worth the investment in time then it was
worth the money for the best materials that i could find. Tim P Anderson
_____
From:bolger@yahoogroups.com[mailto:bolger@yahoogroups.com] On Behalf Of
Clyde Wisner
Sent: Wednesday, January 02, 2008 7:54 AM
To:bolger@yahoogroups.com
Subject: Re: [bolger] Re: Plywood Again???
Pricing I've gotten for "signal MDO" is higher than Okoume ply. I'm sure
it's very good but regular MDO is where the savings is. There may be
voids to fill and it is heavy but I've had some outside for a year and
nothing is apparent. I sided my boat shed 3/8,10ft sheets but didn't get
around to painting, and it makes a not unattractive building with green
ondura roof. Clyde PS I think I mentioned earlier, that 8ft long, 10 ft
high wall sections are all I and a friend wanted to lift to stand up.
Peter Lenihan wrote:
> --- In bolger@yahoogroups. <mailto:bolger%40yahoogroups.com> com<mailto:bolger%40yahoogroups.com>,
> "mike" <mikearedmond@...> wrote:[Non-text portions of this message have been removed]
> >
> > Hi everybody an a happy New Year thrown in there also,,,Must be the
> > Scrooge in me, taking over my boat building urges...been chequing
> some
> > posts on the internet concerning Ultraply,,some kind of supposed to
> be
> > good quality underlay plywood.(Still have to find out if it is
> > available in Canada ei specifically Edmonton area).Has anyone built
> a
> > boat with this stuff amonsght all of you fellows,ei;also awfull
> curious
> > about MDO...Mike
>
> Hi Mike,
>
> Cannot speak to your Ultraply query but can probably go on for ages
> about MDO :-)
> I have used it in the past for a MICRO I built(see files section in
> the MICRO folder; Lenihan's MICRO) and continued using it during the
> build of my Bolger WINDERMERE esturary cruiser.The best stuff I have
> found is from Olympic ply,ex-Simpsonply, called SIGNAL MDO. Absolutely
> great stuff,virtually no voids,waterproof glue between the laminates
> and takes a finish like magic and much cheaper then marine ply. I am
> sure if you drill around this group, via the search function, you'll
> come up with lots of recommendations/discussions about the virtues of
> MDO. Just be certain you are getting top quality MDO and stuff that
> looks like it was wrapped in Kraft paper :-)
> What are you looking to build with MDO?
>
> Sincerely,
>
> Peter Lenihan, a not too unbiased person regarding MDO, from along the
> snow covered,swept and frozen shores of the St.Lawrence...........
>
> >
>
>
[Non-text portions of this message have been removed]
1/4 inch ought to have 5 plys. I built my Lily with 3 ply because I
didn't want to take the time to return it and it was okay, but very
difficult to bend. Clyde
Peter Lenihan wrote:
didn't want to take the time to return it and it was okay, but very
difficult to bend. Clyde
Peter Lenihan wrote:
> --- Inbolger@yahoogroups.com<mailto:bolger%40yahoogroups.com>, Clyde[Non-text portions of this message have been removed]
> Wisner <clydewis@...> wrote:
> >
> > Pricing I've gotten for "signal MDO" is higher than Okoume ply.
>
> The Okoume ply I've seen(3/8") looked like nothing more then two
> lovely, but very thin, outside veneers sandwiching something not
> unlike soda biscuit.Easy to snap a piece over my knee and I would not
> want to be the guy who has to sand those surfaces too much as it would
> not take a lot to punch through into that odd, brittle, interior
> laminate.
>
> But then again, what I saw may have been some really"cheap" Okoume
> passing itself off as topshelf "marine" plywood.
>
> Peter Lenihan
>
>
--- Inbolger@yahoogroups.com, Clyde Wisner <clydewis@...> wrote:
lovely, but very thin, outside veneers sandwiching something not
unlike soda biscuit.Easy to snap a piece over my knee and I would not
want to be the guy who has to sand those surfaces too much as it would
not take a lot to punch through into that odd, brittle, interior
laminate.
But then again, what I saw may have been some really"cheap" Okoume
passing itself off as topshelf "marine" plywood.
Peter Lenihan
>The Okoume ply I've seen(3/8") looked like nothing more then two
> Pricing I've gotten for "signal MDO" is higher than Okoume ply.
lovely, but very thin, outside veneers sandwiching something not
unlike soda biscuit.Easy to snap a piece over my knee and I would not
want to be the guy who has to sand those surfaces too much as it would
not take a lot to punch through into that odd, brittle, interior
laminate.
But then again, what I saw may have been some really"cheap" Okoume
passing itself off as topshelf "marine" plywood.
Peter Lenihan
Pricing I've gotten for "signal MDO" is higher than Okoume ply. I'm sure
it's very good but regular MDO is where the savings is. There may be
voids to fill and it is heavy but I've had some outside for a year and
nothing is apparent. I sided my boat shed 3/8,10ft sheets but didn't get
around to painting, and it makes a not unattractive building with green
ondura roof. Clyde PS I think I mentioned earlier, that 8ft long, 10 ft
high wall sections are all I and a friend wanted to lift to stand up.
Peter Lenihan wrote:
it's very good but regular MDO is where the savings is. There may be
voids to fill and it is heavy but I've had some outside for a year and
nothing is apparent. I sided my boat shed 3/8,10ft sheets but didn't get
around to painting, and it makes a not unattractive building with green
ondura roof. Clyde PS I think I mentioned earlier, that 8ft long, 10 ft
high wall sections are all I and a friend wanted to lift to stand up.
Peter Lenihan wrote:
> --- Inbolger@yahoogroups.com<mailto:bolger%40yahoogroups.com>,[Non-text portions of this message have been removed]
> "mike" <mikearedmond@...> wrote:
> >
> > Hi everybody an a happy New Year thrown in there also,,,Must be the
> > Scrooge in me, taking over my boat building urges...been chequing
> some
> > posts on the internet concerning Ultraply,,some kind of supposed to
> be
> > good quality underlay plywood.(Still have to find out if it is
> > available in Canada ei specifically Edmonton area).Has anyone built
> a
> > boat with this stuff amonsght all of you fellows,ei;also awfull
> curious
> > about MDO...Mike
>
> Hi Mike,
>
> Cannot speak to your Ultraply query but can probably go on for ages
> about MDO :-)
> I have used it in the past for a MICRO I built(see files section in
> the MICRO folder; Lenihan's MICRO) and continued using it during the
> build of my Bolger WINDERMERE esturary cruiser.The best stuff I have
> found is from Olympic ply,ex-Simpsonply, called SIGNAL MDO. Absolutely
> great stuff,virtually no voids,waterproof glue between the laminates
> and takes a finish like magic and much cheaper then marine ply. I am
> sure if you drill around this group, via the search function, you'll
> come up with lots of recommendations/discussions about the virtues of
> MDO. Just be certain you are getting top quality MDO and stuff that
> looks like it was wrapped in Kraft paper :-)
> What are you looking to build with MDO?
>
> Sincerely,
>
> Peter Lenihan, a not too unbiased person regarding MDO, from along the
> snow covered,swept and frozen shores of the St.Lawrence...........
>
> >
>
>
Hi Mike -
IF you search "UltraPly," you'll find a couple of threads in the various yahoogroups.
A couple of folks on the Michalak Yahoo group (they're probably on this group, too) have built with UltraPly and have reported good results/longevity.
I'm currently building Michalak's AF3 with the stuff. It's very pleasant to work with -- cuts nice, no voids, almost no sanding required for finishing. It passed the "throw some pieces in the dishwasher for a week and see what happens" test. Some people have expressed concerns about the video at the product's web site where a flooring installer scores a sheet with a utility knife and snaps the piece right along the score line. The guy in the video must be mighty strong, because I have been unable to replicate this. After repeated scoring with as much pressure as I could muster, I was able to bend the sheet through 2 plies, but the bottom ply splintered. I got essentially the same results with a regular lumberyard sheet of 1/4 inch ply.
You can check out my AF3 project athttp://webpages.charter.net/cassidy1
David C
---- mike <mikearedmond@...> wrote:
IF you search "UltraPly," you'll find a couple of threads in the various yahoogroups.
A couple of folks on the Michalak Yahoo group (they're probably on this group, too) have built with UltraPly and have reported good results/longevity.
I'm currently building Michalak's AF3 with the stuff. It's very pleasant to work with -- cuts nice, no voids, almost no sanding required for finishing. It passed the "throw some pieces in the dishwasher for a week and see what happens" test. Some people have expressed concerns about the video at the product's web site where a flooring installer scores a sheet with a utility knife and snaps the piece right along the score line. The guy in the video must be mighty strong, because I have been unable to replicate this. After repeated scoring with as much pressure as I could muster, I was able to bend the sheet through 2 plies, but the bottom ply splintered. I got essentially the same results with a regular lumberyard sheet of 1/4 inch ply.
You can check out my AF3 project athttp://webpages.charter.net/cassidy1
David C
---- mike <mikearedmond@...> wrote:
> Hi everybody an a happy New Year thrown in there also,,,Must be the
> Scrooge in me, taking over my boat building urges...been chequing some
> posts on the internet concerning Ultraply,,some kind of supposed to be
> good quality underlay plywood.(Still have to find out if it is
> available in Canada ei specifically Edmonton area).Has anyone built a
> boat with this stuff amonsght all of you fellows,ei;also awfull curious
> about MDO...Mike
>
>
--- Inbolger@yahoogroups.com, "mike" <mikearedmond@...> wrote:
Cannot speak to your Ultraply query but can probably go on for ages
about MDO :-)
I have used it in the past for a MICRO I built(see files section in
the MICRO folder; Lenihan's MICRO) and continued using it during the
build of my Bolger WINDERMERE esturary cruiser.The best stuff I have
found is from Olympic ply,ex-Simpsonply, called SIGNAL MDO. Absolutely
great stuff,virtually no voids,waterproof glue between the laminates
and takes a finish like magic and much cheaper then marine ply. I am
sure if you drill around this group, via the search function, you'll
come up with lots of recommendations/discussions about the virtues of
MDO. Just be certain you are getting top quality MDO and stuff that
looks like it was wrapped in Kraft paper :-)
What are you looking to build with MDO?
Sincerely,
Peter Lenihan, a not too unbiased person regarding MDO, from along the
snow covered,swept and frozen shores of the St.Lawrence...........
>some
> Hi everybody an a happy New Year thrown in there also,,,Must be the
> Scrooge in me, taking over my boat building urges...been chequing
> posts on the internet concerning Ultraply,,some kind of supposed tobe
> good quality underlay plywood.(Still have to find out if it isa
> available in Canada ei specifically Edmonton area).Has anyone built
> boat with this stuff amonsght all of you fellows,ei;also awfullcurious
> about MDO...MikeHi Mike,
Cannot speak to your Ultraply query but can probably go on for ages
about MDO :-)
I have used it in the past for a MICRO I built(see files section in
the MICRO folder; Lenihan's MICRO) and continued using it during the
build of my Bolger WINDERMERE esturary cruiser.The best stuff I have
found is from Olympic ply,ex-Simpsonply, called SIGNAL MDO. Absolutely
great stuff,virtually no voids,waterproof glue between the laminates
and takes a finish like magic and much cheaper then marine ply. I am
sure if you drill around this group, via the search function, you'll
come up with lots of recommendations/discussions about the virtues of
MDO. Just be certain you are getting top quality MDO and stuff that
looks like it was wrapped in Kraft paper :-)
What are you looking to build with MDO?
Sincerely,
Peter Lenihan, a not too unbiased person regarding MDO, from along the
snow covered,swept and frozen shores of the St.Lawrence...........
>
Hi everybody an a happy New Year thrown in there also,,,Must be the
Scrooge in me, taking over my boat building urges...been chequing some
posts on the internet concerning Ultraply,,some kind of supposed to be
good quality underlay plywood.(Still have to find out if it is
available in Canada ei specifically Edmonton area).Has anyone built a
boat with this stuff amonsght all of you fellows,ei;also awfull curious
about MDO...Mike
Scrooge in me, taking over my boat building urges...been chequing some
posts on the internet concerning Ultraply,,some kind of supposed to be
good quality underlay plywood.(Still have to find out if it is
available in Canada ei specifically Edmonton area).Has anyone built a
boat with this stuff amonsght all of you fellows,ei;also awfull curious
about MDO...Mike