Re: [bolger] Re: Torturing MDO
There isn't any magic, though there could be a fair
amount of confusion. The question would be what are
you scantling it for? stiffnees, rub resistance,
impact... If this is the shear panel, then possibly
stiffness would be near enough. The Gougeons caution
against assuming glass will magically outperform wood,
and recomend thickness for thickenss substitution.
One thing you can do is take a notched trowel, and
trowel on a thick enough coat of whatever to create
the sort of build you need for 1/4". Use a fairing,
or light filleting compound, this fairs easily because
the notched surface is half air. Either put glass
righ over the top as though it was a core, or take a
fill coat of something like 410. You now have a
microballon core material, and you can glass with 6
OZ. I came up with this approach after looking at how
they recomend fairing Baltek Duracore.
A few years ago, I went and inspected both the
Gougeon's Ollie, and Addagio. Addagio (voted by Sail
Magazine one of the top boats of the 20th century or
something) at 35' was made up of 7mm plywood, which is
pretty light. It needed to be because they tortured
the whole hull out of it. To reinforce it, they just
air stappled a mass of little ribs on the inside sort
of pencil thickness, and about 3" appart. I would
have to look the detail up. The Gougeons are high
tech, but their inspiration is basically the birch
bark canoe.
You can, of course, use balsa core. 1/4" of that
between 1/8" doorskins would have certain higher
properties than plywood. You can bag that kind of
material. I have done it with a shopvac. Another
option is the doorskin, and balsa, and a skin of
triaxial.
Lots of options
---pvanderw@...wrote:
<HR>
<html><body>
<tt>
<BR>
I wonder what the recommendations would be for
building that panel <BR>
with a 1/4 ply core and glass cloth inside and out,
per Jacques <BR>
Mertens. Jacques keeps his "scantling rule"
proprietary but I would <BR>
guess that it would run to the ply plus one layer of
fairly heavy <BR>
cloth inside and out. Seems like it might be easier to
me.<BR>
<BR>
Peter<BR>
<BR>
</tt>
<br>
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amount of confusion. The question would be what are
you scantling it for? stiffnees, rub resistance,
impact... If this is the shear panel, then possibly
stiffness would be near enough. The Gougeons caution
against assuming glass will magically outperform wood,
and recomend thickness for thickenss substitution.
One thing you can do is take a notched trowel, and
trowel on a thick enough coat of whatever to create
the sort of build you need for 1/4". Use a fairing,
or light filleting compound, this fairs easily because
the notched surface is half air. Either put glass
righ over the top as though it was a core, or take a
fill coat of something like 410. You now have a
microballon core material, and you can glass with 6
OZ. I came up with this approach after looking at how
they recomend fairing Baltek Duracore.
A few years ago, I went and inspected both the
Gougeon's Ollie, and Addagio. Addagio (voted by Sail
Magazine one of the top boats of the 20th century or
something) at 35' was made up of 7mm plywood, which is
pretty light. It needed to be because they tortured
the whole hull out of it. To reinforce it, they just
air stappled a mass of little ribs on the inside sort
of pencil thickness, and about 3" appart. I would
have to look the detail up. The Gougeons are high
tech, but their inspiration is basically the birch
bark canoe.
You can, of course, use balsa core. 1/4" of that
between 1/8" doorskins would have certain higher
properties than plywood. You can bag that kind of
material. I have done it with a shopvac. Another
option is the doorskin, and balsa, and a skin of
triaxial.
Lots of options
---pvanderw@...wrote:
<HR>
<html><body>
<tt>
> Might have worked better with regular 1/2"ply, or one sided MDO. <BR>
<BR>
I wonder what the recommendations would be for
building that panel <BR>
with a 1/4 ply core and glass cloth inside and out,
per Jacques <BR>
Mertens. Jacques keeps his "scantling rule"
proprietary but I would <BR>
guess that it would run to the ply plus one layer of
fairly heavy <BR>
cloth inside and out. Seems like it might be easier to
me.<BR>
<BR>
Peter<BR>
<BR>
</tt>
<br>
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<tt>
Bolger rules!!!<BR>
- no cursing, flaming, trolling, spamming, or flogging
dead horses<BR>
- pls take "personals" off-list, stay on
topic, and punctuate<BR>
- add your comments at the TOP and SIGN your posts,
snip all you like<BR>
- To order plans: Mr. Philip C. Bolger, P.O. Box 1209,
Gloucester, MA, 01930, Fax: (978) 282-1349<BR>
- Unsubscribe:
bolger-unsubscribe@yahoogroups.com</tt>
<br>
<br>
<tt>Your use of Yahoo! Groups is subject to the <a
href="http://docs.yahoo.com/info/terms/">Yahoo! Terms
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</br>
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_______________________________________________________
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> Might have worked better with regular 1/2" ply, or one sided MDO.I wonder what the recommendations would be for building that panel
with a 1/4 ply core and glass cloth inside and out, per Jacques
Mertens. Jacques keeps his "scantling rule" proprietary but I would
guess that it would run to the ply plus one layer of fairly heavy
cloth inside and out. Seems like it might be easier to me.
Peter
ME TOO!
Peter Lenihan
Peter Lenihan
--- In bolger@y..., "Orr, Jamie" <jorr@b...> wrote:
>
> Looking forward to the pictures.
>
> Jamie Orr
>
> -----Original Message-----
> From: richard@s... [mailto:richard@s...]
> Sent: October 18, 2001 8:44 AM
> To: bolger@y...
> Subject: [bolger] Torturing MDO
>
>
> Could have went with two layers of 1/4", but I already had the 1/2",
> couldn't think of a good way to clamp the two pieces together to get
> a good lamination without drilling hundreds of holes, and was
curious
> how much bend a piece of 1/2" ply would make before it broke!
As one who went with two layers of 1/4 ", I can confirm it takes a lot of
holes -- 386 if my memory serves, all of which had to be drilled, screwed,
unscrewed, filled and faired.
On the other hand, it allowed easy fitting of the bilges, they could be
taken on and off for trimming for an exact fit. And there's less stress on
the builder too!
Looking forward to the pictures.
Jamie Orr
-----Original Message-----
From:richard@...[mailto:richard@...]
Sent: October 18, 2001 8:44 AM
To:bolger@yahoogroups.com
Subject: [bolger] Torturing MDO
Could have went with two layers of 1/4", but I already had the 1/2",
couldn't think of a good way to clamp the two pieces together to get
a good lamination without drilling hundreds of holes, and was curious
how much bend a piece of 1/2" ply would make before it broke!
holes -- 386 if my memory serves, all of which had to be drilled, screwed,
unscrewed, filled and faired.
On the other hand, it allowed easy fitting of the bilges, they could be
taken on and off for trimming for an exact fit. And there's less stress on
the builder too!
Looking forward to the pictures.
Jamie Orr
-----Original Message-----
From:richard@...[mailto:richard@...]
Sent: October 18, 2001 8:44 AM
To:bolger@yahoogroups.com
Subject: [bolger] Torturing MDO
Could have went with two layers of 1/4", but I already had the 1/2",
couldn't think of a good way to clamp the two pieces together to get
a good lamination without drilling hundreds of holes, and was curious
how much bend a piece of 1/2" ply would make before it broke!
Well, finaly got the bilge panels on the Chebacco LC bent into shape.
There is about a 60 degree twist in a few feet. Tremendous amount of
energy stored in that twisted wood. I'm going to have to fillet and
glass all the joints in the front before I can remove the ropes.
Pulled them together with two piece of 5mm spectra and one piece of
5/16" braided poly. Twist, untwist one and take up the slack,
retwist, untwist a different one and take up the slack, etc.
At on point I heard cracking sounds, but I think it was the spectra
digging into the MDO.
Might have worked better with regular 1/2" ply, or one sided MDO. My
standard trick to make bent laminations is to get them wet to make
the bending easier. Paper face on the MDO prevented the water from
getting to the wood, so I had to twist this one dry.
Could have went with two layers of 1/4", but I already had the 1/2",
couldn't think of a good way to clamp the two pieces together to get
a good lamination without drilling hundreds of holes, and was curious
how much bend a piece of 1/2" ply would make before it broke!
Took pictures, will post them in the next issue of Chebacco.
There is about a 60 degree twist in a few feet. Tremendous amount of
energy stored in that twisted wood. I'm going to have to fillet and
glass all the joints in the front before I can remove the ropes.
Pulled them together with two piece of 5mm spectra and one piece of
5/16" braided poly. Twist, untwist one and take up the slack,
retwist, untwist a different one and take up the slack, etc.
At on point I heard cracking sounds, but I think it was the spectra
digging into the MDO.
Might have worked better with regular 1/2" ply, or one sided MDO. My
standard trick to make bent laminations is to get them wet to make
the bending easier. Paper face on the MDO prevented the water from
getting to the wood, so I had to twist this one dry.
Could have went with two layers of 1/4", but I already had the 1/2",
couldn't think of a good way to clamp the two pieces together to get
a good lamination without drilling hundreds of holes, and was curious
how much bend a piece of 1/2" ply would make before it broke!
Took pictures, will post them in the next issue of Chebacco.