Re: PL Premium butt block failure
--- Inbolger@yahoogroups.com, fountainb@s... wrote:
I'm all with you on the epoxy in structural hull
components.However,it has been my experience when laminating large
flat panels that a) the grain will soak up alot/too much of the resin
(not good) and b) if the panels are bending around or over a
curve,then the pressure will squeeze out what little epoxy remains
(not good at all).
The hollowing I do on panels is relatively shallow and I do try to
pre wet the surfaces before going with a thickened batch of epoxy.
In Bruce Hectors case,trying to do a quick-n-dirty boat section with
PL,the slight hollow would at least help keep some of the PL in the
seam while the panel is bent to a curve and the joint becomes very
tight under pressure +/- 1/16".
Mind you,I've never worked with PL so alot of this is just
speculation on my part also :-)
Sincerely,
Peter Lenihan
> Not sure that this is an appropriate use of the famous Lenihanhollow
> joint.the
> I think these polyurethane glues need a tight joint, no? Otherwise
> gluerecycling
> foams up and has no strength. Not that I have ever used it, just
> boatbuilding lore.stuff,
>
> I would use epoxy for the hull and save the PL for less structural
> myself.Bruce,
> In which case I would certainly hollow the joint.
>
> Bruce Fountain
> Senior Software Engineer
> Union Switch & Signal
> Perth, Western Australia
I'm all with you on the epoxy in structural hull
components.However,it has been my experience when laminating large
flat panels that a) the grain will soak up alot/too much of the resin
(not good) and b) if the panels are bending around or over a
curve,then the pressure will squeeze out what little epoxy remains
(not good at all).
The hollowing I do on panels is relatively shallow and I do try to
pre wet the surfaces before going with a thickened batch of epoxy.
In Bruce Hectors case,trying to do a quick-n-dirty boat section with
PL,the slight hollow would at least help keep some of the PL in the
seam while the panel is bent to a curve and the joint becomes very
tight under pressure +/- 1/16".
Mind you,I've never worked with PL so alot of this is just
speculation on my part also :-)
Sincerely,
Peter Lenihan
I built a 20 inch square box from 2X6 spruce lumber to be used as a sift box for blasting sand. An employee (generic nose picker) backed into it with his truck. The PL and wood screw joints failed at the glueline and not at the fiber. (The employee got a week of unpaid vacation.)
PL seems to be a very good adhesive but as thick as it is I would not count on it for right angle joints. Long glue lines loaded in shear are probably fine.
Filleted joints need tensile strength. PL does not appear to be adaquate for this purpose. It just doesn't get the penetration of epoxy. Nor does it indicate good strength in tension.
Admittedly, my testing has been rather limited.
Doug
PL seems to be a very good adhesive but as thick as it is I would not count on it for right angle joints. Long glue lines loaded in shear are probably fine.
Filleted joints need tensile strength. PL does not appear to be adaquate for this purpose. It just doesn't get the penetration of epoxy. Nor does it indicate good strength in tension.
Admittedly, my testing has been rather limited.
Doug
Peter Lenihan wrote:
joint.
I think these polyurethane glues need a tight joint, no? Otherwise the
glue
foams up and has no strength. Not that I have ever used it, just recycling
boatbuilding lore.
I would use epoxy for the hull and save the PL for less structural stuff,
myself.
In which case I would certainly hollow the joint.
Bruce Fountain
Senior Software Engineer
Union Switch & Signal
Perth, Western Australia
> and the cure,to my way of thinking,is to apply the not-yet-world-Not sure that this is an appropriate use of the famous Lenihan hollow
> famous HOLLOW Trick.This would be particularly useful in any area
> where bending is expected to literally apply so much force between
> joined surfaces as to leave no glue whatsoever in between the pieces.
joint.
I think these polyurethane glues need a tight joint, no? Otherwise the
glue
foams up and has no strength. Not that I have ever used it, just recycling
boatbuilding lore.
I would use epoxy for the hull and save the PL for less structural stuff,
myself.
In which case I would certainly hollow the joint.
Bruce Fountain
Senior Software Engineer
Union Switch & Signal
Perth, Western Australia
--- Inbolger@yahoogroups.com, "Bruce Hector" <bruce_hector@h...> wrote:
CSB Pirogue. I'm using epoxy and fiberglass tape for the butt joints on the sides
and bottom. It's not the most complex boat construction, but everything is
holding well.
stern. The PL400 holds without complaint, weeks later.
floor screws held the parts together without too much squeezing. The result: the
joints are rock solid.
Altough I have every confidence in PL 400, and it hasn't shown me any
evidence otherwise, I'll be applying epoxy & wood flour fillets along interior
joints to ensure water tightness and add some strength. I'll also be sheathing
the chines with fiberglass and epoxy for abrasion resistance.
(Why did I choose PL 400 over PL Premium? Absent-mindedness. In my
reckless enthusiasm, I grabbed a few tubes of the Bulldog PL glue with the
highest number that was weatherproof, neglecting to see the tubes of PL
Premium at the bottom of the store shelf.)
Marc.
> Has anyone had a PL Premium glued, stressed joint fail before?I'm using PL 400 on the stem, stern, bulkheads, gunwales, and chine logs of my
CSB Pirogue. I'm using epoxy and fiberglass tape for the butt joints on the sides
and bottom. It's not the most complex boat construction, but everything is
holding well.
> The joint had cured for over 48 hours and when we removed the screwsWe did the same thing for the most stressed joints on the hull: the stem and
> holding the butt together, it sprang apart.
stern. The PL400 holds without complaint, weeks later.
> To be fair to PL, I don't see a lot of glue in there, so maybe I wentI agree with Peter Lenihan: glue starvation is the likeliest cause of failure.
> too light.
> My advice, is to be generous when using PL in stressed joints, and toI was generous at the stem and stern joints. And we made sure the temporary
> spread it with a notched spreader to form uniform trails of the glue
> 1/4 inch apart, to get a nice uniform bed of PL in the joint.
floor screws held the parts together without too much squeezing. The result: the
joints are rock solid.
Altough I have every confidence in PL 400, and it hasn't shown me any
evidence otherwise, I'll be applying epoxy & wood flour fillets along interior
joints to ensure water tightness and add some strength. I'll also be sheathing
the chines with fiberglass and epoxy for abrasion resistance.
(Why did I choose PL 400 over PL Premium? Absent-mindedness. In my
reckless enthusiasm, I grabbed a few tubes of the Bulldog PL glue with the
highest number that was weatherproof, neglecting to see the tubes of PL
Premium at the bottom of the store shelf.)
Marc.
I would not, under any circustances, use PL without a mechanical fastener as a backup. It just ain't that good despite all the high praises it gets in these forums. I'd say it's adequate as bedding/adhesive compound. Glue, it ain't.
The butts on my AF4 are glued with 5200 and backed up with lots of ring shank nails. And on the outside, there is a layer of glass, set in epoxy.
JB
-------Original Message-------
From: Bruce Hector <bruce_hector@...>
Sent: 07/07/03 01:25 PM
To:bolger@yahoogroups.com
Subject: [bolger] PL Premium butt block failure
sharpie bow module. These were in a straight section of the sides,
about 1 foot aft of the midships frame and 3 feet forward of the
transom.
I had noticed a LOT of stress to bow outwards at this joint when I
pulled in the bow to form the point. So much that I had to attach
some 2 by 2s to the inside and screw it tight to keep it straight and
square.
The joint had cured for over 48 hours and when we removed the screws
holding the butt together, it sparny apart.
To be fair to PL, I don't see a lot of glue in there, so maybe I went
too light. Perhaps I was nearing the end of a tube, I don't remember.
Now I'll inject epoxy and screw it together again, as well as sand a
little trough to add a few layers of FG cloth in epoxy without
creating a high spot on the hull side.
All the other joints are holding, including the one holding the
bottom to the bend forming the forward rocker, which is also under
stress as the ply obviously would like to bounce back flat.
My advice, is to be generous when using PL in stressed joints, and to
spread it with a notched spreader to form uniform trails of the glue
1/4 inch apart, to get a nice uniform bed of PL in the joint.
Or better yet, use epoxy in stressed joints. If this had sprung at
sea, the vessel could have foundered!
Bruce Hector
Carefully reading everything on the side of the PL tube and
scratching his head raw.
Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
- add your comments at the TOP and SIGN your posts and <snip> away
- To order 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
Your use of Yahoo! Groups is subject tohttp://docs.yahoo.com/info/terms/
The butts on my AF4 are glued with 5200 and backed up with lots of ring shank nails. And on the outside, there is a layer of glass, set in epoxy.
JB
-------Original Message-------
From: Bruce Hector <bruce_hector@...>
Sent: 07/07/03 01:25 PM
To:bolger@yahoogroups.com
Subject: [bolger] PL Premium butt block failure
>The butt blocks just failed and sprung open on both sides of the TIMS
> Has anyone had a PL Premium glued, stressed joint fail before?
sharpie bow module. These were in a straight section of the sides,
about 1 foot aft of the midships frame and 3 feet forward of the
transom.
I had noticed a LOT of stress to bow outwards at this joint when I
pulled in the bow to form the point. So much that I had to attach
some 2 by 2s to the inside and screw it tight to keep it straight and
square.
The joint had cured for over 48 hours and when we removed the screws
holding the butt together, it sparny apart.
To be fair to PL, I don't see a lot of glue in there, so maybe I went
too light. Perhaps I was nearing the end of a tube, I don't remember.
Now I'll inject epoxy and screw it together again, as well as sand a
little trough to add a few layers of FG cloth in epoxy without
creating a high spot on the hull side.
All the other joints are holding, including the one holding the
bottom to the bend forming the forward rocker, which is also under
stress as the ply obviously would like to bounce back flat.
My advice, is to be generous when using PL in stressed joints, and to
spread it with a notched spreader to form uniform trails of the glue
1/4 inch apart, to get a nice uniform bed of PL in the joint.
Or better yet, use epoxy in stressed joints. If this had sprung at
sea, the vessel could have foundered!
Bruce Hector
Carefully reading everything on the side of the PL tube and
scratching his head raw.
Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
- add your comments at the TOP and SIGN your posts and <snip> away
- To order 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
Your use of Yahoo! Groups is subject tohttp://docs.yahoo.com/info/terms/
>
One thing I have noticed about PL is that when gluing large flat surface
such as a butt joint, use the liquid form such as Elmers Polyurethane or
Gorrilla Glue and spread it out with a stir stick or slotted spreader, a lot
like you would epoxy. The PL Construction in a tube seems to hold as well
but it won't spread as easy across a large joint making for a glue starved
joint. Also, on critical joints use a water bottle and mist the wood first
if it's real dry, it helps with the ultimate joint strength.
With all that said, I'm using epoxy for splicing plywood on my Wyoming, I
just feel better about it all.
Jeff
such as a butt joint, use the liquid form such as Elmers Polyurethane or
Gorrilla Glue and spread it out with a stir stick or slotted spreader, a lot
like you would epoxy. The PL Construction in a tube seems to hold as well
but it won't spread as easy across a large joint making for a glue starved
joint. Also, on critical joints use a water bottle and mist the wood first
if it's real dry, it helps with the ultimate joint strength.
With all that said, I'm using epoxy for splicing plywood on my Wyoming, I
just feel better about it all.
Jeff
----- Original Message -----
From: "Peter Lenihan" <ellengaest@...>
To: <bolger@yahoogroups.com>
Sent: Monday, July 07, 2003 11:38 AM
Subject: [bolger] Re: PL Premium butt block failure
> --- Inbolger@yahoogroups.com, "Bruce Hector" <bruce_hector@h...>
> wrote:
> Bos'sun Bruce,
> Sorry to hear about the joint failure. Since you mention that the
> other joints are holding up perhaps there is a more subtle thing
> going on.Namely.....glue starvation! Yup.that's what I think it is
> and the cure,to my way of thinking,is to apply the not-yet-world-
> famous HOLLOW Trick.This would be particularly useful in any area
> where bending is expected to literally apply so much force between
> joined surfaces as to leave no glue whatsoever in between the pieces.
> Check it out in the files section under shop tips(i think?).It will
> work with two plywood panels as I have done everywhere so far on
> WINDERMERES bottom,centerboard,centerboard box and cheek pieces.If it
> still fails then PL simply ain't up to the job.
> Best of luck with the remedy!!
>
> Sincerely,
> Peter Lenihan,soon to be TIMs section builder and who knows
> nuttin' 'bout PL other then it being my initials,from along the
> shores of the St.Lawrence............
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - add your comments at the TOP and SIGN your posts and <snip> away
> - To order 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
>
> Your use of Yahoo! Groups is subject tohttp://docs.yahoo.com/info/terms/
>
>
--- Inbolger@yahoogroups.com, "Bruce Hector" <bruce_hector@h...>
wrote:
Bos'sun Bruce,
Sorry to hear about the joint failure. Since you mention that the
other joints are holding up perhaps there is a more subtle thing
going on.Namely.....glue starvation! Yup.that's what I think it is
and the cure,to my way of thinking,is to apply the not-yet-world-
famous HOLLOW Trick.This would be particularly useful in any area
where bending is expected to literally apply so much force between
joined surfaces as to leave no glue whatsoever in between the pieces.
Check it out in the files section under shop tips(i think?).It will
work with two plywood panels as I have done everywhere so far on
WINDERMERES bottom,centerboard,centerboard box and cheek pieces.If it
still fails then PL simply ain't up to the job.
Best of luck with the remedy!!
Sincerely,
Peter Lenihan,soon to be TIMs section builder and who knows
nuttin' 'bout PL other then it being my initials,from along the
shores of the St.Lawrence............
wrote:
Bos'sun Bruce,
Sorry to hear about the joint failure. Since you mention that the
other joints are holding up perhaps there is a more subtle thing
going on.Namely.....glue starvation! Yup.that's what I think it is
and the cure,to my way of thinking,is to apply the not-yet-world-
famous HOLLOW Trick.This would be particularly useful in any area
where bending is expected to literally apply so much force between
joined surfaces as to leave no glue whatsoever in between the pieces.
Check it out in the files section under shop tips(i think?).It will
work with two plywood panels as I have done everywhere so far on
WINDERMERES bottom,centerboard,centerboard box and cheek pieces.If it
still fails then PL simply ain't up to the job.
Best of luck with the remedy!!
Sincerely,
Peter Lenihan,soon to be TIMs section builder and who knows
nuttin' 'bout PL other then it being my initials,from along the
shores of the St.Lawrence............
Has anyone had a PL Premium glued, stressed joint fail before?
The butt blocks just failed and sprung open on both sides of the TIMS
sharpie bow module. These were in a straight section of the sides,
about 1 foot aft of the midships frame and 3 feet forward of the
transom.
I had noticed a LOT of stress to bow outwards at this joint when I
pulled in the bow to form the pointy end. So much that I had to
attach some 2 by 2s to the inside and screw it tight to keep it
straight and square.
The joint had cured for over 48 hours and when we removed the screws
holding the butt together, it sprang apart.
To be fair to PL, I don't see a lot of glue in there, so maybe I went
too light. Perhaps I was nearing the end of a tube, I don't remember.
But a good sized bead of PL squeezed out of the joint between the two
sheets and had to be sanded off.
Now I'll inject epoxy and screw it together again, as well as sand a
shallow trough to add a few layers of FG cloth set in epoxy without
creating a high spot on the hull side.
All the other joints are holding, including the one holding the
bottom to the bend forming the forward rocker, which is also under
stress as the ply obviously would like to bounce back flat.
My advice, is to be generous when using PL in stressed joints, and to
spread it with a notched spreader to form uniform trails of the glue
1/4 inch apart, to get a nice uniform bed of PL in the joint.
Or better yet, use epoxy in stressed joints. If this had sprung at
sea, the vessel could have foundered!
Bruce Hector
http://www.brucesboats.com
Carefully reading everything on the side of the PL tube and
scratching his head raw on the shores of Lake Ontario.
The butt blocks just failed and sprung open on both sides of the TIMS
sharpie bow module. These were in a straight section of the sides,
about 1 foot aft of the midships frame and 3 feet forward of the
transom.
I had noticed a LOT of stress to bow outwards at this joint when I
pulled in the bow to form the pointy end. So much that I had to
attach some 2 by 2s to the inside and screw it tight to keep it
straight and square.
The joint had cured for over 48 hours and when we removed the screws
holding the butt together, it sprang apart.
To be fair to PL, I don't see a lot of glue in there, so maybe I went
too light. Perhaps I was nearing the end of a tube, I don't remember.
But a good sized bead of PL squeezed out of the joint between the two
sheets and had to be sanded off.
Now I'll inject epoxy and screw it together again, as well as sand a
shallow trough to add a few layers of FG cloth set in epoxy without
creating a high spot on the hull side.
All the other joints are holding, including the one holding the
bottom to the bend forming the forward rocker, which is also under
stress as the ply obviously would like to bounce back flat.
My advice, is to be generous when using PL in stressed joints, and to
spread it with a notched spreader to form uniform trails of the glue
1/4 inch apart, to get a nice uniform bed of PL in the joint.
Or better yet, use epoxy in stressed joints. If this had sprung at
sea, the vessel could have foundered!
Bruce Hector
http://www.brucesboats.com
Carefully reading everything on the side of the PL tube and
scratching his head raw on the shores of Lake Ontario.
Has anyone had a PL Premium glued, stressed joint fail before?
The butt blocks just failed and sprung open on both sides of the TIMS
sharpie bow module. These were in a straight section of the sides,
about 1 foot aft of the midships frame and 3 feet forward of the
transom.
I had noticed a LOT of stress to bow outwards at this joint when I
pulled in the bow to form the point. So much that I had to attach
some 2 by 2s to the inside and screw it tight to keep it straight and
square.
The joint had cured for over 48 hours and when we removed the screws
holding the butt together, it sparny apart.
To be fair to PL, I don't see a lot of glue in there, so maybe I went
too light. Perhaps I was nearing the end of a tube, I don't remember.
Now I'll inject epoxy and screw it together again, as well as sand a
little trough to add a few layers of FG cloth in epoxy without
creating a high spot on the hull side.
All the other joints are holding, including the one holding the
bottom to the bend forming the forward rocker, which is also under
stress as the ply obviously would like to bounce back flat.
My advice, is to be generous when using PL in stressed joints, and to
spread it with a notched spreader to form uniform trails of the glue
1/4 inch apart, to get a nice uniform bed of PL in the joint.
Or better yet, use epoxy in stressed joints. If this had sprung at
sea, the vessel could have foundered!
Bruce Hector
Carefully reading everything on the side of the PL tube and
scratching his head raw.
The butt blocks just failed and sprung open on both sides of the TIMS
sharpie bow module. These were in a straight section of the sides,
about 1 foot aft of the midships frame and 3 feet forward of the
transom.
I had noticed a LOT of stress to bow outwards at this joint when I
pulled in the bow to form the point. So much that I had to attach
some 2 by 2s to the inside and screw it tight to keep it straight and
square.
The joint had cured for over 48 hours and when we removed the screws
holding the butt together, it sparny apart.
To be fair to PL, I don't see a lot of glue in there, so maybe I went
too light. Perhaps I was nearing the end of a tube, I don't remember.
Now I'll inject epoxy and screw it together again, as well as sand a
little trough to add a few layers of FG cloth in epoxy without
creating a high spot on the hull side.
All the other joints are holding, including the one holding the
bottom to the bend forming the forward rocker, which is also under
stress as the ply obviously would like to bounce back flat.
My advice, is to be generous when using PL in stressed joints, and to
spread it with a notched spreader to form uniform trails of the glue
1/4 inch apart, to get a nice uniform bed of PL in the joint.
Or better yet, use epoxy in stressed joints. If this had sprung at
sea, the vessel could have foundered!
Bruce Hector
Carefully reading everything on the side of the PL tube and
scratching his head raw.