Glueing spars

[Brian Wood]

Anyone thought of gluing spars with TitebondIII?
Or have actually done it?

[JimConlin]

Don't some of the PVA glues creep?

[westinghouse]

I dunno about you guys south of the line, but now that we can't get uf109 around here it's time to start thinking about alternatives...TB3 - 'sat the brown one part polyurethane? I say go at it and report in a decade. If it's the polyurethane, I don't envy doing that job at all. Toss'll have an opinion, and he's nearby you. Sorry to waste time here if you've gone that route already.

[Brian Wood]

Titebond III is a poly vinyl acrylic that passes type I water resistance. The glue I wiped on my jeans has been there through 10 washings, still there. Our 1979 cedar strip canoe was glued up with Elmers pva. Of coarse it was covered with epoxy, but the in and outwale and the thwarts were just glued and varnished and are still together. Canoe is stored in a very damp shed and gets a good work out every summer. I think I would rather use a pva than a poly on a mast or boom. Has to be as water resistant as the Weldwood.

[Brian Palmer]

I glued up a 17 foot long and 2 1/4 diameter sprit out of 3 laminations of doug fir and Tite-bond III and after three seasons it is fine. It is stored under cover, however, and I used epoxy for the scarfs in the laminations to bring them up to 17 ft.

I also glued up a 13 foot oar from two laminations using TB III. It is one year old, and so far so good. it is also stored under cover.

-- Brian

[Bob Smalser]

Ever hear of a professional who uses PVA glues in spars?

How big are these spars and how much open time is needed during glueup?

These birdsmouth spars where gap-filling ability is important?

Planning on enuf scantling to plane off some creep in a few years?

Whatcha gonna fix a failed or damaged PVA joint with far in the future? More PVA?

http://www.woodcentral.com/cg i-bin/readarticle.pl?dir=smalser&file=articles_737.shtml (http://www.woodcentral.com/cgi-bin/readarticle.pl?dir=smalser&file=articles_737.shtml)

http://www.woodcentral.com/cg i-bin/readarticle.pl?dir=smalser&file=articles_605.shtml (http://www.woodcentral.com/cgi-bin/readarticle.pl?dir=smalser&file=articles_605.shtml)

Marine epoxy for birdsmouth spars and resorcinol, epoxy, or UF in box section spars remain the best choices. Poly's don't fill gaps well enough to be the best choice for birdsmouth spars...some of the new poly construction adhesives show some promise there but that remains inconclusive.

All are worthless if they tack up before you get your spar assembled....and that dilemma alone can eliminate PVA's and construction adhesives for your purpose and make epoxy, resorcinol and UF come back into their own.

[ 02-26-2006, 01:15 PM: Message edited by: Bob Smalser ]