Comment

Comment by sanderson on August 2, 2009 at 11:20am

here is the article

Comment by Randy Dersham on August 1, 2009 at 8:00am

I think Sanderson will post a link to the Fine Woodworking article that tested a bunch of glues and epoxy on joints. It is very interesting. Bottom line is that epoxy and Tightbond III came out on top.

Below is a link to a CLC forum post about the same subject. There are two issues where epoxy is superior over Tightbond III, gap filling properties of thickened epoxy and the fact that epoxy soaked into the wood will blend with other applications of epoxy for a bright finished boat while Tightbond III will discolor (or actually not allow later applications of epoxy or varnish to soak into the wood leaving light spots) or not allow the wood to color with later applications of varnish.

http://www.clcboats.com/forum/5/thread/4925.html

RE: Gorilla glue vs. epoxy for scarf joints
» Submitted by George K - Wed, June 24 » 11:52 AM
The main reason I can come up with to stick with epoxy over TB is for appearance of a bright finish. If you don't get all the TB wiped off the surfaces before it cures it will not allow the epoxy to soak in like the surrounding wood when you glass the boat and you'll see blotchy areas at the scarfs.
George K
RE: Gorilla glue vs. epoxy for scarf joints
» Submitted by Laszlo - Wed, June 24 » 7:16 AM
Strength is not the issue with Titebond III vs. epoxy. It's plenty strong, the wood will break before the glue joint fails.
Thickened epoxy glue's main advantage is that it's gap-filling. You can get away with a less-than-perfect fit between the pieces and still get a perfect scarf. With TBIII and other glues a void will leave a weak spot that can become the starting point for fatigue failure.
Another possible issue is water. Epoxies are waterproof, TBIII is water resistant, albeit very water resistant. For use in the inside of a glassed and epoxied panel, this is not an issue unless the epoxy barrier gets damaged. Even then, TBIII's water resistance is such that there shouldn't be a problem as long as the damage gets repaired in a reasonable amount of time.
So it should work just fine for scarfing.
Laszlo

Comment by Jason Knight on July 31, 2009 at 7:25am

If epoxy joints have the strength that all these other glues are trying to replicate - why not just use epoxy? Is it an ease of use issue?

Comment by lhedrick on July 30, 2009 at 8:27pm

A lot has been written on the subject of glue. The new franklin titebone III waterproof glues can be used in place of epoxy for most tight joints. For end grain, joints with gaps and plywood scarfs I would still stick with epoxy.

From the test joints I have done I prefer the waterproof titebond PVA glue.

Comment by sanderson on July 29, 2009 at 11:45pm

its water resistant not waterproof if you want your boat to last more than one season i would use epoxy

Comment by eric stevens on July 29, 2009 at 5:47pm

I tried Gorilla glue and it was very strong, untill the wood was flexed and then it failed. Its realy strong compared to wood glue, but not even close to epoxy. I wouldnt risk the whole project on inferior glue.