Official Luthiers Forum!
http://www-.luthiersforum.com/forum/

Gluing question
http://www-.luthiersforum.com/forum/viewtopic.php?f=10101&t=42327		 Page 1 of 1
Author:  Paul Eisen [ Sun Dec 29, 2013 1:28 am ]
Post subject:  Gluing question
Hi folks,

I just saw a youtube video series on building an ES 335 type guitar. Overall, I think I learned a lot from watching it, but the luthier used a gluing technique I've never seen before. First, he used a lot of glue. I'm talking puddles of the stuff. Second, he applied glue to both sides of the joint. Is it a good idea to put glue on both sides? If so, why? It seems to me that as soon as I put the joint together, glue is going to be on both pieces. Also, is there any reason to use lakes of glue (most of which is going to get squeezed out or wiped off)? am relatively new to woodworking, having just discovered a few weeks ago which end of the chisel is supposed to be sharp. So I don't know these things.

--Paul
Author:  DennisK [ Sun Dec 29, 2013 1:57 am ]
Post subject:  Re: Gluing question
How much glue: Depends on the situation. I usually aim for just enough to get a bead of squeeze-out all around, but not a big mess. But err on the side of a big mess. And for hide glue rub joints, you do want a good puddle to create the suction that clamps the joint (once you get that established, you can clean up the puddle, which is easy once it gels)

Glue on both sides... I don't see why it would be necessary. When gluing headstock scarf joints, I apply the glue to the 15 degree cut surface so it has time to soak into the partial endgrain as much as possible before I squeeze it out. But if I was really worried, I'd give that surface a wash coat of thin hide glue and let it dry before doing the actual gluing.

Here's an interesting test case I did recently... I had some 8" wide giant sequoia offcuts that were a little too short to really make anything with, so I tried scarf jointing them together lengthwise to make an ukulele top. The first time, I flexed the plate a bit and it popped apart pretty easily (joint starvation, glue sucked into the endgrain of the 15-20 degree surfaces). But I just added some more hide glue and re-clamped it, and after cutting out the shape, I tried breaking one of the offcuts to see if it was still too fragile to use. Surprisingly, the joint was actually stronger than the wood this time! Granted, giant sequoia is super soft, so I doubt you could get comparable strength to rosewood, for example. But it's most certainly adequate for an ukulele soundboard.
Attachment:
SoundboardTest.jpg
Author:  Paul Eisen [ Sun Dec 29, 2013 7:47 pm ]
Post subject:  Re: Gluing question
Thanks for the responses. I see I have some experiments to run. My current method is to put enough on one side so I can smear a thin translucent layer. Then I put the other piece on and clamp until I see squeeze-out. But I can see where doing this on end grain could be problematic.

Thanks again!

--Paul
Author:  Link Van Cleave [ Mon Dec 30, 2013 4:54 pm ]
Post subject:  Re: Gluing question
Todd Stock wrote:
For AR/PVA, I coat both surfaces...porous, open grained wood can suck up a lot of glue, so the idea is to get both surfaces coated, then add glue if needed. Also think that is the general recommendation from manufacturers as well. For hide and fish, I coat both surfaces of bridge and fretboard joints, as those are usually glued warm and I want as much glue in the joint as possible. Most woodworkers plan to have just a bit of squeeze-out on AR/PVA glues, while hide and fish users tend to go for more...I think this is more an issue of clean-up than any real difference in the glues...hide is much easier to clean up than fish, and fish is easier to clean than Titebond or LMI White.


What he said.
Page 1 of 1 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/