I'm a hide glue novice and wanted to ask why (according to the Frank's glue chart) PVA glue would be preferred for back braces but hide glue for the front ones? I'm aware that the rigidity of hide glue is thought to enhance an instruments tone - so why not use it for back braces also? Is there any other application in lutherie where PVA (like LMI yellow glue) would be preferable to hide glue regarding wood-to-wood bonding performance? Thanks!
If you want to use HHG for everything, go ahead. It's what I do when I'm working on an instrument that was originally built using HHG but in the instances of a newer instrument there are some joints that I will sometimes use Titebond instead.
I think the idea behind Frank's chart (while not trying to put words in his mouth) is to give some idea of where he feels that HHG is a better choice if you are wanting the benefits without dedicating yourself to using it for the whole build.
If you haven't worked with it, there is a pretty good learning curve to get comfortable with it for everything. Large glue ups can be a trial because of the short work time. It's almost always a race to get the clamps in position before the glue sets too much. On almost any HHG glue up the clamps HAVE to be ready to go and a dry run or two is practically a requirement.
If you haven't used it at all, I recommend that you play around with it on some scrap to see how it works.
You're bang on, Ned!
I've seen countless glue failures with hot hide glue due to poor workmanship, ill-fitting joints, bad gluing and clamping technique.
Now, for the caps lock key:
IF YOU CHOOSE TO BELIEVE THAT HIDE GLUE CONTRIBUTES TO TONE, BE MY GUEST. I WILL NOT JOIN YOU AT THAT PARTY.
Hide glue does have other good qualities that make it the desirable glue for many traditional use: absolute resistance to creep, good heat tolerance, great longevity if used properly.
I think I may be quoting you on glue and tone comment. I've been of the same opinion for many years but being able to quote FF in this matter is of great value. I just don't command the degree of respect that Frank does, but I'm not bitter. Well, maybe a little.
Actually, no - not even a little. Thank you Mr. Ford - for everything. Your sharing of your vast knowledge both here and your other site continues to be in inspiration to all of us.
I second Ned's advice to play around with some scrap wood. It'll give you a very clear idea as to how long you can wait before applying the clamps, how much glue to put on, and how different types of wood react to it (hard vs. soft, dense vs. porous).
What I did was get some 1" wide and thick strips of wood and cut them down to 1ft length. Then glue them pairwise so that 6" of each strip is overlapping. Let it dry overnight. The next day I would stand on one end and push on the other with my other leg so it cracks. It won't tell you much about the strength of the glue or the joint (these are physically weak joints anyway), but it will tell you if your gluing was correct. What you want to see is wood failure. If the joint broke along the glue line, then it wasn't glued right (or the wood is very dense and requires a different approach than just putting glue on). If the wood failed then it was glued right.
For what its worth, that's the advice I got from the really nice guy (whose name I forgot) who works at Milligan & Higgins.
Thank you both for your insights - always something to learn!