Acoustic Guitar Construction

I clamp up overnight, so that's not a problem. And for this particular top, this is the best glue.

Read this:


http://fretsnet.ning.com/forum/topics/fishy-solution

I am having some dialog with my Martin factory contacts in engineering and the Custom Shop on the topic of glue and torrefied wood. Interesting so far I will summarize when all the questions are addressed. Two things so far --- they do not use fish glue --- and yes there is a concern for the top surface torrefied fibers pulling off, it is not a glue failure, but rather wood delamination.

Ok, I'm wrong. But everything is glued together so I'm going with it. Of course I have the bridge to glue yet, but since people have had popoffs with TB, and not with Fish, I'll probably go with the Fish here too.
The one guy who uses a lot of torrefied is Dana Bourgois, and his shop foreman told me that only fish glue, with heating before hand, gives them the most confidence.
Dan may not know about the lamination of the torrefied wood. Beats me.

Seems there is a lot to learn (who knows what's right or wrong?) not only about fish glue but the torrefaction process as well --- there seems to be no standard for "converting" the soundboards, I find that troubling even in our hobby. These "wood glue" failure events to me point toward the need for a science review to determine cause and affect. Nice that warmed up fish glue "seems" to work OK --- WHY? Is it strictly a mechanical bond? --- - but what the hell, you can't glue this processed material with the best PVA "wood glue" on the planet?

Part of my Martin inquiry is with the repair techs as well --- to see what is being fed to the field.

Listen here, Cierp, and listen good: when I tap a bottle of fish glue, it rings for minutes. When I tap a bottle of your fancy-pants PVA, all I get is a thud.
Case closed. There's your science. Bam!!

All in jest of course.

Ken - have you heard anything more from the Martin techs?

I've been thinking - this can be both a glue issue and a lamination/process issue. That is, given the fact of a particular top, in this case 'torrefied' - a guy has to decide what to do with it - and if fish glue has turned out to be the best, by the accounts of those who have used it on this wood, then so be it. It does not address the question of the method of torrefication, but works with as best it can.

Martin uses Franklin Assembly 65 and HHG --- here's the caveat, and my point on the matter, Martin has two very specific levels of the torrifaction process. Time, temperature, atmosphere nothing in between. So they know exactly what to expect in their assembly process. There is no industry standard -- so how does the small shop know what they are using and what is the proper adhesion chemistry?