Official Luthiers Forum!

I'm planning to build a small vacuum frame for a bridge glue-up. The 3/8" closed cell gasket I'm using is going to be cut from a sheet of what I was told is neoprene rubber for a seamless gasket.
The soundboard will have a nitro lacquer finish on it.
My question is there a problem with nitro and neoprene reaction? I've heard the stories about vinyl so I don't want to take a chance.
I know there's folks out there that use vacuum and would really rather do that than go the C clamp route.
Btw, I will be using hide glue and plan to clamp about an hour.
Thanks


Sent from my iPhone using Tapatalk 2

I think you need to do a test on scrap, that's the best way to be sure. I think neopreme is OK with lacquer, but there's several flavors of each of these materials, so your best route is to test what you have.

_________________
A man hears what he wants to hear, and disreguards the rest. Paul Simon

Neoprene is the typical sponge rubber used on guitar stands so it's a fairly safe assumption you're ok. I can't imagine there would be a reaction without a solvent present. ...testing wouldn't hurt anything.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Since you will only have one hour of contact you should have no problems. The problem occurs when lacquer is in contact with the vinyl for days or weeks at a time.

With a new build and fresh lacquer, there will still be a small amount of solvent outgassing, and the contact time for reaction to occur will be at a minimum. I agree you're probably OK with an hour or two, but the risk of having to sand and refinish the top would induce me to do the test.

_________________
A man hears what he wants to hear, and disreguards the rest. Paul Simon

Make sure the lacquer is fully cured and rock hard before you vacuum-press glue the bridge on, otherwise the force of the vacuum will mark the finish where the seal touches it.
DAMHIKT....

Dave F.

_________________
Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

Hey guys,
Thanks much and I agree a test sample is a good idea. Dave - thanks, I hadn't thought of that.
One more thing i overlooked is the membrane I got from Joewoodworker is polyurethane if I'm remembering right. I'll have to see how that will react with nitro, it looks a lot like vinyl. Hope it's ok, i sure do like vacuum.


Sent from my iPhone using Tapatalk 2