Nitro Checking

[Flight959]

Guys,

 

I was given an acoustic from 1966 (Not Gibson) which is a spanish/classical guitar. The guitar has a Rosewood Fretboard with solid spruce top and a really nice grained Mahogany back. The guitar has some serious checking on the top. Is it just the nitrocellulose lacquer that Gibson uses that checks? or do other finishes do it too?

 

Do other guitar companies use nitrocellulose finish..

 

It looks really smart...

 

Flight959

[chongo]

Guys' date='

 

I was given an acoustic from 1966 (Not Gibson) which is a spanish/classical guitar. The guitar has a Rosewood Fretboard with solid spruce top and a really nice grained Mahogany back. The guitar has some serious checking on the top. Is it just the nitrocellulose lacquer that Gibson uses that checks? or do other finishes do it too?

 

Do other guitar companies use nitrocellulose finish..

 

[/quote']

 

Most companies no longer use nitrocellulose lacquer. The solvents in it are damaging to the environment and they're dangerous to employees. The finish continues to outgas solvents and eventually becomes brittle. It's vulnerable to softening by some chemicals (including those in certain rubbers on some guitar stands) and it checks easily when guitars expand and contract with temperature and humdity changes.

 

Some misguided guitar players think that the finish is thinner than others because as it ages, it shrinks and shows the grain structure underlying the layer of lacquer. Truth is, it doesn't matter how thick the layer of lacquer is, this "imprinting" will still show through, and has driven car restorers and builders fits for years, until the EPA demanded that manufacturers drop solvent-based lacquers for cars in the early '90's. After some fits and starts with crappy formulations, car manufacturers now use water-based self-catalyzing formulas that last longer, are better for the environment and employees who have to work with them, and which have better "fill" qualities (don't shrink as much and don't show the underlying textures through the paint job). These can actually be applied *thinner* than the old nitrocellulose lacquers and can be applied as nearly 100% solids (to make drying times faster and paint jobs more accurate).

 

Gibson still uses the stuff because there are guitar players who think that it somehow contributes to the tone of their guitars despite all evidence to the contrary.

[80LPC]

All nitrocellulose lacquer checks. In addition to movement related cracking, it slowly decomposes releasing nitric acid, and turns yellow. It was used throughout the 20th century for finishing guitars. Here's a refinishing expert's view. http://www.fretnotguitarrepair.com/finishes.htm

[Thundergod]

What manner of trickery be this?

[pippy]

What manner of trickery be this?

 

'Tis Alchemy in it's truest form, TG; - Turning 'Base Coats' to Gold!!!!!! (exit, right, laughing like a 'Loon.........HaHaHaHahhhahahhahhahhaahhhahhah.....

[bobv]

Flight, yes it was common for most musical instrument makers in that era to use nitrocellulose. In fact, most twentieth century furniture is made with it. Its very forgiving to spray and the results are rather amazing especially in a production environment. Solid colors are another story since they started using Dupont car paints, which were an acrylic lacquer (still using a similar set of nasty solvents). One thing that's nice about nitro (maybe the only thing in my opinion, for what it's worth) is that it is very easy to spot repair since new lacquer melts in to the old stuff and you can't see where the line is (unlike painting a wall where you have to keep a "wet edge" or the transition shows up). There are new water based finishes that have that "burn-in" capability, but I digress. The point is, that if the crazing bothers you it is possible to have the guitar oversprayed with butyl cellusolve (I think that's what it's called) which will dissolve or melt the finish - just a little - and allow it to flow out and re-amalgamate. Sometimes a fresh coat lightly sprayed over the top will also cure the situation. You can't be sure at this point if the "weather checking" occurred slowly over many seasons of humidity changes, or whether some dope left it in the trunk in zero degree weather and opened the case immediately and sat down by the fireplace for a little jam.

 

 

Now, as for Chongo's well-informed post, I'm afraid that's going to fall on deaf ears. After all, we've already convinced ourselves how much a thin-skinned nitro finish improves tone, haven't we? If I hear one more pundit promising how much lacquer lets a guitar "breathe," I swear I'm going to stop visiting forums altogether (That was hyperbole, so don't test me on it, please).

[anothersixstringer]

So, the "Breathing" is not true ???

Only thing I know to be true is that the you can smell the wood through the nitro....er...it was the wood, wasn't it???

:0

[callen3615]

pics??

[Flight959]

pics??

 

I will put some on later today..

 

Flight959

[80LPC]

Solid colors are another story since they started using Dupont car paints' date=' which were an acrylic lacquer ).[/quote']

 

Not sure about Gibson, but Fender were using Duco (Dupont's brand name for nitrocellulose). There was a gradual switch to acrylic as new colours became availabe from '56. Fender continued to use certain colours in nitro, but regardless of paint type, the clear coat was still nitrocellulose.

 

http://www.provide.net/~cfh/fenderc.html