Celluloid and corrosion

Heretic

Has anyone experienced celluloid pick guards reacting with the metal bits (nickel plated) causing surface fogging or corrosion?
Is there any way to stop this?

Bob Holo

...never heard of it as a topic of conversation, but I've definitely seen it on older guitars and just thought it was that the plating was giving up over time to the effects of sweat / nicotine etc... By older, I mean guitars in the 80 to 90 years range... world war 1 era... I guess it wouldn't surprise me if the celluloid is contributing to the plating's decay. (real) celluloid is made by nitrating cotton.. ie., soaking it in nitric & sulfuric acid ... rinsing in water & then mixing it with acetone or alcohol and ?? glycerin / camphor / urea ?? or a few other things of that sort... some things to give it a little flexibility and other things to keep it from blowing up... I mean it's essentially plasticized gunpowder... well, plasticized gun-cotton/primer at any rate. They used to make billiard balls from the stuff... Jesus... talk about incentive to not get the formulation wrong ;-) "That's quite an explosive break you have there, my good man." not exactly the most stable substance in the world and it does give off fumes that can degrade things... never really though about it too much but it wouldn't surprise me if it ate chrome.

So what to do about it? Typically interaction with air and acidic or basic contaminants speeds these things along... google around and see if you can find anyone talking about finishing vintage celluloid or otherwise preserving it... whether doing that would degrade the resale value... Clean the celluloid with deionized water and a mild detergent to remove contaminants - that will help. Perhaps wax it with a non-silicone based neutral-ph micro-crystaline wax like Renaissance, or if you can find precedence for doing it without ruining resale - perhaps even have the celluloid finished to slow air interaction even further. Wax is probably the least intrusive and won't chip away over time causing other problems. If it is a particularly old or valuable piece, there are people who specialize in this sort of thing... a museum in Germany has a huge collection of old guitars... can't remember the name... I believe there is a point of no return for celluloid... you want to delay it getting to that point through keeping it clean and waxed / finished etc... Once it begins to erupt... I think you're pretty much hosed and you need to get it away from the guitar or it'll start eating the finish too...

Heretic

Thanks for adding your thoughts, Bob. I was hoping you would. I had guessed about the release of nitric acid from my days of misspent youth. The out-gassing seems to particularly like to attack nickel plating and even draws out base copper from the brass below. Rather nasty really. Aside from keeping the instrument out of its case, I'm perplexed as how to keep this from happening.
The notion of an instrument out of its case, in a house with 2 siamese cats, is not a brilliant idea, but I think it might be the best solution. Barring that, I think if I keep the instrument under a bed with the lid propped open a bit, it just might work. I've read that Gretch guitars suffer from this reaction, as well, both from the pick guards and the bindings.