best way to dissolve celluloid

[toddr]

i need to fill some spots where there is a little gap between the binding and the sides. i have used cyano to dissolve binding that i used for filler before and it looked a little transparent or discolored after sanding. will acetone do a better job?

[Chris Baird]

Acetone works but to get a good solid white(ish) color the melted binding has to be almost dry again. I have a bunch in a bottle that is fairly wet. When I use it I take some out and let it dry out for a bit. Once it is on the verge of being too firm I'll take it and mash it into the gap. Make sure your fingers or whatever are clean because the melted binding sucks dirt off anything and discolors.

[Plinky]

Talk about reviving an old thread - :))

My celluloid question concerns an old Kay guitar that I just bought - sorry to pollute the mando world with anything less than 8 strings.

BUT.... I've been searching the Kay people, the chemistry folk, antique doll people, film restoration....

My dilemma is this: The old Kay faux tortoise shell pick guard is warped and brittle, and in about 5 intact but cracked and crazed pieces. What I'd like to try and do is soften the whole pick shield and get it to lay flat like it should - Then I'd like to somehow encase it in clear epoxy in an attempt to "salvage" it - keeping it's funk intact.

Is it possible to use acetone to do this with out utterly destroying it?
Does it re-harden after treating with the acetone? And is it somewhat "renewed" (as in less brittle, and will the crazing fuse together)?

Included is a pic - before removal - It's held on by 3 screws. It pretty well shattered when it came off.

THANKS for ANY insight. No one else has any answer yet. (although the doll lady had a great article on repairing a celluloid dolls head - :)

[Michael Lewis]

Harmony guard held on with 3 screws, I would bet it is styrene, not celluloid. I think your idea of using epoxy is a good one if you want to keep the original guard. I would flatten the guard by crushing it to pieces and use the epoxy to hold everything in place. Otherwise you are looking at making a new guard, which is no big deal.

[bobbyburns]

I'm sure that's a Kay, and I'll bet he is right about it being celluloid. I've superglued, and epoxied cracks back together before. Either is a temporary fix (a few months-ten years?), and more work than making a new one.

[bernabe]

If youre filling gaps between bindings, what Chris said. If your filling a gap between the binding and the side wood, perhaps a different material that would be a close substitute for the wood sides would be a better idea for filling that space-i.e. wood is missing not celluloid in that gap

[Loudloar]

How about getting some clear pick guard material from Stew-Mac and adhering that over the top, then cut to shape and reglue to the guitar? That would preserve the "funkyness" but give you a durable layer on top.

Steve

[Plinky]

Wow - lots of great feedback (oops - sorry - primarily a guitar issue :)) )

1st off, it is a KAY guitar - part of my preservation motivation is that there is an ever so faint KAY logo on the pick guard. Easy to miss - it looked like the attached pic. -- As for styrene - hmmm.... is that like what old models (cars, etc) were made from? Polystyrene maybe? This does seem very different than that sort of thing - it's almost like amber (the tree sap stuff) - crushing it to bits did cross my mind, but keeping it somewhat intact by softening and epoxy seemed like a better idea.

The idea of binding it to a clear plastic is a good one that did cross me mind - however, my biggest problem is its warp-age. If it was already flat, no worries really, I'd try clear plastic and / or clear epoxy. I don't want it to be too thick over all, hence my considering the epoxy to both bind and coat. However, if I can't flatten it by softening it first, a good crushing or a full replacement is my best 2nd direction.

I did write a chemist about this, no answer yet. But I do understand that celluloid dries out as a result of the evaporation of one or two of its basic chemicals. I kinda figured that if something evaporating would warp and crack it, then something added back just might soften it to be salvaged; then I'd rework the logo via a little engraving and white enamel paint, before a final clear coat or something.

If all else fails, it would be a worthwhile experiment to try acetone in small, diluted amounts - something to ponder... if all else fails ~o)

[Herb H]

Don't know what you'd dilute acetone with. But if you do decide to try solvent, a lacquer retarder would probably be a better solvent than acetone. The acetone is very thin and volatile, dries without giving you time to do much of anything. The lacquer retarder will evaporate much more slowly, is more of a candidate for bonding cracked pieces back together. One common principal ingredient in lacquer retarders is butyl cellosolve and another is butyl cellosolve acetate. ONLY lacquer retarder or retarder/thinner for nitrocellulose lacquer (not acrylic lacquer) -- not any kind of polyurethane retarder or paint retarder.

[Plinky]

Ahh Herb ~ this sounds like the ticket :)

My "dilute acetone" thought was exactly thunk for the hope of slowing down / controlling its effects (I'd have tried alcohol or something). Lacquer retarder sounds about right. I wanna create a "mold" out of aluminum that is the right shape for the pick guard, put it in and let it soak - watching its progress while deeply inhaling the fumes (hmmm maybe that's not right... :disbelief:) -- Once it softens then hopefully it can be drained and allowed to harden in a more intact state, then coated in clear epoxy.

This works amazingly well in my imagination :))

Now you got me excited Herb ~ I'll keep ya posted ~:>