old celluloid PG heat bend

[Ry Charters]

Howdy, I've got a '51 Epiphone in for some restoration. The pickguard was severely warped and I planned on making a new one. But out of curiosity, I decided to try and bend it into shape by wetting my granite block and heating it under a wet maple veneer with an iron. It got fairly hot and I clamped it to cool for around a couple of hours. It looks very good now, but I'm wondering how much memory the celluloid will have. Will it curl back up in a month?
Thanks,
Ry
www.chartersguitars.com

[Ry Charters]

Actually, its three hours later, and I still have it clamped up as it is still a little soft.

[Ry Charters]

Also, its about 1/8" thick.

[Russell Vance]

Celluloid is a "thermosetting plastic" which basically means that it will assume any shape it is moulded into under sufficient heat application. Once set it sort of stays that way unless it is heated again (such as in a hot car in a black guitar case etc - you know the story). If it is celluloid it will stay put. R.

[Tom Krebs]

You may be aware of this already? Beware of that thing off-gassing and corroding other parts of the guitar. Is it stable, or kinda greasy and smudged on the surface?

[Ry Charters]

Thanks Russ, that good to know.
It was a little greasy and very bubbled, but I cleaned it off and have it rebound and am sanding it flat again. I'm not sure what you mean by "off gassing". I know it will continue to dry and thus release some of its vapor... does this happen more so with an older piece than with a new one?

[Tom Krebs]

Some of those older pickguards are completely toxic. As far as I know; this cannot be repaired. The old guard must be replaced - and moved far away from the guitar. The plastic will never 'dry'. The gas will continue to corrode metal and other plastics around it. See my link below with some shots of a 1970's Gibson Super 400 that suffered this problem. I removed the grunge, replaced the old guard, and left the case open to air out for a week. I have seen a many guitars with this problem. Not sure what the dating would be as to when 'they' got this solved. It's sad, but true.



http://www.monsterguitar.net/gibson_super.htm

[Ry Charters]

I don't know... there was plenty of chrome near this one and it looked fine. I guess this guitar spend the past 5 years in a case as well. I don't doubt at all that the images you put up were from the pickguard. But it seems to be hit or miss, right? Like how some old tuner knobs are almost falling off, but others from the same model/year are fine. I don't understand.

[Tom Krebs]

Bingo! Just hoping you were aware that this is a possible problem. Cheers Tom

[Rob Mercure]

As noted there were lots of materials referred to as "celluloid:" nitrocellulose, cellulose acetate, NC with camphor (my favorite - and homeland security's). Some of these when heated with steam will become cloudy - premanently as best I can tell (of as permanent as I'm likely to be) - and unattractive. As with most things experimenting with a small corner is probably a good idea first.

Rob