Thread: Refinishing Plastic Scales?

I have never actually figured out what it was, I have always just sanded them polished them and left them alone but I never ran into a "flimsy" problem either... The problem with Epoxy or Poly is that hardly anything sticks to the celluliod... I am at a loss as to what to use ?????

WOW. If you are at a loss, then I am willing to chock it up as one of the great mysteries of the universe.

Originally Posted by gssixgun

I have never actually figured out what it was, I have always just sanded them polished them and left them alone but I never ran into a "flimsy" problem either... The problem with Epoxy or Poly is that hardly anything sticks to the celluliod... I am at a loss as to what to use ?????

I make glass plate negatives from collodion flowed onto glass. They need to be protected from the atmosphere, and the most popular varnish is gum sandarac (65g) dissolved in 190 proof alchohol (470ml - "everclear") with lavender oil (50ml). Other varnishes that stick use gum dammar and benzoin.

Collodion is the main constituent of celluloid, so I suppose that it is the high alcohol content that helps it bind - the oil is just to let the varnish flex a bit. Smells wonderful.

Whether it would stick that well to celluloid I don't know - I just usually buff the stuff under slow speed with tripoli. Only one set so far (fingers crossed) has ignited. Quite spectacular - a job to put it out once it takes fire. At least it doesn't explode like the very early celluloid did.

Regards,
Neil

Originally Posted by Neil Miller

Quite spectacular - a job to put it out once it takes fire. At least it doesn't explode like the very early celluloid did.

Sounds Safe!

Originally Posted by DPflaumer

Sounds Safe!

Not as much fun as making the stuff in the first place - dissolving the cotton in a mixture of hydrochloric and sulphuric acid is prone to disaster (I did it indoors once and the whole room filled with corrosive orange clouds of gas - wife wasn't amused) or even drying the resulting guncotton after washing it - it can be temperamental and explode for no good reason..It must have been worse back in the 1850s-60s when they had no quality control or marigold gloves...

Neil
Do you think possibly that the coating that he took off was a residue from a Acetone type wipe way back when... I was always thinking that they wiped them with something like an acetone to get a smooth high gloss finish...

It could be something like that Glen - there is a shrinkage effect that produces a rippling surface sometimes - they used to call it "crepey lines" - wiping the surface with a solvent would act like a liquid sandpaper, probably. The other possibility is that there was some sort of "edge-effect" where the celluloid was against the sides of the mould, it could also have been deliberate, like the gel-coat they paint/spray against fibreglass moulds before the resin goes in.

I considered that it was the celluloid itself, just weathered on the surface or harder there, due to the casting process itself. I really think that it was a protective coating however. The Boker especially had relatively thick clear, glossy coating that made it more rigid and I'm guessing more stain resistant. Today I went to the hardware store and got a couple I thought I might try. One is an acetone based spray finish and the other is an epoxy.

You think the perceived flimsiness could just be the amount of material you have taken off plus the fact that they aren't mounted to anything solid at the moment?

I can't really help you, anything plastic or cellulid that I've yanked I've always replaced with wood.

Actually the clear finish was about all I took off, other than some light scratches near the ends, so I don't think it was from lost material. The Bismark may have not had much but the Boker for sure had a rigid coating.
I went ahead and poured a layer of epoxy, and am thinking that might be the closest thing to the mysterious coating I am trying to restore. Of course it is still curing, but so far it looks pretty much what I'm going for. Plus the added durability is a bonus. I will add some pics once it hardens.

Originally Posted by Visibility

You think the perceived flimsiness could just be the amount of material you have taken off plus the fact that they aren't mounted to anything solid at the moment?

I can't really help you, anything plastic or cellulid that I've yanked I've always replaced with wood.