Thread: How do I fix these scales?

Post #8 in this thread http://straightrazorpalace.com/works...les-fixed.html shows a set of scales repaired with acetone. The scales are still holding together.

Charlie

Originally Posted by Pete_S

Model cement might "weld" the celluloid, model cements melt plastic then allow it to dry and reform. It might not be that strong, though, or might not even work on that type of plastic.

Tried it, I had no luck it just peeled right off... Testors is what I had

I had to post again, I was thinking about my previous post, I did not get the point across that I wanted to make.

Celluloid is a glue. How it appears to us depends on the amount of solvent that is mixed in. With very little solvent it appears as a hard plastic. With a little more solvent it turns into a glue-like Duco or the old school solvent based model airplane glues. With even more solvent it turns into what we call lacquer-like Deft. It is all basically the same resin - it just depends on how much it has been reduced with solvents.


Charlie

That's really quite fascinating! That explains why I was reading in that old Popular Mechanics that the best glue for celluloid was more celluloid dissolved in acetone. (Does the solid form of celluloid just contain less of that same acetone, I wonder?) Now if I only had some scrap celluloid, maybe I could get somewhere....

Check out the msds (material safety data sheet) for Duco cement.

Duco Cement, 14445, MSDS
check out section 3

It contains cellulose nitrate and camphor (cellulose nitrate and camphor are the main ingredients of celluloid), acetone plus some other solvents. This would be a good glue to try.

The celluloid that your scales are made of were formed with heat and pressure. There is probably just a small trace amount of solvents left in the celluloid.

Charlie