The Talking Machine Forum — For All Antique Phonographs & Recordings

Fifty or so blue amberols have come up for sale near me. Cheap. But most are missing a large part of the plaster of paris. Do people patch these successfully? What is the material of choice? It seems a tube of silicone/plaster of paris might be easier to work with than mixing it in a pail. Then wax paper around a mandrel to mould the shape?

mjbarnes wrote: Tue Feb 25, 2025 12:26 pm Fifty or so blue amberols have come up for sale near me. Cheap. But most are missing a large part of the plaster of paris. Do people patch these successfully? What is the material of choice? It seems a tube of silicone/plaster of paris might be easier to work with than mixing it in a pail. Then wax paper around a mandrel to mould the shape?

I know people have tried replacing the plaster, but I'm not sure how successful they were at it. For one thing, the outer covering is a very tight fit with the plaster. So, when the plaster is gone, the outer skin sinks into the void, making a low spot that can't be corrected. In other words, the cylinder will no longer be round. Replacing the plaster, with whatever formula you choose, will not make it round again.

one time i had a very badly warped one ( got it free from a flea market) and thought that if i used a torch lighter and mildly warmed it up, i could mold it back into shape. it was going well until it wasn't. long story short there is a small hole within the warped section, but the end that wasn't warped plays very well

If I'm not mistaken, celluloid is highly flammable. Leaving aside the undesired results of this experiment, probably best not to expose it to open flame.

phonograph guy3435 wrote: Sun Mar 02, 2025 7:12 pm one time i had a very badly warped one ( got it free from a flea market) and thought that if i used a torch lighter and mildly warmed it up, i could mold it back into shape. it was going well until it wasn't. long story short there is a small hole within the warped section, but the end that wasn't warped plays very well

My immediate reaction:
GAAAAAHH

There used to be a saying: to 'go up like a celluloid collar'. Just be glad the FD didn't have to show up.

- Bill

drh wrote: Sun Mar 02, 2025 7:55 pm If I'm not mistaken, celluloid is highly flammable. Leaving aside the undesired results of this experiment, probably best not to expose it to open flame.

welp, now i know

I tested this by removing the celluloid from two cracked BA's which had split the entire length of the grooves. Put the two celluloid sleeves inside each other, lit a match, and got a six-foot fireball that refused to go out until the whole thing was a tiny palmful of ashes.

You about had a very very bad day!

yeah i waved it around right after it started up so the flame kinda shot out of the end for a few seconds and it just made a lot of smoke.

And the smoke is very poisonous...

finally, it contains an oxidizing agent which means you could throw it in water and it still wouldn't go out.