Un-warping a 78?

[estott]

Some discs will go limp with a soaking in very hot water- Little Wonder and the American Pathé sapphire ball discs will do this. Never try it with a cracked disc, the crack will open up.

[HisMastersVoice]

You should be able to achieve more even and controllable heat by using your kitchen oven rather than a hair dryer which could scorch the surface.

I've used this method as well, with great success. It must be the lowest setting, and you have to constantly monitor it. The whole process may only take a fraction of a minute. In my new oven (well, new to me, it's from 1942), the large pilot light keeps the oven warm constantly, making it perfect to whip up a batch of freshly baked 78s without even turning it on.

[premis2]

does one place the plate glass itself in the oven and lay the record on top or do you make a sandwich of two pieces of plate glass ?

[HisMastersVoice]

does one place the plate glass itself in the oven and lay the record on top or do you make a sandwich of two pieces of plate glass ?

Personally, I wouldn't put one on top. The record will flatten on its own, no need to put unnecessary pressure on it.

[schallplatte]

does one place the plate glass itself in the oven and lay the record on top or do you make a sandwich of two pieces of plate glass ?

Personally, I wouldn't put one on top. The record will flatten on its own, no need to put unnecessary pressure on it.

Either way will work, and I agree with the above that it's not required to place the record between 2 pieces of plate glass to achieve a good result. If the record is very badly warped, heavy plate glass might place too much stress on the record, so caution is indicated. Nonetheless, I've achieved very good results with the record sandwiched between 2 pieces of plate glass. I then placed the glass sandwich in a cold kitchen oven and gently heated at a very low setting. Through some experimentation I was able to estimate optimal time and temperature to correct warp, with least possible heat exposure. The process is quick and only a low temperature is required. Remove the record from the heat source and allow to cool rapidly to minimize deleterious effects of heating. In the process, less is more.

[Curt A]

Plate glass is the correct item to use, but only heat the record for a short time. In the sun, no more than 20 minutes will do it. Then let it cool gradually...