Using Unknown Paint For Stain Glass Painting

by frank
(Sacramento, CA)

I was given a number of small jars of paint. It came from the estate of a ceramic and pottery teacher. Some of it is in powder form others are liquids. It is over 10 years old. Can I use this for coloring in some of my stained glass works. How could I test it?

Milly's reply:
I've got lots of similar pots of unknown glass paint! If they are ceramic colours they're probably onglazes - they will work on glass but in my experience are opaque and a bit 'dead'.
To test them for stain glass painting, you need to mix them with a bit of water and fire them - all these glass painting instructions are in the 'Painting' section of my site - and evaluate the results.
Do think about whether it's worth it for you - you'll have to test everything and if you like it, you probably won't be able to purchase any more. It may be better to start from scratch with some dedicated stain glass paint, with manufacturers instructions. Good luck.