I found this great website that has a wonderful FAQ all about homemade Cold Porcelain.
Here is the full page with tons of great info:
Here is what it said about storage:
- Keep the porcelain clay in good condition by storing it always in a zip plastic bag and inside an air tight container. This will maintain the consistence of the clay and it will not dry.
Here is another page with great CP information:
This page also has great information:
- "Store cold porcelain paste in an airtight bag or tightly wrapped in plastic. Sometimes I do both…wrap in plastic first and then in an airtight bag!
- Try using a product that sucks air out of plastic bags. Ziploc makes an inexpensive one.
- There’s some new, latching plastic storage bins on the market. They are inexpensive, small and are suppose to be airtight. By Sterlite, the type with a rubber gasket to help seal. I bought some but haven’t put them to a test yet!
- Do not store clay in a dark drawer for a long period of time, this could make the paste moldy.
- Store CP paste in a dry area at room temperature. Do not refrigerate, but you can freeze.
- Paste that has been tinted with color will dry out faster than non-colored paste.
- Don’t store different colored paste in the same container if they could touch each other and transfer color.”
Here are a few more recipes from the same place:
Hope these help you!