To remove the shelf primer, simply soak the pieces in vinegar. After 20 -30 minutes, shake the container gently and remove the cabochons. Any remaining shelf primer should now rinse away easily. If there is still shelf primer stuck to your glass repeat the process with a longer soak.
If you do not have access to a sandblaster, you can remove light devitrification with glass etching cream. “Armor Etch” is one brand that is widely available in the United States.
Paint the cabochons with a coating of cream and wait 30 minutes. For heavier devitrification, a longer wait or additional treatments may be required.
When etching is complete, rinse and clean the cabochons. The surface will no longer be glossy, but the “scummy” devitrification should be gone.
Return the sandblasted (or acid etched) cabochons to the kiln for a final fire polish. Use only shelf primer on the kiln shelf – shelf paper (like Bullseye’s “Thin Fire”) can cause slight hazing when fire polishing glass.
Here’s the firing schedule:
|1||500° F / hr||1000° F||none|
|3||FULL||950° F||30 minutes|
|4||300° F / hr||725° F||none|
Once the firing is complete and the kiln has cooled, remove your finished cabochons!
Now on to the wrap up…
Back to Fused Glass “Puddles” Start