Glass Tumble

What is meant by fake glass? Is it because the blue got tumbled out or is it actually not real glass? I've never tumbled glass before so those are interesting.

CLErocks yes glass builds up pressure inside the barrel. The only time I’ve had tumblers pop open was with glass or obsidian. I think the tiny bubbles inside the glass are pressurized.

Your glass turned out nice.

Hi dug

Glass and obsidian aren’t crystalline like most rocks or minerals. They are considered a viscous fluid. When they are formed, microscopic bubbles are incorporated in the material. In older glass you can sometimes see the bubbles.

I think these bubbles are under slightly more than atmospheric pressure. As the glass is ground down and the bubbles are exposed, they release their tiny amount of pressure. It doesn’t take much of a pressure buildup to pop the top off a typical rotary tumbler which mostly rely on a friction seal. A tumbler with a solid mechanical seal probably would not build enough pressure to fail.

Anyway, that’s my theory and I’m sticking with it. jamesp could probably add more info. He has tumbled more glass than anyone I know.

Welcome to RTH by the way. It’s a fun group of people.

Man! Does it ever!!! Hahaha Lesson learned fast!