Meniscus Mirror: Making a Grinding Tool, Attempt 1
To grind my 12" blank into a mirror, I need a grinding tool. Since the glass is already curved, I’m going to make a grinding tool for my slumped telescope blank using these ceramic tiles I bought and dental stone, a waterproof plaster! The tiles are hard and will resist the grinding from grit pieces; they’re placed onto the curved glass so the tool takes its curved shape, and dental stone will be poured over this and harden into a convex tool for grinding with hard ceramic pieces sticking out. Ideally I want a 1" or thicker tool.
I added the water first, then slowly added more dental stone and kept mixing. That was a good idea compared to adding water second. However, dental stone hardens incredibly fast. There was a moment in the pouring before all of the powedered dental stone was added when I noted it was getting a bit thick… and I decided to keep adding more, and the mixture stopped being liquid and smooth. That was my downfall, and it happened only after around minute 12. Sigh.
Result: Failure. Most of my dental stone hardened into a giant block in the bottom of my bucket that I couldn’t get out. So much for having a 1" thick tool.