Figuring

This is the stage that I am in right now, so this is definitely a work in progress. Figuring so far has resulted in a massive turned down edge that I couldn't even measure properly on the Foucault test.

Part of the problem was an old lap that had very thin edges, old hard pitch, and a sudden change in the weather. Old Al Ninyo gave Pennsylvania a warmer than usual winter, but the temperatures were also more erratic. Sometimes I didn't need heat in my garage, and sometimes a 25 swing in the temperature made the garage take most of the evening to warm up. So I put my mirror away until spring gives us a little more consistent temperatures.

Figuring a mirror is truly an acquired talent. In leiu of a detailed account of my success story, since it isn't a success story yet, I'll give a list of the mistakes that I have made so far. This is NOT to discourage anyone, its just that hopefully some of you may not have to repeat the mistakes I have made. Go make your own mistakes.

1. Don't try to figure on the same lap you did your polishing on. Re-melt and soften your pitch if need be. I put a major dog biscuit in my mirror this way.

2. Do tool on top most of the time. I made my awful turned down edge by polishing exclusively mirror on top. Just before putting my mirror away for the winter, I pretty much eliminated the turned down edge by using a slightly undersize lap with short, tool on top strokes.

3. Don't Foucault test until you are done with the polishing.

4. Patience, Patience, Patience.

There will be more on this page as I progress with figuring. I hope to be able to include a few photographs of the mirror under test.

 
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© 1997 Michael Coslo