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Old 11-04-2003, 01:42 PM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,269
Pete VanderLaan is on a distinguished road
The first formula does have a ton of silica and it is durable and the silica content is why the glass works well in a torch. It was a glass I used that I cut and polished a lot and it polishes beautifully. That is because of the potash.

The second formula is a glass designed to fit SP87 hand in glove. I use it for my red and opal silver amber formulations when matching SP87. It also makes a very nice turquoise blue I am currently working. SP87 color base makes OK reds but the ambers are dirty from all the spars that Tom has in there, so this stuff is spar free, which is key to color glasses.

The third formula is simply wrong.

Interestingly in our drought, I have increased the amount of Soda ash in that glass from 20.25 to 20.75 to keep it in line with the Spruce Pine.

I would melt hotter than 2000F unless you rigourously follow the Corning Protocol of turning it up after the melt reaction is complete. Using 325 mesh sand is a two edged sword. It melts easier but it also clumps easier. It can get very problematic when the humidity goes up and in a cold melt, it can create silica stones. At the same time I say that, if the dusting bothers you, you can spray the batch with a nozzle from your local greenhouse that gives a fine mist. It will knock down the dusting. Mist to taste. It's kind of messy.
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