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Old 03-03-2017, 12:52 PM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
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Join Date: Apr 2002
Location: Chocorua New Hampshire
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I don't think 30 grams in 7 lbs to be overkill. You could try 25. Chromes are really difficult to melt though and the dichromate really needs to be crushed before you try to add it. Adding to cullet is the hardest way to go and candidly 2100F is way too cold for that. What you see as black flecks are corundum stones and are the result of a cold melt with coarse dichromate. It's quite easy to crush in a mortar and pestle. When I teach that junk, I encourage students to give the dichromate a bath in lithium carb when crushing , but that's in a batch glass, not a cullet. Lithium is a powerful flux and it's not hard to throw the expansion all to hell. In that light, much as I hate the stuff, you could do the same thing in a bit of borax since it won't mess with the expansion much. The 20 mule team stuff at the grocery store will do.
Good Luck.
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