Thread: Price reduction
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Old 02-17-2020, 12:47 PM
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David Patchen David Patchen is offline
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Guys - here's notes from a conversation I just had with our tech about how we melt Bomma. Note that we have a 600# Stadelman electric furnace that we run at a working temp of 2150. He's usually doing a large charge once a week and a mid-week small charge. He doesn't wash the Bomma but he does give it a quick inspection and tosses out nuggets that look stoney or have impurities, then tosses it in. Here's what he does:


If 100 or less: we leave the furnace at 2150, toss in a bag (55lbs) distributing the nuggets across the surface of the glass. Waits for the new nuggets to completely melt in until the surface is flat (takes ~20 min), then squirts water at any large bubbles to pop them, wait another 10 min, then tosses in a second bag. Lets it all sit for for 2 hours then squeezes to 2000, then and back up to working temp.

If 400 lbs: We bring the furnace up to 2250. Tosses in a bag (55lbs) distributing the nuggets across the surface of the glass. Waits for the new nuggets to completely melt in until the surface is flat (takes ~20 min), then squirts water at any large bubbles to pop them, wait another 10 min, then tosses in another bag. Continues with this process about every 30 min or so until the charge is complete. (Note that in a 600lb furnace there's a lot of thermal mass, so other furnaces may take a great deal longer for everything to flatten and melt smooth). After the last bag wait 30 min, then a program brings the furnace down to 2150 (our working temp) over about an hour. Furnace holds at 2150 for 2-3 hours. Then squeeze.

The Squeeze: For both melt cycles we squeeze by dropping the furnace to 2000 degrees over 1:45, let the glass sit for 2 hours at 2000, then take 1:30 to return to working temperature (2150) over 1:30.

Hope this helps.
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