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Old 03-21-2004, 12:32 PM
David Williams
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[quote]Originally posted by Durk Valkema
[b]Many studies have shown that the most effective transfer of heat both radiation and convection is direct convection/glass, radiation/glass.
So electric elements should see the glass for best results.

That is a pretty major flaw in most of the electric furnaces with the exception of Denver. The surface of the glass is always the coldest and you're heating through the pot which is inefficient. I use the "thermal flywheel" ring too and I think its aa good a design as you can have with wire because it keeps down the chance of cullet popping on to the elements. I have about 1/2" between the pot and the ring. I have Steves elements too and they've been going for about three months with no failure yet. I've been melting cullet and last time I started up I decided to just run it at 2150 24/7. On the theory that running a bit high all the time is better than juymping all over the place. I do have trouble fining out my cullet though.

ps. one amp per pound of glass? Thats nuts! I have my scr dialed down to 34 amps and thats fine for me, charging recovery @ 2150 is around 20 minutes for 25 pounds of cullet. In a 100lb pot.

pss. I mean its nuts for it to be a rule of thumb. Melting two pounds with two amps is just as absurd as melting two hundred pounds with two hundred amps. But between say, 30 to 60 pounds it might make more sense. But a 60 pound furnace running on 60 amps is still pretty overpowered.
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