So I'm pretty new to the casting world so forgive me if this has already been covered. I bought my first melting pot, a Lee production pot IV, and finally got to try it out the other day. Turned on 10 I was impressed how quickly it melted down 8lbs of wheel weight ingots sweetened with 2% tin, I reduced the setting to 5 figuring that would be a good starting point. Using a 2 cavity Lyman 429421 mold I was getting good bullets after just a few warm up pours. Soon the bullets were beginning to get frosted so I set the mold down to cool for a min. It was now that I noticed some yellowish orange crust on the lead. Thinking nothing of it I fluxed with sawdust, skimmed, added a few more ingots and a layer of sawdust to protect the surface of the lead. I resumed casting but began getting frosted bullets again after just a few pours so I reduced the setting to 2. Didn't seem to help with the frosting much and the sprues were taking longer and longer to solidify. Then I noticed the yellow orange crust was back in spite of my protective sawdust coating. Skimmed again, few ingots, and more sawdust and was back to casting. After about 10 mins I noticed the strange crust returning and mold getting to hot again so I decided to call it a day. Skimmed the crud, and shut the pot down leaving it half full. I decided to do some research and from what I can tell, the strange dross was dreaded lead oxide caused by overheating the alloy. I was then curious to test my equipment. I removed the "thermostat" assembly and tested the resistance through it with a multi tester, there was no change regardless of knob position. I then reattached the wires and carefully tested voltage going to the coil while the pot was ruining. Again no change in voltage regardless of the setting. After reassembling the pot I plugged it in and turned it down as far as it can go and it melted the half pot of alloy in about 8 minutes. What y'all think? I'm no electrician but it sounds to me like the knob is stuck wide open. Anybody have a similar experience?
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