I finally got around to testing my furnace after months of the deep freeze here. It was quite a disaster, but not completely unsuccessful. I am new to this and it was my first burn ever. I decided to started with just beer cans to see how it worked (to save my good aluminum for later). So, I think the problems I had were due to two major factors. First of all, it is hard to find good charcoal here in the off-grilling season. The only place close to me that had it was a very thin light weight wood charcoal. 20170311_142647.jpg. The second problem was that I was using my shop vac with the hose attached to the outlet as an air blower. I think that it was way too strong. I basically ended up with a crucible full of charcoal, and the charcoal was burning extremely fast. I had to replace it 3 times. Today I built a new blower from an old stove hood 20170311_141705.jpg(haven't tested it yet as I need to get better charcoal and I burnt out my crucible (a small cooking pot) on the first try). So my question is, how strong should the force of air be? The shop vac seemed way to strong, the stove hood seems like it might be a little weak. Also, I am wondering about the placement and length of the tuyere. How easily or hard could it be adapted to change to a propane burner? Also does it stick out too much in the inside?20170311_141602.jpg(also notice that I use sheet metal rolled up the form the inside chamber, when I was ramming the calcium alum cement the sheet metal wasnt strong enough and formed a misshapened form. And the last question. I noticed that there was some deterioration of the hot face close to the tuyere, is this normal?? 20170311_141622.jpg. And, as I said earlier, it was not completely unsuccessful. I managed to get one ingot out of the burn (if you can call it that, it didnt quite fit the only thing I had handy for a mold at the time) 20170311_224810.jpg. That was about 10 beer cans.