ok guys I have 2 - 800 pound blocks of lead I need to make a bigger smelting pot my idea is to get a piece of pipe bout 20 or 22 inches round and weld a thick piece of plate steel on the bottom how long a piece of pipe would I need of 20 or 22 round for the 800 pound block of lead to melt into and still have bout 4 inchs of extra pipe for room to flux and stir thanks