The late Dave Gingery wrote a book on making a small electric furnace for melting aluminum and bronze. It may be the sort of thing you're looking for:http://www.lindsaybks.com/dgjp/djgbk/found/index.htmlThe furnace is roughly 6-8" i.d. and 6-12" inside height. Dave used castable refractory to mold the furnace, but insulating softbrick is probably more durable. Kanthal elements will reach higher temperatures than nichrome. Softbrick and kanthal are available on eBay and elsewhere.