Home forging

[magicniner]

You can cast parts that can't reasonably be machined, that's a great reason to melt aluminium and other metals, I have a propane fired furnace rated for 2gk of Iron, although it sees more lead/antimony than iron or aluminium.
If it's for parts you are machining you may be better with bought stock where that works for form of the parts, you will not match the tensile strength of commercially manufactured bar or plate stock with home cast and without testing facilities you will not know the exact composition of what you're throwing in the pot or pouring out of it.
You should only need a blower for mains natural gas, none of the burners on Ron Reill's site required blowers and some of the guys involved in propane burner development got furnaces running at temperatures where UV protection for users became necessary.
The main thing is to enjoy and learn but don't expect to end up spending less ;-)