Im told that the Al from pistons is nice to work, melts nicely for casting into ingots and machines cleanly. Another reason to visit Looms?
Havent used pistons myself but I have used hard disc chassis; nice light alloy that melts easily (dont know temps - got no thermocouple).
Used the melt to cast a replacement key cos the buggers* wanted £8.50 for what seems to be a bog-standard mortice key.
Theres someone with a website about casting etc who uses HDD Al regularly with good results, I'll try and dig out his URL.

Does anyone in the Derby/Notts area know a good source of fire bricks?
I only need a dozen or less for a small electric Al melting project, I dont need a pallet full! Preferably the ones you can cut with a wood saw.

Jim

*I tried 3 different keycutters, one had a nice engraver that looked PC driven. He wouldnt let me play after Id sniffed at his prices.:heehee: