making ali ingots

[grimme]

if you use angle iron moulds for ali ingots must you preheat them? or does it depend on how thick the metal is?  ive seen a video of ali exploding in a cold mould but cold  baking trays are ok? i usually just try it but dont feel inclined to be adventerous with moulten metal

[Glenn]

Youtube would not be a first choice for information on this subject. 

 

If you do not know what you are doing around hot liquid metals, STOP and do a lot of research into the subject. This includes making contact with someone who knows what they are doing and does it in a safe manner. 

 

Things can and do go wrong fast, so always wear personal protective gear, and have a plan B, and a backup plan for the plan B.

[Nobody Special]

Everything Glenn said, extra emphasis on finding a friend with a LOT of experience. Splashing metal from a mold or failed crucible HURTS. (Not that I'd know..........the scars have mostly faded, right?)

 

That said, used to have good luck with casting ingots in green sand. In an absolute fix, wet play sand works too, to a point, but you end up with more particulate matter in the outside, and the outer surface is much rougher/more porous. You still want to find someone that's done this with green sand, (or play sand) so you learn to do this right, without getting flash burns from steam, metal spattering, etc.

 

You can also (if you have a large enough container with water, preferably metal) pour it in slowly, with all ppe maxed out to make shot or streamers, but they're not regularly shaped. See above cautions. If your casting experience is limited, absolutely do not try without someone who's done it.

 

I really wouldn't try some of the baking tray/muffin tin gimmicks I've seen. There's a number of problems with them, and even if it works, it can be next to impossible to free them from the mold after without wrecking it.

 

Casting is like learning to play clarinet, any idiot with a plan can melt metal, but it takes years of practice and mentorship to become really good at it.