/diy/ - Do It Yourself

I need to make a plastic wheel roughly 14 inches in diameter and 7 inches thick. Never custom made a plastic mold before. Does anyone know how I can do this? I have a ton of plastic available around for the molding. But I'm not sure what I can use as the mold itself.

>pic unrelated, I have no image relateable to topic

I've been melting down scrap metal for a while now and have about a ton of 1 and 5 pound bars that I'd like to start selling.

I've been asked a question by a local complex that may want to buy the metal. But he needs to know exactly what kind of metal it is. For the most part, my scrap is aluminum. But I know there are several batches that ended up with tin, copper, and other alloy sources.

How do I check the bars and know exactly whats in it?