I have plenty of cast auto partsIf you are looking for scrap aluminum to use for casting, try to find items that were originally made as castings. I know it sounds overly simplistic. Stay away from cans,plate,and extrusions. Look for things like transmission cases and engine heads.
Pistons are the worst, they contain iron, used for prevention of sticking to steel molds, the iron narrows the solidification temperature range, so molds need to be poured extra hot to avoid short fills, and results in shrinkage defects. Scrap that has been sand cast is best for remelting and casting.
IDK. Thats why I will go with a known alloy when I get around to tryingLooks kinda like permanent mold stuff, maybe not the best choice.
Why is the glossy finishes on parts that are not machined.IDK. Thats why I will go with a known alloy when I get around to trying