How to choose sand casting?

You can really do any size, any metal, and any level of detail. It all depends on the type of sand you choose, the type of casting you’ve picked, and the heat you use. For smaller things, such as bakeware, dumbell,  I would tell you to use a Lost-Material casting, which is to use a material that will vaporize to the heat, which allows you to keep lots of detail. And for larger casting, such as disc brake, municipal cover, I would advise to use a higher heat, and preheat your sand too. I’m a gunsmith, I use casting to make parts. That means I could be working with something bigger that I can do in an open-top sand casting, or it could mean I’m working with things so small that it’s best to over size the part then shrink it with files.

Regardless, the level of detail one can do with casting depends on their skill with casting.