I've decided to make several aluminum balls using lost-foam casting. Instead of the foam balls I took 3 ping pong balls. I wasn't sure if it would work right but finally it did.
Step 1: Putting Ping Pong Balls Inside a Saucepan
My flask was to small for this pattern, so I've decided to use a saucepan.
Step 2: Casting
When aluminum was melted I started to pour it but very slowly. These balls are very flammable.
Step 3: Nice Texture
In result, I see that these balls burning very different to the foam. The surface is not smooth but looks very good. They have a lot of micro-carving.