I used the stainless steel ring on the left to sandcast a copy in sterling silver. You can see how rouch and textured the band is from the sand.
From there I use files and abrasive wheels on my dremel to smooth the surface.
I love playing with different objects in the sandcasting. Just to see what patterns do well or don't do well. I've cast acorns, rings, twigs, and ingots using this process.
I got my sandcasting kit from Craig Dabler on Etsy. Great casting tools and patterns for sale in his shop. He also has a great group that will help you learn how to use the casting equipment to create fun items.
You can learn all about it here. https://www.facebook.com/diycastings/