Sandbags

For smaller or uneven stones a sandbag will stabilize the art-to-be. You can cut the legs off an old pair of jeans, fill it 2/3rds with play sand, and seal the ends with plastic ties. I like using old truck tire tubes from my car repair place (sometimes a little hard to get, but free). I then cut them in half or thirds and similarly secure them with ties after filling them partially with sand. This way if I hit the rubber “bag” with my grinder it just bounces off rather than cutting it open.