Sanding and Polishing Thundereggs

Two basic lapidary machines can be used to sand and polish thunderegg halves quickly. Both involve sanding the pieces dry.

- BOB RUSH

Safety First: Because these machines create a lot of silica dust, suitable respiratory protection must be worn. Different types of respirators are available, and you must follow the instructions for each type to determine the level of protection you require.

One machine is the Richardson’s Ranch high-speed sander. It is an inverted sanding disk utilizing a seveninch diameter wheel with silicon carbide sanding disks. When using this sander, you hold the stone up on to the rapidly spinning disk and move it about to sand off the saw cutting marks and any scratches present. I don’t often use this machine because my arms tire from holding the rock against the wheel, which also tends to leave circular sanding marks on the thunderegg.