Silicon Carbide vs Aluminum Oxide
Silicon Carbide (SiC):
– more expensive
– harder (9.5 on Mohs hardness scale)
– does not dull with use – fractures and creates sharp but finer (but still effective) grit
– creates light at impact spot (triboluminescence)
– not ideal for blasting surfaces to be clear capped (creates “fogging”). Jury is out on cause – some think it is devit and others suspect that the deep pits caused by aggressive blasting might trap air, causing small bubbles. Not an issue on uncapped glass.
Aluminum Oxide (AI0 )
– more likely to be available locally
– 9.0 on Mohs
– Dulls with use (doesn’t last as long as SiC)
– creates static electricity when blasted – dust sticks to glass, cabinet, etc
I use SiC (I do a lot of material removal in my work) – but there are days I wish I used AI0I’m sure if I used AI0 there would be a lot of days that I wished I had SiC.
Unless you plan on a lot of aggressive (deep) carving then you are probably better off with AI0
Most importantly – NEVER use plain old sand. Blasting with sand releases “free silica” dust into the air — which is the same nasty stuff that gives coal miners silicosis (aka black lung disease).
Helios Kiln Glass Studio