Now that we have constant air in the fab shop we can now use the sand blaster full-time. I can happily report it can strip an intake manifold clean in half an hour. :)
It does however need a vacuum or something to draft air through it or silica dust comes out the vents and you really don't want to be breathing that in. I bought a very nice industrial ShopVac for $20...and it promptly suicided the motor bearings (a new motor is $150 which doesn't sound too bad when a replacement vacuum in that style is $700) but we can still use it with the other ShopVac as an intermediate bin to recover medium as it gets sucked in.