The other option (I’m pretty sure you won’t like this one) is to rent a 185cfm compressor and get the blasting done 10x faster.
Another vote for this.
Bunch of random sandblasting thoughts......this is from a commerical context so filter as required.
It takes a lot of air, that is for sure. We had a 180 CFM compressor and found that it wasn't enough for efficient operation. It worked but was too slow and ran too rich - it consumed too much media with un-intuitively slows things down. We now have 475 (which should be enough for two blasters) and it works properly. What happened at the lower CFM is you can't get the mixture lean enough so much of the abrasive travelling toward the work ends up colliding with abrasive that has bounced off the work. Blasting ends taking way longer and you go through tons more media, literally.
Granted you don't need the through put for hobby stuff, but still, it'll be very frustrating without a pressurized pot and it just takes a lot of air. iirc, a lot of these small compressors have a 50% duty cyle so you'll blasing a small percentge of the time waiting for the tank the charge.
We use black beauty or white lightening which are supposed to be low in silica (that's the health risk not silicone, and its bad stuff) I don't think glass gets you away from the issue (still comes from sand, right?) and I recall hearing it doesn't cut well at all ..... ends up being more time, media and more fuel for the compressor. The recycle centre thought it a great idea for a product from waste, but the guys who know more than I don't want to use it because it doesn't cut well/is slow.
As for air, the only acceptable set up imo is a positive pressue hood fed from an oiless air compressor operting well away from the plume. You just don't want to breath this stuff. If doing so indoors, very quickly, you'll have a hard time seeing from the dust. Commercial indoor units I've seen have significant air make up capabilty, but that is really big bucks and not feasible ( for either of us). I like the roll up doors at both ends idea, a breezy day might also be good. This is assuming your having at it with a good size compressor.
Give some thought to sand disposal. We'll only blast new steel fabrication as the sand with the scale is no big deal to get rid of. That is not the case blasting older stuff and we don't want the lead from the paint or whaterever else is getting into the yard.
Last point is, on a lot of these nice of old lathes, there has been time put into filling and finishing the casting. That gets blasted away and could add to the work you have to do. Why blasing instead of sanding? Not saying blasting isn't the right option for this lathe, but that it does have that downside if most of the paint still has good adhesion.
Looking forward to seeing how it all works out.
