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Hi, Well, you got that right. Regular sand, play or not, is about the worst possible product you could use for sandblasting, as far as safety goes. The only thing good about it is that it's cheap. Certainly, if you are going to use regular sand, the proper respiratory protection is positive pressure fresh air. In fact, I think it is really recommended for all blasting. That said though, I don't use my fresh air respirator for blasting. For one thing, I don't use regular sand. I use Black Beauty blast grit, a slag product with low free silica. It certainly is more expensive than sand. As I recall, the last I bought was about $7.50 for a 50# bag. But it's a lot safer. I only blast for my own use so I don't go through much and the cost is not a significant concern. I use a regular cartridge mask with prefilters for that, when blasting outside. Under a blast hood, of course. I don't know what the prefilter rating is. They are from DeVilbiss for spray painting but don't seem to have a particular rating on the box. When using my blast cabinet, I don't use anything. That uses Black Beauty grit also. The vacuum vent and filter assembly for it is from TP Tools, the cabinet manufacturer. It includes an optional final discharge filter. I don't know what the rating of it is. It appears to be a standard product from TP Tools so I am assuming it's adequate. They do note in their catalog not to use silica sand in any of their cabinets. I suppose that's a general recommendation anyway, mainly due to liability concerns. Of course in a cabinet, the grit is reused for quite a while so the cost is even less important. I think Black Beauty breaks down less than sand so it would last longer. I believe it also cuts better, but I have to admit to never using sand, so I can't say from experience. The few major industrial blast operations that I have seen did not use sand. They used Black Beauty grit. I used to work in a major industrial facility that went through many, many tons of Black Beauty a year - never used sand. Nevertheless, like with the ISOs, for personal use the selection of product and the protection used is an individual choice. Leave the sand for the sandbox and mortar/concrete mixes. Use something safer for blasting. Whatever respirator you wind up getting, make sure it has the capability to use replaceable particulate prefilters. I would recommend a regular cartridge type paint spray respirator as a minimum. Definitely not just the dust masks. The dust masks do not provide as good a face fit as a real respirator. They are mostly for nuisance dusts. Don't forget that blasting can produce other bad particulates besides silica. Even if you don't use sand, there are such things as lead-containing paint dusts that may be involved. If you must use sand, however, get yourself a positive pressure fresh air system. You'll find it of immense value anyway since it will permit to you safely use modern paint additives (hardeners) after your blasting jobs are done. Sorry, but there's nothing really "inexpensive" about any of this stuff. The only way to fly cheap and safe at the same time is with hand labor, old technology and a paint brush.  Rod
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