Errr....
Quicklime==calcium oxide slaked lime==calcium hydroxide limestone==calcium carbonate
Mark Rand (who got into a fight in a pub quiz over this one:-) RTFM
PS. A though for the OP. Would a blow lamp and paint scraper be the best things to use to start with, before finishing off with the blasting?
But the big question is, did you win the fight?
Not to go off on a tangent (well, I guess we're going off on a tangent...), but one difference between the slaked lime sold for plastering and the fully hydrated lime often sold as "powdered limestone," "ground limestone," or "builder's lime" is that the magnesium oxide (and sometimes aluminum oxide), as well as the calcium oxide, has been full hydrated in the latter types. It's still waiting for some carbon before it's restored to limestone; much "ground limestone" really is just ground limestone, calcium carbonate.
It's amazing how complicated lime can be, as a building product. Don't ask how I know. It was a sad wall-restoration story.
Ed Huntress
Don't use anything that doesn't go away of it's own accord. Use the CO2, or just use a wire brush....
Don't blow crap up under the saddle that won't go away.... That includes chips with an air gun.....
I've done a lot of blasting with Armex baking soda. The baking soda used for blasting is larger, feels like salt rather than powder. It costs about 50 cents a pound. It has good grease/tar removal properties, but creates a real white dust storm even using a mist suppression nozzle. You need a very good metering valve to use the baking soda efficiently. I wouldn't go near an assembled lathe with the process, since everything that comes off the lathe will end up getting blown inside something. I wouldn't blast anything near the ways of a machine, even "soft" blasting processes are still abrasive. The alkalinity can be a problem for some materials, such as polished aluminum, or even painted surfaces that just get wet with the baking soda. It would probably be OK for disassembled parts, but relatively slow unless you use a lot of pressure and soda. It is not widely used in car stripping any more due to the tendency for soda to get lodged in crevices. Plastic Media Blasting or walnut shells are another way to go, I may try some this summer. Plastic media requires recycling due to its high cost per pound.
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