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Working on a new tiny shop
awemawson:
I'm sure some will Russell, but think of Petrobond type oil sands that specifically add hydrocarbons for a bond. Only the tiny bit close to the surface actually is burnt, and the products of combustion form a gas shield.
Coal dust used to be added to sand for iron casting to improve surface finish. The coal burnt producing gases that again formed a shield and not only protected the sand but averaged out the surface finish.
vtsteam:
I sent for one of these heaters to try out:
http://www.amazon.com/Hydor-50w-Hydrokable-Substrate-Heater/dp/B0006JLPGS
Think I'll test it over a day, checking temps (without a thermostat) first. If it's sufficient to defrost and not too warm,
I'd like to use a 24 hour timer. Then I'd just hit the timer the night before I want to cast.
vtsteam:
Guys, I don't know about the properties of antifreeze exposed in a mold to 1100 deg F aluminum, or the effects of salt and or glycol on molding sand physical properties, but one thing I do know: the last thing I want to do is dip my hands into a tub of subfreezing molding sand laced with antifreeze or salt to fill and ram a flask!
I'll take warm clean classically tempered sand any day, and I have a feeling a sub freezing chilled mold would exaggerate casting difficulties as well. Handling properly tempered sand is a pleasure itself.
For winter casting, heat has it all over chemicals in this tiny shop!
mattinker:
I'm not a chemist, but a ceramist friend of mine warned against heating common salt as chlorine gas can be produced!
Regards, Matthew
JohnHaine:
Matt, as salt is used in molten form for heat treating, I don't actually think this can be true. Chlorine and sodium are two of the most reactive things around, it will take a lot to persuade them to dissociate.
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