I have an old fashoned water bath with evaporative elements standing in it. I also have a large kettle on my stove on low heat at all times steaming away. I keep the heat low enough that if it dries up and I don't realize it, it doesn't do anything drastic.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.