I have a Kool-Mist Portamist that I move between my lathe and mill. It makes a huge difference in tool life. I run it with a 2 cylinder airless compressor. It is heftier than a little pancake, but does not have enough to run even a small spray gun. The compressor cycles frequently, but does keep up. I have not had a rust problem with the Kool-Mist coolant, but it will stain if left overnight. It works best if used frequently, and with the Kool-Mist coolant. I made the mistake of getting some Enco coolant and have been having trouble with the mister ever since.