Originally Posted by
spumco
I have serious rust problems in my shop and have tried quite a few things, including Fluid film.
I've used it on my mill and lathe - acceptable results in between machining sessions. However, it does not hold up to flood or mist coolant and you lose the protection - this is with two different brands/grades of coolant. Also keep in mind that fluid film is not an appropriate lubricant for ways or ballscrews - you need way oil or some other load-bearing lubricant.
I've since switched to Spray-on indoor metal protectant (LU-767). This seems to work significantly better, although switching to a different coolant and using distilled water probably made a bigger difference on my mill. Much easier to apply than fluid film and it dries to a soft dry-ish film that doesn't seem to build up or get gloppy.
For longer-term rust protection Spray-on and other companies make long-term outdoor-rated rust protection products. These are all, as far as I can tell, basically a wax in a solvent. Wets out on the surface and creeps in to crevices and then when it dries it forms a semi-hard wax. This stuff is superb for avoiding rust, but the buildup can be annoying in certain applications.
The first (and last) time I used it on my mill table I carefully removed the wax from the table where I was working, but the hot chips embedded in the wax I didn't remove and simply wouldn't flush off with a washdown hose or air blast. Had to use a degreaser to clean the chips... But for a lathe faceplate that's going to sit for 6 months nothing beats it.
I still use fluid film around the shop, but not on the machine tools.