levy@ttrdc.UUCP (Daniel R. Levy) (12/07/85)
In article <638@isrnix.UUCP>, greg@isrnix.UUCP (Gregory Travis) writes: > >On another note - does anyone know why USED motor oil is supposed to >be such a great rust inhibitor (apart from oil's ability to simply >displace water)? My '70 Volvo 145 is beginning to rust in crevices >on the body (under floormats, in gas tank compartment, etc..) and >short of welding new metal I want to at least slow the rust to a >negligible pace (some of it is in very difficult to get to places - hence >my desire for something I can simply spray at the rust). Anyone have >some good ideas? >-- > Gregory R. Travis While I can't say that I _KNOW_, I think I have a good guess. The used oil has a small amount of solvent (gasoline) suspended in it, which might make it better for soaking into all the crevices of a rusted surface than new oil (the rust flakes and metal itself are "wetted" better). Some brands of rust-inhib- itive paints (Rust-Oleum?) contain fish oils which are supposed to have the same quality. If the surface is well "wetted", it seems likely that there is less chance for oil-less areas to become exposed and to allow further corrosion. I have read (from a chemistry text I used in undergrad school) that a partial covering of a rusty area is actually worse for propagation of rust than no covering at all, so maybe this has something to do with it.... Maybe if a little gas was well mixed with new motor oil, the results would be similar? Anyhow, it does sound like a better use for old motor oil than just pitching it out (though a little would go a LONG way). -- ------------------------------- Disclaimer: The views contained herein are | dan levy | yvel nad | my own and are not at all those of my em- | an engihacker @ | ployer or the administrator of any computer | at&t computer systems division | upon which I may hack. | skokie, illinois | -------------------------------- Path: ..!ihnp4!ttrdc!levy