when I had my 79 Cobra I would squirt oil from
a hand pump can in the doors and in the quarters
about twice a year and it worked great. I would
use the old oil that I drained from the engine.
On the down side you have oil driping from all
over the car so you have to watch where you park
for a few days. There use to be a company called
"Rust Check" ,rust protection for old cars which
was basicly what I was doing. It works!
years ago i had a buddy whos father would take 90 wt gear lube(i think), heat it on a hot plate, and had some sort of sprayer that he would put it in, and spay inside the doors, fenders, 1/4's etc..had an old (1965 i believe) dodge pick-up that he did it to once a year(bought it new)and other than a few days of having to park in the street because of the oil dripping, it seemed to work great..looks as good the last time i saw it (couple years ago) as it did the day he bought it..he would only spray on a fine mist of it..dont know if it would hurt anything else..rubber ect..but seemed to work on stopping the rust..and here in ohio, thats hard to do..lol..good luck............. joe
Any oil will work to keep rust from forming on bare metal. you also have to keep in mind that its not going to stay on there as well as a spray on bed liner with adhesives in it. also, if your driving it, every speck of dirt that passes near the oiled surfaces will stick, and you will end up with a thick black goo... which i would imagine would still keep the rust away, but it is going to look just as ugly as a under coating. im not quite sure if i just finished stating the obvious, or it actually helped you, but good luck either way you go.
Up here in Canada just about everyone gets their car rustproofed.Some use oils and some shops offer drip free materials which all seem to work good. As MrSiv just mentioned on the previous note, the only disadvantage is that it looks real bad after the dust and dirt sticks to it.The other thing that I don't like is that when you have to do work on your car, you come out with this oily stuff all over you.
Haven't read about many auto applications of this, and in CA it's unneeded, but you could reduce/stop corrosion with cathodic protection. A less "noble" metal like aluminum or zinc, in spray or bar form, is attached to the body and grounded to an earth ground like a water pipe when parked. Water heaters, steel ships and pipelines use sacrificial magnesium/zinc anodes like this. Anybody heard of this used for cars? I think I've seen impressed current devices for stored cars, that you plug in, same principle.
What Ken66 is saying I think is in the JC Whitney catalog.
In my aircraft I use "Corrosion X" or "Boeing T-9" which works well and isn't too messy. T-9 has some kind of parrifin quality and is fairly clean and can be purchased at aircraft supply houses in spray can. Boeing uses it so must be good. Don't normally rust but corrode. Think its still good.
Try 3M "rust fighter".It sprays out like oil to soak into cracks and crevices and then overnight it dries to a wax like consistency.No drips after that.You can get it at any Napa store or any body shop supply that sells 3M products...
I live in Montreal (Quebec - Canada) and the city and provincial road dept still go hog wild with salt in the winter although somewhat less than they used to for environmental reasons. I bring my '87 Chevy Cavalier Z-24 to a rust proofing chain (Rust Check) every October for a re-coating of rust proofing oil. I have been doing this since I bought the car new and there is absolutely no rust on the car (and it DOES go out in the salt bath during the winter). Prior to bringing the car in, I do my best to clean the undercariage with the garden hose, let dry for 2-3 days then bring it in to one of the Rust Check franchises. They have 2 levels of rust proofing : the $50 or so one, and the $110 (CDN) one. I always went with the more expensive one and I give the spray technician a generous tip so he dosen't skimp on the quantity of rustproofing oil he applies. On the $110 application he sprays a redish color "lighter" oil in all the inside cavities (doors, etc.). It smells like cheries and is like a thick WD-40 oil. A much more thicker and black color oil is sprayed on the undercariage (this black stuff was introduced about 2 years ago and stick longer to the undercariage than the red oil). I leave the car outside for a few days while it finishes dripping oil on a cardboard, then wash the car. A US friend of mine said there are no such rust proofing by oil franchises in the US because the EPA wouldn't allow it.??? Anyways, the Rust Check oil works on my car and I'll have my '66 Mustang coupe sprayed when its restoration will be finished.