http://owatrol.com/en/all-our-products/7936-owatrol-oil.html should turn them into an outdoor version.
When I was young and stupid I bought a car that, according to the one who sold it to me, 'needs 2-3 welding jobs'. About a year later I went on to do them and by god, yes it did: front third, middle third and back third... It nearly broke apart when hoisted up - but 3 months, 7 repair panels and ~1.5m² of thin sheet metal later it had regained all the structural integrity it had lost (it was an integral body frame chassis). Was an interesting learning experience but I wouldn't want to do it again, ever.
Got its good vehicle test certificate (in a fair inspection, not through bribes) and the engineer was impressed by the work, which he could easily inspect as I had ran out of free money to dump into optics so there was no top coat, no primer, no putty,
nada on the repaired areas - naked shining metal with the weldings flattened by an angle grinder was all to see. What one couldn't see (that good, as it only gives a slight honey tint) was a single coat of brushed on Owatrol Oil.
And as of financial reasons, a youthful 'f..k it' attitude and it looking interesting enough to be a good conversion starter it stayed that way in the 4 years that I kept it, every police stop was mine to take but always ended without objections (even with the car visually going Blues Brothers every second now, at first glance) so I always was on my merry way in short time. No single sign of corrosion, no spot with rust on the repaired areas (some crept up on other, untouched parts like the used bought replacement hood and doors), outside the whole year 24/7, still the look of naked shiny metal with the weldings flattened by an angle grinder. The guy I sold it to sanded down the rest of the body, applied putty, primer and topcoat so it looked like new (sans the used interior) and it stayed that way for another ~5 years (then I relocated and lost track of him and my car).
Long story short: Owatrol Oil is great, if I have metal parts I don't want to corrode (or stop from continuing): brush it on and done.
Only downside I found is that it has a slight sticky feeling after being dried and takes a good while to do so.
Oh, it works on wood too
