Question to 2CV-L
I expect to be starting on my first renovation soon. I would like to know the best way to treat body rust. Is it possible to treat it so that it never returns?
Hi colin, to be honest, cleaning the car of all the paint is a lot of work. I don't know what your plans in restauration are, to completely build up a new car or the fix a old car. I did the last thing so to say. And rust treatment which has succesful till so far, is done with owatrol on places that rusted. First i cleaned it, than welded it and put owatrol on it, it works great. I've tried it on two different spots, one spot without welding, this part has stopped rusting, and one part where i welded, and it also stopped rusting. You do see traces of owatrol on the paint, but you can first put owatrol on the spots, than put primer on it and than paint it, than it will be alright.
Fact: rust never sleeps.
You cannot stop rust, but you can slow down the forming of rust quite a lot. Also, there are many myths about how to fight rust, so you will have to use your own head aswell as listen to others, me included. Ads showing products that stops rust, are lying. Period!
Several ways of avoiding rust: 1) Don't use iron, steel etc. 2) Use only type A4 rustproof steel 3) Use A2 rustproof steel. 4) Use galvanised steel, or galvanise the steel you want to protect. 5) Cover the steel with durable oil, and make sure it's covered at all times in fresh oil.
The above isn't always wanted or possible on your car. So; - Do not take away paint which is working, meaning; no rust underneath. Paint over it with the correct type of paint (2-pack prefeably). - Do remove all paint and rust in places with rust or where you suspect rust (blisters, "worms", holes etc) - Where possible, use zink on the steel. Especially where the paint will probably be scraped off when in use. Hinges and stuff. Zink is almost impossible to paint on top of without the paint flaking off, so avoid that. Use a thick oil or wax on top of the zink. - Use oil in all places where there might be condensation - all rooms, corners etc. closed or not. The oil has to be changed/renewed once in awhile - several years between is sufficient most places. But, if you squirt oil in there often, it's only for the good. The oil has to stay liquid! Adding wax in the same places is ok, if the wax is there to hold the oil in place. Oil keeps oxygene away from the steel. For wax to be able to do that, you'll have to polish it on painted or spotless steel. If rust has already started, wax has little effect, oil has.
Underneath the car you need something to keep the oily slush in place. Oil mixed with wax can do that. Or, the old method, oil mixed with dust and sand... It works!! If the car is completely new and guarantied without rust (no second hand car is), it's even possible to put Blackson or similar on. Or even silicone like stuff. This has to be put on a prepared surface that is well protected from rust already, and will hopefully protect against chipping because of little stones etc. If water gets under this silicone or seem sealer or whatever, the steel sheets are deamed.
Whole floors in several 2CVs I've bought have fallen out, litterally, after being treated with silicone. That's cured silicone, the firm stuff similar to the sealing stuff used in bathrooms. Liquid silicone, on the other hand, is totally different. A very good rust preventive, but it's impossible to paint the car where that silicone is used. On electrical stuff, rubber parts etc it's perfect - a little expensive though. All sorts of plastics are steel killers aswell.
If you repair an area that has been rusted, sandblast the naked steel just before you prime it. And finish the priming and painting. The primer lets oxygene through too, so several layers are needed. Polish the top after curing, to fill the last pores.
Bear this in mind:
How bad a car rusts, is totally dependent of where the car is. Dry highlands, or near the
sea front. Salt used on the roads in the winter or not. And of course, less or more rain
during the year. Stays the nights in a garage or not. Temperature going up and down a lot
or not. Etc. If you live in a fairly dry area without salt, do whatever the rust
preventive manufacturers say. It'll be ok. If you live in a wet, salty area and have to
have the car outside a lot - then use oil, oil, oil and oil. And be very careful when
fixing things, welding etc.
In the middle of France one doesn't need rust preventives to make a car last 20 years. In Denmark it's enough to say "boooh" to a car and it rusts through. I think Kim said the only way is to galvanise it. or make new body parts once in awhile.
PS: the above looks worse than it is. I only meant to write a few words, but got carried away. Except for being a dirty and sticky job, it's quite straightforward.
As for Owatrol that Niko mentiones, I think of it like wax - only thinner when you put it on. It hardens after awhile. It is possible to paint on top of Owatrol, with White Spirit based paints. Or you can even mix those paints with Owatrol - you get a fantastically shiny finish. The etching and priming you mention, ok. Just don't let any fat or silicone near it - don't use White Spirit like thinners to clean the area. Use a proper thinner.
6) Re - wire vehicle totally and do away with negative ground system which encourages rust formation.
Rust can never be stopped IMHO. Take one new front 2CV bumper. Have it sandblasted. Then treat with phosphoric acid, etching prime, powder coat, waxoil. It still rusts. Just do as no doubt millions will tell you and you'll stave it off for a few years, but you won't stop it completely.
I am going the galvanizing route wherever I can to help battle the rust beasties. I had the rims and bumpers galvanized last year and am very happy with them. Currently, there is a SLC galvanized chassis on its way over in a container for the big restoration project this year. I can't get away with galvanizing as much on the 2CV as we did on the Land Rover, but I have a few more pieces in mind before the end of the project. The body is a whole different story....