Rust protecting your car

[Mux213]

Hey Guys,

Since this keeps popping up again and again, and some people are busy with restoring their cars, let's talk abit abotu rust protection and properly painting your car.

Here is what I think of it from what I've read so far and based on my preperation work for the RX7:

First, stripping off the old paint layers.
Wirewheeling will only remove surface rust but always leaves visible or invisible rust behind.
Sandblasting is the prefered method that is still somewhat affordable, but even sandblasting can't get into hard to reach areas or can even damage the body work as its a pretty aggressive method or stripping paint.
Expensive but definately the best way (often done after getting most of the paint off by the forementioned methods) is to submerge the bodywork in an acid. Combined with an electrolitic process this removes EVERYTHING from the body work. The moment the body comes out of the acid bath it is completely clean. However 1 second later microscopic rust already forms, so even with this method getting the body primed asap is very importent.

Rust makes rust (rust is a catalist for the rusting process), any rust left underneath your paint job will soon cause more rust to develop. So lets look at the options once you have your car clean of the old paint and relatively rust free.

The most used with car restauration is just to apply a layer of primer. Primers main job is to uniformly coat the car in such a way that the color layer can stick to it very well. Normal color paints don't adhere that well to steel. In the early days this was even so that the primers used where porious because the top coat stuck better to it. It was the top coat that closed the steel off from harmfull outside air! Using an old primer and waiting with the topcoat for a couple of days was a sure bet to get a major rustproblem within weeks.

Today most primers completely seal the steel from harmfull influences however you still need to worry about what was already there. If (invisible) rust is already on your body work (which in 99% of the cases is so) it will find a way to continue rusting nicely underneath your perfect primer layer This is why most primers these days contain etching qualities. This causes any microscopic rust to be 'neutralized' (convert rust molecules into something harmless by a chemical process) however larger chuncks of rust is to much for it to handle.
Also something to keep in mind is due to environmental reasons, most new primers use water based solvents. They evaporate moisture to cure. When you use such primers in a normal DIY environment the curing process takes a relatively long time and the evaporated moisture itself could become a source for rust to develop.
In the end, sandblasting your car, painting it with a good etching primer preferably in a heated environment, keeps your car rustfree for years. Even in DIY conditions there is a good chance you wont see rust for many years.

If you've wirewheeled your surface you can also go the fertran route, fertran is a substance that also neutralizes rust, but you have to wash it off afterwards and then use a primer but it gets your body work into a state where the etching compound in a primer is enough to handle whatever is left behind. Fertran works similar to an etching compound converting any left behind rust into something harmless.

Then you have products like POR15 or Rustbullet that come out of tests very very good. They are chemical based primer coats that cure on moisture instead of evaporating moisture. They also penetrate the rust layers and adhere to the steel surface underneath the rust effectively closing the steel off to outside influences. They also keep moisture away from the steel during the curing process as the moisture is used for the curing process. But they are much $$$, probably one of the most expensive ways to treat your car in a DIY manner.

Last but not least, the most effective way known to me is galvanising (or zink coating). No I don't mean those cheapo zink spray cans you can get at your DIY store. This is a process that continues on the acid bath process. In the acid bath electric current is added to 'extract' the oxigen attoms from the rust molecules (electrolitic process). Right after this process the body is moved into another acid bath where the current is reversed and zink is added. The zink electroliticaly adheres to the steel giving a life long protective layer to your steel.

Interestingly enough, I've been trying to get in touch with a guy that claimed on the internet that he did a DIY version of this process for a frame of an MG. Our hachi's are to big (you'd have to build a kickass tank) but an MG frame (or a Delorean frame for that matter) is small enough to create a low bath that holds a salt watter solution. This wont 'eat away' at paint like acid does, but it does allow you to do electrolitic process to treat the rust and then galvanise the frame.
There is one major issue to overcome here. Its highly illegal to do this process at such a scale (anyone can buy small galvanising kits to galvanise cutlery and small metal items like coins).

Owh, a friend of mine has a quote out on doing this process at a company for his Delorean frame, costs around 5000 euros. Doing a hachi probably goes over 10.000 euros.