Rust question

[Shep]

I have a question about rust for any guys (or girls) that know a thing or 2 about panel beating/body work. If you just treat it without actually cutting it out is it just a matter of time before it comes back or can it ever work for good if you treat and repaint?

[Lumen Miner]

I like to think of rust as malignate cancer. It is almost akin to a living organism feeding on the metal and accelerated by moisture.
If you remove any rust that may come loose later, then sand to a solid structure, then treat you may stop it coming back for many years or at all.
If you leave / don't remove the excess flakes and it is still getting moisture, then it will come back, it may brood under the surface for a while until it recieves enough moisture to accelerate the bloom.

I have left oranage surface rust then threated it with phosphoric acid, sold as "rust converter" in home DiY stores. It hasn't bloomed again in several years, yet would if it was still getting moisture from somewhere.

The trick is to eliminate the accelerator which is water / moisture.

[Louwai]

THe "Rust Converter" that Mitchell notes is not too bad. I had 1 particular VW Beetle for 14yrs. This was my "play" car. It spent it's life on the beach & being driven through salt water etc. I'd always hose the car out after being on the beach, but every 6mths or so I'd look for rust, paint any that I found with "Rust Converter" & after it dried, plaster the entire car with fisholine.

It lasted me 14yrs & then I sold it. I think it may still be getting around somewhere....

[Shep]

Hmmmm, well I was asking because I did some rust in my car myself, I wanted to save some money and its just an older hyundai excel so doesnt matter if the finish doesnt look perfect. I did some of it a couple of years ago which has come back but other parts I did haven't returned, for sure the bits that have come back have had more water tho, one bit in particluar was really bad where water was pooling on the boot floor again (It took me a while to notice that it was leaking again DOH!!!!) so in theory hopefully if I remember to check more regularly that the boot isn't leaking then maybe i'll get a lot longer out of this round! Hopefully anyway coz it sure is a sucky job to do! ;)

[el_draco]

Eh hem:
Chemistry Lesson (somewhat abreviated): Rust requires an electrolyte (salt), metal, oxygen and water. Eliminate any one of them and you get little or no rust.

If you clean the rusted area then seal it so that there is no oxygen, water or electrolyte contact with the metal... no rust. Good ol fish oil will do it internally on doors etc but outside is treat and seal territory. Hope this helps.

[GeoffW1]

Hi,

Scrape it back as well as you can and then paint well (or spray) with fish oil. There is a type which is deodourised.

After it dries thoroughly you can paint the surface, which gives added protection.

It must be said though that if the fishoiled surface is constantly wet it will eventually need re-treatment. Painting after will delay that.

Cheers