Painting rusty bits to protect an older car.

[e-honda]

I've got an R53 Mini, it used to be a modern car but somehow it is now 20 years old.

The body work on top is in fair condition, but underneath it's starting to look pretty rotten. Its all surface rust really, on stuff like subframes and wishbones etc. I want to prevent it from getting worse, I am not worried about what it looks like and I am not trying to dress it up to sell, I just want to protect it.
It's been in the garage for a couple of years but I want to make room for something else so will go back to being outside.

If I start getting a wire brush out cleaning it, putting rust eater on it and painting with hammerite or something will that generally help even if it's not a brilliant job? Or is it a case that if you don't do it properly taking everything apart and being methodical you do more harm than good.

[GreenV8S]

e-honda said:

If I start getting a wire brush out cleaning it, putting rust eater on it and painting with hammerite or something will that generally help

Yes, that's a perfactly practical plan. I assume the rust eater you have in mind is phosphoric acid based or similar - this leaves a layer of protection when it's finished reacting. There are various paint products that offer more or less protection against chipping. Hammerite isn't the best or the worst.

[Lincsls1]

Depending on how much you'd be willing to spend...

https://www.jrclassics.co.uk/procedure

I've just had my Monaro done, he did a fantastic job and a much better one than possible on a driveway or in a home garage on axle stands.
Otherwise your DIY approach is sound, but in practice a ball ache to do.

[Belle427]

Using a good quality spray underbody wax may be easier once you have cleaned up and treated the rust.
It's easier to get it to parts you can't paint.
Depends how much time you want to put into it.

[Peanut Gallery]

I do recommend Preserve and Protect - they are near Glasgow. Are happy to weld up, gave my car a real good going over. Each car is different but if you send them pictures they can give you guidelines before you drive up and leave your car with them for about a week. They were booked up for a good year into the future, so don't just drive up in the hope!

[tapkaJohnD]

In the old days, used engine oil sprayed onto the underside was used, but that's a bit H&E-verboten these days.

Just Waxoyl it? https://www.ebay.co.uk/itm/185914759505?epid=23032...

John

[steveo3002]

lanogaurd and bilt hamber get good reviews , idealy get under it for a good look around every summer , dont be thinking one application will have it sorted for the next 10 years

[Smint]

Wire brush it, treat existing rust with whichever rust converter you prefer.
Paint over that now treated rust.
As a final treatment i'd spray the whole underside, cavities and in all nooks and crannies with something oil based which will seep into seams etc, i use ACF50 which some people swear by and others say different, once you've done the main work an annual recoat with ACF50 takes about 20 minutes.