What To Put Over Metal

[jonj1611]

I am about to clean some rust with a wire brush, mainly surface rust. Its underneath the car. My question is what do I put over the metal after cleaning to protect it? And then do I need something on top of that?

Bit new to this but funds mean need to give it a go myself, any advice appreciated

[bradjmsn]

If its under the car get a very good underseal paint, hope it helps

Sent from my SM-G930F using Tapatalk

[jonj1611]

Does it need to be primed first?

[TomsFocus]

If it's hidden I'd just slap some Hammerite on it... Works as undercoat and top coat all in one. You can also get 'Stonechip' paint which is similar but tougher, it leaves a rough finish though.

[jonj1611]

Sounds ideal, something like this ? :-

https://www.halfords.com/motoring/paints-body-repair/rust-removal-treatment/hammerite-direct-to-rust-metal-paint-smooth-black-400ml

[TomsFocus]

9 minutes ago, jonj1611 said:

Sounds ideal, something like this ? :-

https://www.halfords.com/motoring/paints-body-repair/rust-removal-treatment/hammerite-direct-to-rust-metal-paint-smooth-black-400ml

Yep, that'll do!  I tend to buy it in a tin and brush it on though, much cheaper and no risk of overspray, obviously the finish is better with spray though so depends if it's going to be at all visible or not. 

Most of the DIY stores do their own equivalents as well.

 

[jonj1611]

Many thanks, will look for a tin I think, its under the car and no one will see it.

[Tizer]

I read a test years ago where two bits of sheet steel, one clean and one with surface rust were marked into sections and painted with different surface treatments, then left outside in an exposed location for almost a year. The one that performed the best was David's Zinc 182 primer. This was even better than  Hammerite.

I have used it myself since then on a number of old cars and around the house and have not had any complaints. It is sold as a primer that should be overcoated but In situations like yours I haven't bothered to overcoat it without any problems.

Obviously if it is rusting from the other side of the panel or very badly pitted then nothing will stop the rust coming back.

 

[Ian Lanc]

If it's well out of sight then use oil or grease, just slap in on, it's the best stuff to stop corrosion in it's tracks, if you want proof look at an old car and check out the oily engine bay, surrounding areas contaminated by old oil, the steel is mint, whereas the rest of the car is a rot box.