I’m looking for technical help or recommendations on: slight arch rust
I apologise as I know this will be covered somewhere but couldn’t find exactly what I was after.
My 2011 NC has a slight rust line on the rear arch I would like to improve. The car has had underside treatment since I’ve owned it and it hasn’t got worse on the arch. It is about 3mm wide starting on the very inside of the wheel arch. Having a feel it feels very solid.
Am I naive in thinking I could sand, convert, prime and aerosol a small repair (masking up the outer part of the arch).
Any help and recommendations on products is appreciated!
Can you upload a photo Craig? I think I know the area you mean and took a similar approach with my NC2, but just want to be sure I’m thinking of the same area.
I think I know the area you mean, check out the rear arch lip on this NC below. I had a couple of very minor rust patches a little edge corrosion on the lip. I could have spot painted it but it needed grinding back first to remove the surface bubbling. I decided to get the rust treated, painted with a suitable rust converter, then painted over with Bilt Hamber black epoxy. All masked up I painted the whole lip about 10mm in. The black epoxy, then grey primer, a few coats to cover the black, then finished in a few coats of body colour.
All being sanded back a little between coats to leave a smooth finish. Finished off with a lacquer coating.
Nearly 3 years still looking rust free when I sold the car. You have to look close to see the paint join.
I also used the Bilt Hamber to coat the inside of the lip, wheel arch liners out then sprayed over with Dinitrol underbody seal.
Yep, same area. On mine it was a slightly wider area onto the arch and I took a very similar approach to Mick.
Masked off, took a wire wheel to the area, then sanded, cleaned back and applied BH Hydrate-80. A couple of coats and left to dry. Then BH epoxy, grey primer and finally colour.
Not sure I have a suitable reference photo any more, but this is the best I can find:
I used Hydrate 80 same as Wardy or I have an Hammerite alternative Kurust, which are all much the same. Paint on rust it turns a blue ish colour then paint on your primer or for me the epoxy black then primer.
Do these converters actually work though or does it just come back through eventually?
There are some liquid rust removal products out there that may be better.
Yes on light rust, not so much on heavy crusty stuff.
I’ve used it in both situations and ended up retreating crusty chassis rust.
I don’t think much works and stops rust, maybe in marine applications I’ve heard, even they need retreatment. Grind back to shiny metal if you can and slap as much treatment on then paint is what I do. Inspect annually and if needed retreat.
I reckon so grey will be fine,it’s only in the wheel arch so not noticeable so much as on a main body panel.
Plenty of top finish coats should cover it fine. I’d wait until the weather is milder before doing the job, plenty of moisture in the air and cold, doesn’t make for a decent paint/repair job unless you’ve got a heated garage to work in.
