I got a used car with very minor surface rust. It's so minor that I think just sanding it will do. However, I'm not sure what to do afterwards. Don't factory metals contain some finish? If so, sanding the rust off will sand the finish off too, right?

I want to do the minimum amount of "covering up" the rust. I've seen people spray some black stuff, but I want to stay away from this. I've seen undercarriages as old as 2000 that looks almost brand new. That's my goal.

BTW if you have recommendations on the sanding method, I'm all ears. I don't mind making some purchases.

  • Once cleaned, bitumastic coatings are popular due to the flexible nature ie resistance to stone impacts.
    – Solar Mike
    Jul 9, 2021 at 4:41
  • Can you add a photo of the area?
    – HandyHowie
    Jul 9, 2021 at 11:03
  • @HandyHowie imgur.com/a/k5iVU3f Jul 9, 2021 at 22:14

1 Answer 1


Looks like your vehicle has a separate chassis and is not a monocoque design. The chassis will be made from thicker steel than the rest of the body and the small amount of rust that is visible is nothing to worry about, especially if you live in a dry climate.

It will be fairly difficult to remove all of it if you are thinking about just using some sand paper, since the rust appears to be mainly where the pressed metal is joined together and welded.

If I were removing this rust, I would use a wire brush on an angle grinder to get into the corners well, but even then it will be difficult getting to the top of the chassis.

To make the finish look original is going to be hard work, using rust converter, then building up the layers of paint, but you will find that there will be rust in the seams that will eventually come back through.

You could give the rusty bits a rub down with a hand held wire brush to remove any loose rust then brush on some underseal to protect the whole chassis. This waxoyl underseal is what I would use. It won’t look original, but it will protect the chassis well.

It would also be a good idea to spray some similar protection inside the chassis through some of the holes in the chassis. You need to do this only when you know the chassis is totally dry inside.

  • Thanks. It's a 20 year old land cruiser. I plan to get a full restoration done to it in a couple of years. In the meantime, I plan to use a wax-like spray, CRC heavy duty corrosion inhibiter. Should I still shave off the rusty bits before applying it? My concern is that once I use wire wheel, it'll become even more vulnerable to oxidation (larger surface area). I worry that I might miss a spot with the spray, or the application comes off. Jul 10, 2021 at 12:12
  • If that is all the corrosion it has after 20 years, then it isn’t rusting very quickly. I would just give it a light wire brushing where necessary, then apply the wax. I don’t think it is going to start rusting quickly if it is still being kept in the same climate a the last 20 years. Just check it now and then and add more wax if necessary.
    – HandyHowie
    Jul 10, 2021 at 14:51

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