Filling and Sanding

Buford T Justice

Guys

Below is a pic of my camper conversion which is suffering a bit of tin worm, as you can see.

There is a hole behind the drivers door, and the arches are bubbling a bit and it all needs to be treated.

I'm not so concerned about getting the van painted or even part painted yet, but in regards to filling and sanding the holes, I do have a couple of questions.

What grade of sandpaper should i use, and where can I get it?
If I fill and sand the holes down smooth, is it detrimental to leave it with just primer as a coating for a while? Can't afford a paint job at the mo.
Are there any obvious things / pitfalls to be aware of here?
I have a tub of P38 Easy Sand for the filling.

Thanks guys

JabbaTheHut

You will have to use a couple of grades of sandpaper. You don't generally just put on the filler, and sand it with the finishing paper, unless the amount of filler is not too deep. Something like 180 grit of paper would do for your first sand down, which you should sand to have a very good, general shape of the body where you filled. You can always try some wet 400 grit paper if you feel it's right, to finish it off, otherwise, another skim of filler, and then some wet 400 paper.

You'll get the sandpaper at most motorfactors.

Priming the job, and leaving it is not ideal. If it's not covered well enough, some of the metal may start to rust again. If you wanted to be really safe, if you have any colour at all, you could cover it, until it's ready to give it a finish coat.

It's a while since I did this kind of work, so maybe someone else here might have a better suggestion.

Best of luck with the conversion, btw

Buford T Justice

Thanks. I can stick any old color on it if needs be. I'm thinking of just doing the bottom half of the van, I'm open to color suggestions btw.

I'll get some 120 180 & 400 grit then. Is it ok to use an orbital sander on it or should I do it by hand all the way?

JabbaTheHut

An orbital sander would be ok, but if the area is bigger that say, a square foot, it's be hard to keep it flat, and would stand out when you have the finish coat on. If you can feel "bumps" where there shouldn't be, then you know that they'll show more when you do have your finish coat on. Also, if, when you have the primer on, you look across the surface, you'd be able to see if it's flat or not.
You'd need sandpaper wrapped in something flat, to get a good flat finish. It's not the easiest job to do that in any case.

Oh yeah, I probably didn't explain properly enough. When you're happy with your filler, and you have it primed, you'll then need to use the wet 400 paper on it, just to take the roughness of it. Don't go too far and take the primer off, but if you don't do this, the final coat will look crap. No good after all the hassle you went through to do the job in the first place.

By the time you're finished, you'll be an expert on the work

Buford T Justice

Ah jaysis, I don't have that much rust to be filling. There's more rust on The van I drive on the road at the mo. ;-)

Spunj

It is pointless filling a rusty hole with any product. You need to cut out the cancer and weld in a piece of metal. then grind it flat. After that you can fill any blemishes.

The rust will just continue working under your filler if you don't.

The following I would never do, but if it's the only alternative to a blob of filler in a rusty hole, be my guest...

If you don't have access to a welder, cut a square around the rust till you get clean metal then drill and pop rivet a piece in, then tap it in a bit and fill over that. Prime all shiny metal with zinc-rich primer.

In any case, you should look at what caused the corrosion in that location, check for blocked drain holes or ingress from the wheel arch, or something closer. You'll probably find something nasty which will attack your new repair. Consider drilling a small hole and pumping in Dinitrol or Waxoyl etc after you are done, then treat with zinc-rich primer and close with a rubber bung.

That pic shows something similar near the rear wheel arch, surface showing rust like that is usually caused from the inside out.

A nice Zinc primer and a Halfords etc. shaky can of colour will cost little and be not nearly as noticeable as bubbling rust holes.

whizbang

Get some mirror effect blackout for the back windows, park it up beside the motorway, and Magic, your rust problem will disappear in a cloud of smoke.....
(make sure your fire & theft is paid up):D

Buford T Justice

whizbang wrote: »

Get some mirror effect blackout for the back windows, park it up beside the motorway, and Magic, your rust problem will disappear in a cloud of smoke.....
(make sure your fire & theft is paid up):D

Nice idea, but in fairness, its been 5 months of hard slog to build the van. Not going to cash in on it any time soon....

Can't face doing another one.

Buford T Justice

Spunj wrote: »

In any case, you should look at what caused the corrosion in that location, check for blocked drain holes or ingress from the wheel arch, or something closer. You'll probably find something nasty which will attack your new repair. Consider drilling a small hole and pumping in Dinitrol or Waxoyl etc after you are done, then treat with zinc-rich primer and close with a rubber bung.

I'm fairly confident that there is a leak in the seam between the GRP high top and the body, and its running down to that spot. I'll be resealing the whole rim soon with tigerseal.

The rust in the back arch - some of it is from the same issue, but there are other spots where the filler was just bubbling. Think i read somewhere that if it was filled to thick in one layer this happens, but i could have been dreaming that one.
Have filled again now 4 layers i think and fingers crossed the seal on the roof will do the trick.