Club 80-90 Forums

I'm about to tackle some minor rust bubbling on panels/seams. What's the best medium for this. Sandpaper which grit, or wire brush or something else?

I'll be rollering rust oleum once all the prep is done

Rake out the seams as deep as you can. Use a Stanley blade, wire wheel, 60/80 grit sandpaper, grit blaster if you have one. Then acid treat with phosphoric acid, epoxy primer,then rustoleum.

You really need to get to the back of the seams where possible.

Thanks for replies. I've taken back the paint around the rear near side panel and found nice shiny bare metal with patches of black pitted areas. Looks like someone has been down here before with anti rust treatment.
I can't really afford to replace panels, there are no holes, just pitted spots, looks pretty solid still. Can't tell what's going on behind as a PO has splashed waxoyl everywhere.
My next question is how do you build up smooth with filler without filling the seams, is there a technique to this? The pitted areas are smack bang next to the seams.

I'm taking the plunge with rustoleum. V nervous but what can go wrong?

Just need to make it tidy with filler beforehand.

Well the problem with rust is that it's hard to know how bad it is until you remove it all. Like when you grit blast all of those black bits out of the pitted metal, chances are you may well have pinholes. If you can't afford to replace panels yet or dont intend grit blasting, just acid treat it and cover it with a thin smear of liquid fibreglass, then a thin skim of filler over that. It's hard to fill next to the seams. Best technique I've found is to level out the filler, then pull a clean spreader down the seam to create a line. Then leave it alone to set or you'll make it worse. Then it down to sanding afterwards.

The Way to level out filler is to use a sanding block and sand the filler with nothing less than p80 grit. For the final skim finish with P180 grit so that the primer and topcoat have a decent chance of looking smooth with no imperfections or sanding marks. If you dig out a lot of sealer in the seam it's best to re seal the joint. Just run some sealer down the joint between the priming and topcoat stage and smooth off with your finger. As a rule if you pop the rust bubbles and water emerges,then this is a sign that you have pinholes in your metal and water is coming from the rear of the panel.

You can see the black pitted areas. What's the verdict?

Rule of thumb with rust is that there will be more that's hidden than what is visible. Personally, I'd cut the arch off and replace it but that's all well and good if you can do that sort of work.

So, for starters, I'd suggest that you sand back the paint another couple of inches so that you have a clear picture. You look to have a lot of refinish paint on there, probably cellulose because of the way the paint looks to have smeared from the sanding. Try using something more coarse, like a p36 grit. It's more aggressive but less likely to clog. Then progressively feather the edges of paint back with p60, 80, 120, 180 grits to get a smooth edge. Golden rule is that if your fingers can feel an edge, however slight, your eyes shall see it. If using body filler, buy the best you can afford, like plastic padding p100 grade as it's super-fine and sands with ease. Use p60 or 80 grit on that, with a rubber block so you get a flat finish.

When doing your repairs and try to see if you can also get to the rear of the panel so that you can treat the inside as rust, if starved of oxygen, has less chance to spread. Once done, I'd use an etch primer on the clean bright metal surrounding the repairs then a high build primer-primer-filler and then your topcoat colour. The primer-filler should be flatted with a rubber block using p320 onto 400, 600 grit wet or dry paper for a perfect finish. Don't just use your fingers to flat fillers or paint, you shall leave minute finger--lines which will show in the finished job.

Take your time, read up on any health and safety data sheets with filler and paints, wear a suitable dust mask, etc etc .

Definately pinholes beneath that black rust. You need to get rid of all of that black rust...only way really without cutting out the whole section is to grit blast it. Some people would be happy to treat the rust to slow it down a bit and filler over it.

boatbuilder wrote:Some people would be happy to treat the rust to slow it down a bit and filler over it.

Judging by all that paint on the panel, that's exactly what's been done before. I've just replaced the arch on my van which had very similar looking rust damage hence my suggesting it gets replaced instead and be rid of the problem.

Any ideas what sort of cost to replace the affected panels with new. I think I am realistically looking at arch, rear panel and panel above arch on near and offside. And do you knowanyone in or near Lincolnshire that is recommended.