Hi,

I have a van I am converting to a campervan. The van is in good condition but one thing troubles me - the roof struts\support cross members inside the roof have rust on the edges. See attached.

What would be the best thing to do with this please to get rid of the rust? Obviously, splitting all the spot welds in each support and rewelding after grinding off rust would be a mammoth task and would need to paint the entire roof again inside and out. So what would be the next best alternative?

Thanks in advance

Its interior rust Car trucks rust from inside out.
That's pretty minor really might be able to just scuff it with some Scotch brite soap and water? then seal it, the in between is what it is, its an older Van to start with the whole truck is gonna be that way in a lot more areas especially were you can see.

If you absolutely have to fix it I would sand it out or Wire wheel it or blast it with Glass then paint it with epoxy. Its a Band aid BUT To really do it right would probably be cost & time prohibitive.

I would not use Phosphoric Acid on it as it would damage the surrounding Paint plus the amount of water needed to rinse it off may do more damage than you want.

Thanks DoRight. So when you say Phosphoric Acid is this like rust converter products?

I was going to do something like what you suggested - use a wire wheel tool in drill to remove as much of rust as possible then coat it with a paintable rust inhibitor then paint it. would that be the best option?

When you said "seal it" - what exactly do you mean please? Seal it with what product?

Thanks

Agree. It's not that serious. Just clean up as best as possible and then seal with an epoxy undercoat/primer. This will stop moisture getting back on the metal and is much better than any "rust inhibitors".

Interesting observation here, and I've seen it before. Apart from the fact that manufacturers are less than generous with paint on the inside, I see that this seems to be more on areas which are the inside of exterior panels. It seems to happen less where there is another panel inside of the external one. So what's happening is that when the outside gets cold condensation forms on the underside of the external panel, where that underside is not protected in any way from the moisture laden warmer air inside the van. Creating what in building is called a "vapour barrier" will stop this and reduce the likelihood of recurrence. How? Just line the inside with ply and then insulate in the gap.

Yeah, it always seemed that simple as a kid to me as well. Our higher end trailers and RV units are constructed as Chris said. Why so many of these vans were made this way totally escaped me.....

JarFar wrote:Thanks DoRight. So when you say Phosphoric Acid is this like rust converter products?

I was going to do something like what you suggested - use a wire wheel tool in drill to remove as much of rust as possible then coat it with a paintable rust inhibitor then paint it. would that be the best option?

When you said "seal it" - what exactly do you mean please? Seal it with what product?

Thanks

Not really a rust converter but most of them do use phosphoric acid, You can also buy it strait For really bad pitted rust I use it strait. turns Iron oxide (Rust) into iron phosphate. (Black crust) most rust converters on the market are junk will damage paint and cause adhesion problems Most guys here do not use them I am one of the few, don't be-leave what you read about them on different web sights. All will claim to be paint-able BUT none are guarantied to be used under a paint system! and no paint company will say its ok under their paint system!

Only trust those made to be used under a Paint system! Axalta, Cromax, Dupont, PPG has one as well they are not rust converters though they are metal conditioners! they will not eat heavy rust! and are not to be used over existing paint!

when I say "seal" I mean to use Epoxy.
BUT seriously don't use a rust converter on that your asking for trouble if you do.
I bet you could wipe it with some vinegar and most will wipe away be sure to wipe away the vinegar with water then just wire wheel it or sand it then brush some epoxy on it call it good. its very minor.

Doright wrote:

JarFar wrote:Thanks DoRight. So when you say Phosphoric Acid is this like rust converter products?

I was going to do something like what you suggested - use a wire wheel tool in drill to remove as much of rust as possible then coat it with a paintable rust inhibitor then paint it. would that be the best option?

When you said "seal it" - what exactly do you mean please? Seal it with what product?

Thanks

Not really a rust converter but most of them do use phosphoric acid, You can also buy it strait For really bad pitted rust I use it strait. turns Iron oxide (Rust) into iron phosphate. (Black crust) most rust converters on the market are junk will damage paint and cause adhesion problems Most guys here do not use them I am one of the few, don't be-leave what you read about them on different web sights. All will claim to be paint-able BUT none are guarantied to be used under a paint system! and no paint company will say its ok under their paint system!

Only trust those made to be used under a Paint system! Axalta, Cromax, Dupont, PPG has one as well they are not rust converters though they are metal conditioners! they will not eat heavy rust! and are not to be used over existing paint!

when I say "seal" I mean to use Epoxy.
BUT seriously don't use a rust converter on that your asking for trouble if you do.
I bet you could wipe it with some vinegar and most will wipe away be sure to wipe away the vinegar with water then just wire wheel it or sand it then brush some epoxy on it call it good. its very minor.

Thanks again DoRight - so If I intend to paint over this, avoid rust eater\converters. Just remove what rust I can and use an epoxy sealing primer to stop rust getting worse. Then paint with solid color. Does that sound best under circumstances?

NFT5 wrote:Agree. It's not that serious. Just clean up as best as possible and then seal with an epoxy undercoat/primer. This will stop moisture getting back on the metal and is much better than any "rust inhibitors".

Interesting observation here, and I've seen it before. Apart from the fact that manufacturers are less than generous with paint on the inside, I see that this seems to be more on areas which are the inside of exterior panels. It seems to happen less where there is another panel inside of the external one. So what's happening is that when the outside gets cold condensation forms on the underside of the external panel, where that underside is not protected in any way from the moisture laden warmer air inside the van. Creating what in building is called a "vapour barrier" will stop this and reduce the likelihood of recurrence. How? Just line the inside with ply and then insulate in the gap.

Thanks NFT5. As you and others advise - remove as much rust as possible, use an epoxy sealing primer, the paint with solid color.

Yeah, so the idea with epoxy is creating a non-permeable barrier that air can't get through. It takes oxygen (air) to "fuel" the creation of rust. No more air, no more rust.....

DarrelK wrote:Yeah, so the idea with epoxy is creating a non-permeable barrier that air can't get through. It takes oxygen (air) to "fuel" the creation of rust. No more air, no more rust.....

Thanks DarrelK. This is all good information. I have a decent home compressor with a LVLP spray gun I am practicing with so hopefully it will turn out okay.

For the inside of the support member - I was going to try and wash out with vinegar then water. Then after roof painting coat inside of support member with Waxoyl to seal the inside too. Would that be correct action?