Treating surface rust for dummies.

[Partridge]

The ammount of grot on my car is not the end of the world, but I want to kill it before it takes hold and becomes a problem. For the time being, I've smeared some Vaseline over it to try and seal it off. Obviously, this is a sticking plaster and won't solve anything.

 

I've uploaded these before, but have them again.

The metal itself is solid.

 

This is a touch worse.

 

There is also some nasty blistering coming on the front skuttle pannel, which I will upload pictures of later today.

 

Any guidance or help appreciated!

[sierraman]

Similar problem to our Focus. Wouldn't advise commencing this sort of work until late spring at earliest. Only way to do it properly is take back to bare metal, then work in the rust convertor, kurust or whatever, then fill as appropriate, on the inside lip of the arches, I'd be tempted to paint on some zinc primer, 2-3 coats, applying some fresh paint over that possibly if its very localised by hand. Trouble with aerosol is that its prone to chipping easily and hence rust. Again you want dry weather for this kind of work...

 

The last picture might be worth applying some Shutz on if the metal underneath is completely sound.

[TRW]

Vactan is da bollocks for this. Its a rust convertor and primer in one.

 

Although a coat of Zinc 182 woudn't go amiss on a vulnerable area like those wheelarches, combinded with what Sierraman says about Schutz on the inside of the arch.

[sierraman]

I've conducted a few tests of my own with Zinc 182. It does well if the surface has been taken back to bare metal, where its just roughly sanded down and applied rust can creep back through. Kurust is what I've used recently for these types of job however I've found Loctite Rust Remedy more effective. You used to be able to get some stuff called Brunox which was ace but its long since out of production.

[Partridge]

Thanks guys. I'm looking into Zinc primer right now.

[alf892]

You would be surprised how rust reaches out under paint........so make sure you go far enough out from the visible stuff. On wheel arch lips be careful to get some paint on the actual edge of the metal.......otherwise it comes back real fast.

 

A .painter once told me there is nothing like welding and amateur body repairs (in winter or damp) to make a motor rot

[xtriple]

I've always thought that welded repairs where you cant get to the back to dress back and properly paint just rusts like fury. I was taught that welds HAVE to be covered within 30 minutes as the rust starts/gets hold.

 

I have welded loads of chod over the years and it always gets worse quickly. But, when my son had his Nova, it needed one bit of welding on the front panel (MOT man was being a cock but passed it on everything else so let him off!) and I made a correctly shaped bit, cut out the old, welded and then ground back BOTH sides (you could see it through the wheel arch) and prepped/painted both sides properly and it never rusted at all. That little car was a right minter thinking about it - he should have kept it!

 

I always think welded repairs signal the death knell for a motor. If possible replace with new completely or, if possible, take the piece off so you can get to both sides and do the job properly. I HATE rust with a passion!

[Partridge]

I HATE rust too. We're probably in the wrong place.

[xtriple]

The only reason I like fibreglass cars is..... go on, guess! But they have their own set of problems....

 

I will pay extragant amounts of dosh for a car with NO rust even if the engine is in bits in the boot!

[Partridge]

Well lets face it, engines are easier to find and fit than new bodies...

[xtriple]

Well lets face it, engines are easier to find and fit than new bodies...

That's what my Grandad always said.

[twosmoke300]

Por15 seems to slow rust right down

[mat_the_cat]

Heard a lot of good stuff about POR15, although I haven't had much luck - 2 coats on a sandblasted towbar, stored in a garage for 10 years (never saw rain) and it came back through. That may be bad luck/poor prep, I dunno as I haven't heard of any other problems.

 

I prefer to use a rust *remover* rather than converter, as with a converter the danger is that the top layer converts, leaving unconverted rust underneath. At least if you get back to shiny steel you know where you are.

 

Also bear in mind that there is zinc primer and proper cold galvanising paint like Zinga and Galvafroid. Feel the weight of a tin for comparison! Something like 95% zinc IIRC, so has similar protection to proper galvanising - the downside is it's relatively soft so best to cover with other paints. It's a bugger to sand too, as it's so full of metal it just tends to smear.

[Morgan84]

Keep the areas covered until the warmer weather as already mentioned, and then have a sand back, zinc prime, and then build up to the final top coats. Petroleum Jelly, or plain grease are good for sealing the nasty's in away from the winter salt and wet 

[SambaS]

I was wondering about the surface rust on my MG ZR's door corners...

 

 

So I cut them off

 

 

 

Total overkill of course, but Id replaced the door already with a spare

 

 

 

 

 

 

 

The filling work required as next stage is an art in itself, as would have been the paintwork!

[mat_the_cat]

Here's a before and after picture of what can be achieved chemically. Fair enough, the bottom of the channel and inner lip were too thin and I had to weld new metal in, but the section which joins the rear wing was savable. A grinder wouldn't have got into the pits, and a wire brush knot wheel just isn't harsh enough on pitted rust like this to completely remove it in my experience.

 

 

[sierraman]

What did you use?

[Partridge]

Here's a before and after picture of what can be achieved chemically. Fair enough, the bottom of the channel and inner lip were too thin and I had to weld new metal in, but the section which joins the rear wing was savable.

That's my worry. I'll end up scrubbing and spraying stuff on there until I no wheelarch lip at all.

 

With the advice from this thread in mind I think all I will do is keep sealing it until the better weather comes, then decide if I'll tackle it myself or pay somebody to do it.

[mat_the_cat]

What did you use?

 

That was Deox gel (Bilt Hamber)...it turns the rust to a dark brown water soluble substance, which you wash off afterwards. It may need a wire brushing to remove it from the pits, but I've been impressed with the way it works. Once the gel has turned yellow, it is spent so if there is still rust present then, you need another application.

[dollywobbler]

Zinc 182 is just one tool in the battle against corrosion. Slapping it over existing rot will slow it down (I've been experimenting with the 2CV's front wings, which are ultimately going to be scrap anyway) but it only takes a few months for corrosion to come back through. Similarly, even the parts where I used rust converter are still trying to rust, even with zinc 182 applied afterwards. The best way to do it really is to get rid of as much rust as possible by mechanical means. That inevitably means discovering more rot, and possibly holes too. I got lucky on the XM. The rear wheelarches were all bubbling up but actually, the galvanising was preventing corrosion - it was just water building up beneath the paint. Gently rubbed them back to get the paint off and it's all solid. Can't get that job finished until better weather arrives though, so it's zinc 182 just slapped over the metal for now. I still had to use a hairdryer to help it go off.

[nisfan]

when applying primer eg zinc182 should you not put a top coat on as the primer is porous? (when the car is out in the elements)

[forddeliveryboy]

[Tamworthbay]

I would love to see that posted under the title 'which polish?' On a detailing forum.

[RayMK]

I've used various rust converters over the years, but not had huge success despite careful, thorough preparation and following with Zinc182 and a topcoat.  Clearly, my idea of thorough is not good enough.  I have found that Hammerite and underseal tend to hide problems rather than arrest the corrosion.  Bondaprimer, an epoxy based primer and undercoat that looked like red lead is the best product I've used.  I thought it was no longer available, but a quick look on the net indicates that marine stockists have it.  I used it on my Reliant's chassis then top coated with chassis black when I bought the car in 1992 and it's still in very good condition now.  This is why anecdotal evidence can be so misleading.  The chassis was in very good order when I bought the car despite its 1961 vintage.  It is also heavier gauge steel than in any monocoque body, and in my ownership the car has only done 3,000 miles and always been garaged.  My Stellar's slightly rusty rear wheel arches laughed off a professional repair in a bodyshop after just two years.  I was disappointed.  I attacked the rust myself last year using converter, zinc 182 top coat and lacquer but within 6 months rust was bubbling and staining again. 

 

I've previously shied away from using Deox, purely because it seemed odd to have to wash the bare metal with water afterwards.  Maybe I should give it a go since my other efforts have been fairly hopeless.

[Tamworthbay]

Detox c is brilliant, the powder is better than the gel but limited to bits you can fit in a container.

[mat_the_cat]

 I think the reason the liquid (from powder) is better than a gel is that the gel gets depleted locally where the surface of the rust is, and fresh gel doesn't reach the rust quickly enough to react. That and it's easier to keep the liquid warm, i.e. on a plate warmer.

 

I too felt strange washing it off with water, but it seems it must leave a film behind or possibly passivate the surface, as I've seen no problems with rust forming immediately afterwards, even when leaving for a day or so no flash rust has formed.

 

Some more anecdotal evidence on a coating method here and the interim follow up in post 83...

[Royale80]

I've used Bilt Hamber hydrate 80 to kill any surface rust after using a flappy disc. I've then painted it (by hand!) with Lechler epoxy primer-a 2k mix. Found this works really well.

 

Steve

[mat_the_cat]

Have you taken it back to (mainly) shiny steel with the flap disc? How long has it lasted so far?

 

I've used Hydrate 80 on wire brushed rusty steel before, overcoated with UB wax. No bubbling so far but only 18 months...

[Danblez]

I have been using hydrate80 on my focus door bottoms for years. Even if you don't cover it, which you should, it lasts about 12 months.