Car body repair; Best way to treat bare steel prior to filler-primer?

There seems to be a lot of conflicting opinions on this, but I'd eppreciate your views on what is the best way to treat bare steel, pror to applying filler-primer, when affecting a bodywork repair on a car, (having removed rust from an area and having abraded it, as far as possible, down to bare, steel).

I know there are various Jenolite-type products, and someone suggested a zinc-based primer. What are your views? My primary concern is to inhibit rust, of course.

I once read the results of an experiment which seemd to conclude that Hemmerite was one of the best rust inhibitors of all, but I don't know how suitable Hammerite would be in this type of application...

Many thanks,

Al

Reply to
AL_n
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Bare steel. It's a primer.

(clean, brush and de-oil it though. If it's already rusty, then phosphoric acid)

For priming under paint, then a zinc-based primer over that. Davids

182 is good.
Reply to
Andy Dingley

That's all you need to do.

Not required before the application of filler, but essential after

Nah....Just Nah

Reply to
Nthkentman

Indeed. Hammerite tends to get air bubbles in it, which then cause pinholes in the finish. Water gets in, gets trapped underneath the paint, and after a while it's as if you never painted it (apart from the flakes of Hammerite-coated rust on the ground, of course).

Theo

Reply to
Theo Markettos

thats what the resin based filler does. You won't find better paint.

The experimenter must have been very drunk

NT

Reply to
NT

A decent acid etch primer. I like Upol.

Hammerite is a con...

Reply to
Dave Plowman (News)

What type of acid? What strength?

NT

Reply to
NT

"Dave Plowman (News)" wrote in news: snipped-for-privacy@davenoise.co.uk:

Thanks for the responses. It's funny, but I've always thought etching primer to be a con. I used to use it when I was doing a lot of refinishing work in a certain factory in the 1980s. I found that after it was cured, you could scratch it off as easily as most other paints and primers. OK, it might roughen the surface of the steel very slightly, on a microscopic level, but any abrasive paper does that far more effectively.

I think (not sure) it was Which Magazine that tested a number of rust inhibitors, many years ago, and found Hammerite to be exceptionally effective. I've found it to be good too, but have never used it of car body repairs as a primer.

Al

Reply to
AL_n

Andy Dingley wrote in news:38fb4cbf-b4e6-489c- snipped-for-privacy@e29g2000vbm.googlegroups.com:

Thanks.. What about red oxide primer? Most people used to swear that was the best primer to inhibit rust. Is zinc-based now considered better?

Al

Reply to
AL_n

It's what most pro body shops use on bare metal these days, I'm told. But as regards adhesion, that would need to be checked very much later, rather than just after it's cured.

I painted a wrought iron fence in sections using Black Hammerite, Smoothrite and ordinary Wicks gloss - all direct to the steel. The Wicks gloss lasted longer - and of course was very much cheaper.

You might also have problems getting car paint to stick to Hammerite - without using a sealer coat. And of course the rough finish it produces is exactly what you don't want for a decent final finish.

Reply to
Dave Plowman (News)

Dare I suggest lead? It was the original car body filler and ISTR even

30 years ago some purists swore by it for old vehicle restorations.

A quick search produced

looking to do a lasting repair.

j
Reply to
djornsk

davenoise.co.uk:

I once took Which seriously too.

NT

Reply to
NT

In article , AL_n writes

I think a few may be mixing up hammerite paint with other hammerite branded products. They do make a rust treatment solution that I have seen but have no experience of, I saw it supplied in concentrate form in a 2l or so container and the instructions required it to be diluted 10:1 with water. It was used to dissolve rust on parts by long term immersion. No idea what the ingredients are but perhaps the usual phosphoric acid base of other similar products.

Reply to
fred

IIRC Hammerite (now) own Jenolite. But seem to be re-branding that to their name.

Reply to
Dave Plowman (News)

Never (ever) found Hammerite to be worth a toss. The best rust inhibitor/primer is Bonda Primer. Not easy to find but Google BondaGlass Voss for details of the maker. I painted my trailer with it over 1o years ago and there is NO rust on it.

For lots of info on car repair look at Frost

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Reply to
RJS

A number of car manufacturers, in conjunction with their preferred paint supplier, specify the complete paint process for bodywork. Etching primers figure in a lot of them - for instance all the vehicles with 'galvanised' bodywork such as Porsche and Audi from the mid 90's required etching primers or the subsequent layers fell off. If I recall correctly the only surface preparation allowed was an extremely fine grade of Scotchbrite and a wipe on wipe off solvent. Normal abrasive paper was off limits and panels were completely replaced rather than part repaired.

Reply to
The Other Mike

It's a long time since I've had to do this, but I used to own a mini some decades ago, so I had plenty of rust repairs to do. ;-)

I used Zinc primer (Davids Zinc 182, since I still have a can of it), on the basis that it was as near to galvanising the steel as I could do. Then on top of that went filler (if I was using any, or for small areas to be filled, I just built up with the Zinc primer, sanding back all except the last coat).

I never had one of these areas rust again. OTOH, I had previously found the red lead oxide paint to be useless as preventing re-rusting, which is why I looked for something else.

No presonal experience, although I've heard it's good to paint on when you haven't managed to get rid of all the rust.

Reply to
Andrew Gabriel

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