Hammerite paint under car body

Technical Area Body, Interior & Styling
2

Hi All

Got to look under my Mazda Mk1 and there was quite a lot of rust on the box section both sides where the under sides was badly scraped at some point.

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This I have cleaned up with a grinder, the first side I painted with black hammerite paint.

The other side I still have to do.

However now I’m worried that hammerite may not be the best paint to use as I’ve read that it will crack on cars, because of the way the metal moves.

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Any one else used hammerite under the car successfully?

 

Thanks

MArk

3

 From my limited knowledge, you should not be using hammerite on the underside of the car if you intend keeping it for any significant time.  Hammerite is too brittle and inflexible.  Better to use a zinc based primer and follow that with a bitumen based paint.  

There are plenty of proprietary paints available.  Just read the blurb on the can.   If it is by a reputable manufacturer, it should live up to what it says there.

Gordon T (Central Scotland)

4

 Thanks for your reply:<o:p></o:p>

I have now removed 99% of the hammerite from under my car, <o:p></o:p>

And now have both sides clear of rust.<o:p></o:p>

Had to remove the under seal where I used the grinder,<o:p></o:p>

Went to Helfords but couldn’t see any zinc based primers!<o:p></o:p>

Any ideas where they are sold, also what would I replace the under seal with?<o:p></o:p>

I do have some “underbody seal with added waxoyl” But this stuff stays tacky, would like something that dries really.<o:p></o:p>

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Thanks<o:p></o:p>

MArk

5

 hi mark,  i wax oil first, then if ya want underbodyseal, flexibility is the key, if it hardens (such as paint) any damage/chips leaves a water trap and rust!! this does not happen with wax oil as stays flexible/tacky, the under body seal does flake after a while so re application is required every 12 mths or so hpe this helps goochie

6

 Thanks.

In the end I found some Zinc 182 and some Comma rubberised formulastion underbody seal

from CTC Witney.

So hope that that combination will do.

 

Thanks

 

MArk