Potential Paint Problem (or disaster?)

[adritch]

I have recently wire brushed the entire underside and boot, then zinc primed, then applied a layer of red oxide.

Then yesterday I painted Hammerite over the red oxide (hopefully some of you will now be thinking 'you don't want to do that') in the boot and the rear underside up to the front spring hangers.

Stood back to admire my work and then got a bit of a shock when I noticed how the paint was crazing. Then looked at the red oxide which said 'suitable for over painting with any white spirit based paint'. Hammerite being a solvent based paint explaining the issue.

So, question is, will it ever cure and it'll just look cruddy (in which case that's fine as it's not anywhere special. Or do I have to strip the whole lot off and do it all again?

Any advice (especially if I can get away without having to re-do it all) will be greatly appreciated.

Thanks,
Adam.

[chickenjohn]

I've never painted over red-oxide, but I do know that hammerite paints OK over zinc primers. So I'd strip back to bare metal (I'm afraid!) and paint with zinc primer, then hammerite.

Or, you could possibly use a stone chip coating or underseal (which is often white spirit based) over the red oxide.

Personally, I don't like underseal.

[rayofleamington]

There are quite a few paints that don't like going on top of red oxide, and if it has gone 'crazed' don't expect that it will be any good by waiting longer

[Willie]

Just one question. Which type of Hammerite did you use?? I ask
because the earlier types of this paint were SUPPOSED to dry to
a crazed finish. The smooth type didn't appear until much later.
Have you checked the tin?

[guydenning]

mmm - has it crazed or has it gone all dimply? I've never had problems putting hammerite over anything before (nothing would go over hammerite - but never the other way around). Not that I have a huge cv of spraying stuff in hammerite mind...

[bigginger]

Isn't Hammerite supposed to go onto bare metal or Hammerite primer? From the smell of the thinners, there's Acetone involved somewhere, so it'll dissolve pretty much anything underneath, so I'd worry about Zinc primer too.
a

[guydenning]

stop being coy about hammerite big-g. i just know you've got tins of the stuff on every shelf.

[bigginger]

Too true, but I don't think you'll get a concours finish putting on over anything except what it says on the tin. My inclination would be to just whack on another coat and see if it looks better - but maybe that's just me - and you too, I'd say...

[adritch]

I'm inclined to go along with you there Andrew, but when I left it on Saturday after 6 hours or so it was still a gooey mess. Unfortunately it's in my (very patient, it'll take me a couple of weekends honest guv) friends garage an hour away so won't get to see it again till next weekend to see if it has finally gone off.

It is Hamerite smooth, so it's definately some sort of reaction. My concern is that it looked as though it was actually lifting the red oxide off the metal, which can't be good. Having seen the problem I also painted one area directly onto the zinc pricmer and this seemed to take ok.

I think I'll probably have to take the whole lot back to metal and start again. Still, at least I haven't done the whole underside or then I really would throw my toys out the pram. As for the rest of it, I guess I'll get some standard black gloss and paint that onto the red oxide and then Waxoyl over the whole lot when done.

Deap joy, I love spending the day scrabbling around underneath the car, beats a workout any day for aching muscles!!

Thanks for the comments,
Adam.

[bigginger]

Sounds wise to me. You get used to finding that a day of foul, dirty work was a waste of time, don't you...