Water Stains/Acid Rain Eating into new 2K Paint???

[jamesm80]

Hi,

I have a spoiler for the rear end of my car that i decided to have a go at painting, and overall, the finish i am very happy with. It is grey metallic with a clear coat on the top.

Being advised that 2K paint is the best, i checked it out and found a company (CHROMADEX) that sold ISO-FREE 2K (since i was told that normal 2K is a killer).

I mixed everything accurately, painted the spoiler, and left it in the warm for 7 days (for full properties) as indicated by the tech data sheet. After that, i put it on the car.

It had been raining a little, and within a couple of days i went out to the car to dry it off, and found that under some of the large "pools" of water, the paint had discoloured and become dull. I tried T-CUT and polish to no avail, but then also discovered that these discolourations had "etched" themselves into the lacquer. There were lots of them, even etchings that had not caused discolouration (but were visible in certain lights close up).

I ended up having to use a very fine wet 'n dry paper with water to sand out the etchings, and repolished. I immediately waxed the spoiler and then added an auto-glym sealer in the hope that the problem would not return. I checked every day since (drying it off) and the spoiler mostly had a damp haze each time which didn't cause a problem, but on about day 4 it had rained hard and left large pools... the problem then returned.

I've spoken to a distant family member who paints cars for a living and they seem confident that the problem "is the paint", he is sending me down some "DuPont" which again he is confident can be used, left in the warm for 48 hours and put on the car straight away.

Basically i'd like your views on this but also i'd like to know, should a 2K paint job be so sensitive to rain like this?

[TuT]

yes the paint is suspect. Is your relative sending you Dupont Chromabase?
Ahhh, it doesn't matter for this discussion.
I am not familiar with the material you originaly used, but if I were redoing this in my shop I would remove the suspect material as best I could, prime with a sandable primer, block sand, then spray with a primer/sealer before base/clear.
I know it expensive and alot of work, but it's the right way.
The minimum you may get away with is scuffing the piece with 400 to 600 grit leaving no shine behind, however try not to break through the clearcoat. Then use a quality non reduced primer/sealer. At this point check the piece over really good to be sure you don't have any scratch swelling (or else it will show up like 280 scratches in your silver base) if you do I'm sure you will have to prime. If not go ahead and use the base putting on your first 2 coats medium not full wet and be sure to give plenty of flash time between coats for the reducer you are using.
I hope this is timely and helpfull.