Problems with paint shrinkage on a repainted panel

[wxl1988]

Here's a question for those who are knowledgable with automotive paint.



About a year and a half ago, the trunk on my 2001 BMW M5 was repainted. Since then, it has been stripped and repainted seven times (the most resent was a month ago) because the paint kept shrinking. The first six times, it was painted at shop "A," and the last time at shop "B."



Both shops do phenomenal work, located in Los Angeles County, and they both use Glasurit paint.



Since both shop A and B and more than capable enough to do the work, why does the paint keep shrinking and losing gloss? Shop A told me it had something to do with the color of my car (Lemans Blue) and because of the switch to water based paint. Shop B told me it was because of the switch to water based paint.



Here are some pictures (sorry for the poor photos, it's hard to get a shot of the problem)



Reflection on the trunk is nice and dull

Wetsanding and polishing does not work because it is underneath the clearcoat.



Any comments are much appreciated! Thanks in advance.

 

[Apollo_Auto]

It has nothing to do with the color of your car. This is what happens when too many layers of paint are applied before the previous layers have properly cured. Let's compare this to car wax: You apply a layer of wax to a car and then remove it. 10 minutes later you apply another layer but when you remove the second layer, it looks like hell. That's because the 1st layer has not properly cured yet (here the time is irrelevant , as it's just an example) and you're smearing the 2 "uncured" layers together.

 

[David Fermani]

Definately not a color issue what so ever. There's tons of problems right now with shops applying a solvent clear over a waterborne base. That's my guess from a lack of pictures showing what's actually going on. Glasurit doens't offer a waterborne clear.

 

[wxl1988]

Thanks for the comment, guys. I know the pictures don't really show. To better describe it, the paint is losing gloss underneath the clearcoat. E.g. if you're parked at a gas station and look at the reflection of the halogen lights, the reflection is fuzzy.



To my understanding, California VOC laws do not allow solvents to be used in bodyshops. Everything is waterbased, unless you 'cheat.' So I don't think solvent based on water based is the issue here.



I'll have the shop try again with extra attention to prepping, painting, and curing (not like they didn't before), and see where I get. If all else fails, I guess I'd have to solvent for the paint job.

 

[David Fermani]

To my understanding, California VOC laws do not allow solvents to be used in bodyshops. Everything is waterbased, unless you 'cheat.' So I don't think solvent based on water based is the issue here.



I'll have the shop try again with extra attention to prepping, painting, and curing (not like they didn't before), and see where I get. If all else fails, I guess I'd have to solvent for the paint job.

Akzo Nobel(Sikkens) is the only major paint manufacturer to offer a waterborne clear in addition to their water'd base. They don't have alot of market share on the national level, but CA is their strongest market.



Body Shops across the nation are experiencing drying problems with the Waterborne technology. Mainly because they are almost forced to apply a solvent clear over the water'd base. This can (especially in your case)cause problems.



I know a shop that did a full paint on a Yellow C5 Vette(3 stage via water) almost 3 times before they had their Dupont Rep come out and assist. After he helped paint it a 4th time, the car still had problems and the paint failed. They ended up going with single stage and putting clear over it (all solvent).