20 replies to this topic

[germini30]

Resprayed my mini using cellulose and its cracking. I keyed the old paint with 400grit then bar coated it. After that I applied several thin coats of 1k high build primer. I left it a couple of weeks before wet flatting and paint. It looked great at the time but now the top coat has got little cracks here and there. Mostly around edges but some have appeared in funny places. Am I best to blow over these areas or should I get an orbital sander and go back to the metal?

[corrado vr6]

Would it be where you may have sanded through when flating the primer?
did you use anything out of a rattle can that maybe reacting ie: etch primer?

Or it could be moisture in your primer from being left that time before topcoat

Edited by corrado vr6, 01 March 2015 - 10:03 PM.

[germini30]

No nothing. All cellulose through the gun

[Rocket.]

Did you use panel wipe/tack cloth before top coat ?

[germini30]

Yes I did

[Stu.]

If its around the perimeter and on radius areas it might be shrinkage cracking of the topcoat. What thinners mix did you use ? Might help if you could post up some pics.

[germini30]

5-6 coats at 50:50 then a couple of coats at 75 thinners to 25 paint

[germini30]

Just scraped the top coat off where its cracked.the cracks are even in the primer.i think there is too many coats of paint on the car. Stripped some paint back with a polycarbide wheel and there is about three to four layers of paint. How is best to go back to bare metal.

[Daz1968]

It may even be compatibility between paints or lack of adhesion. Really need some pics to make a fair judgement.

[germini30]

I think its too many different types of paint. There is 2k and that was overpainted with water based and the cellulose paint is too much even with the bar coat. Cracks are appearing all over it now

[Daz1968]

Yes sounds like best bet is to remove the lot and apply an epoxy or etch primer and start again, not what you want to hear though, epoxy is very good and gives a good build and is easy to sand dry so this is what I would use if you haven't got airfed.

[germini30]

Is upol 1k etch suitable for use under the celluloseprimer and paint

[germini30]

Whats best. Sand. Paint stripper or heat gun.

[Daz1968]

Upol 1k etch is ok but I prefer epoxy. Not sure of best way to strip as I have to do same to my mk2 shortly but was planning on trying some strip and clean discs on my angle grinder first.

[germini30]

I used a polycarbide disc earlier. Seem aggressive to be honest. Would a da with coarse discs be best. What grit would be best?