Fresh Paint = Spider Cracks, Why? HELP!

Hi all,

For all those body work and paint geniuses, I had some trouble with the passenger door this past weekend for some odd reason. Used an Epoxy Primer Sealer over the old paint which was mixed with catalyst and about 10% of reducer to thin it out. Laid the primer, even coats although I may have not let appropriate flashing times between.

Well when I laid the base coat, about 10 minutes later after cleaning the gun I started to get some spider cracks showing through the base coat (color). Slowly but surely more and more showed up, mostly in the jams and on edges.

So, anyone ever experienced this problem before? Resolution? I'm thinking either my base or primer coats might have been too thick without sufficient flashing? It was about 90 deg outside with a high humidity. HELP?

 

[924dr4x4]

did you wash the truck really good and sand it down between primers to work blemishes out?last time i painted i sanded down the paint,primered the car,washed it,let it sit for 30min,sanded it and primered it again,then washed it,then painted it and it was fine,i used a 2000 grit sand paper for finishes

 

[IZwack]

Temperature -- did you shoot it in direct sunlight or something?

 

[924dr4x4]

i didnt do mine outside...maybe thats why,i did it in a 3 car garage,i didnt even take notice to the 90 degrees outside and high humidity

 

[924dr4x4]

hey IZ..u coming to rausch creek with us on july 19-20??

 

[Blee1099]

Maybe you need a plasticizer

 

[Rick]

I know there are different reducers for different temperature ranges. Maybe you were using the wrong reducer for the temp you were working in?

 

[roccov12345]

Used a medium reducer for both the base and primer. Shot the primer and base in the garage without direct sunlight in about 90 degrees. I usually wash the panel, sand, wash again, sand, wash again, dry it, go over the whole piece with rubbing alcohol, shoot the primer, wet sand, wash, wet sand, wash, go over the piece again with rubbing alcohol and shoot base. Once the base is laid I'll shoot the clear with no process in between. In this case I didn't even get to the clear. The cracks started right off the bat with the base coat.

I will mention that the epoxy primer sealer I'm using usually drys to a dull finish, this time, for some odd reason, it dried shiny. Any ideas?

 

[roccov12345]

I will eliminate any issues with rubbing alcohol or the process in which I sprayed it since this has been business as usual with the entire truck up to this point. Figures too because this is actually the last MAJOR piece of the truck to be sprayed. I'm really thinking it had something to do with the primer/sealer. Like I said above the finish was shiny and somewhat tacky to the touch although it was rock solid dry.

 

[924dr4x4]

you dont have any silicone products layin around in the garage do ya??like tire shine..armor all or anything??or any kind of carnuba wax,i know silicone and carnuba wax can do it also

 

[roccov12345]

you dont have any silicone products layin around in the garage do ya??like tire shine..armor all or anything??or any kind of carnuba wax,i know silicone and carnuba wax can do it also

I do actually have some of that stuff sitting around but nothing open or exposed. Maybe I'll tuck them away in the cabinet for safety measures.....

 

[iammattchew]

Sounds like something is drying too quickly.

I've used Dupont Fish Eye reducer which has silicone in it and a lot people hate it. I've never had any problems with it. Silicone is supposedly highly contaminate-ive.

Did you use any hardener?

 

[roccov12345]

Sounds like something is drying too quickly.

I've used Dupont Fish Eye reducer which has silicone in it and a lot people hate it. I've never had any problems with it. Silicone is supposedly highly contaminate-ive.

Did you use any hardener?

well the only activator/hardener I had to use up to that point was the catalyst for the primer. Maybe my mix was incorrect, although I'm almost positive it was accurate. Here were the mixes:

Epoxy Primer/Sealer mixed 2:1 with catalyst and 10% medium base reducer.
Base Coat (PPG - Omni) 1:1 Medium base reducer.

The only real thing I noticed differently about the primer than anytime prior was the fact that it was shiny when dry as compared to dull. I'm really leaning to the mix of heavy primer coats with inadequate flashing time although I can't be sure........

Here was a write up I found online....Thoughts?


CRACKING
(Checking, Crazing, Spitting, Alligatoring, Crowsfeet)

Cracks or lines of various lengths and widths in the topcoat finish often resembling the cracking of dried mud.

CAUSE

1. Excessive film thickness of the undercoat and/or topcoat.
2. Refinishing over a previously crazed/cracked surface.
3. Insufficient flash time between coats and/or force drying undercoats using air from the spray gun.
4. Mixing incorrectly or using too much hardener.
5. Paint ingredients not thoroughly stirred or agitated.
6. Breakdown of finish due to prolonged exposure to sunlight, moisture, and extreme temperature changes.
7. Using generic reducers and/or hardeners.

REPAIR

1. Remove all cracked paint film and refinish.

PREVENTION

1. Apply all materials following label direction.
2. Completely remove crazed/cracked finishes before refinishing.
3. Do not force dry undercoats by fanning with spray gun air.
4. Mix ingredients thoroughly using the recommended additives. Add each component in proper sequence following the recommended mixing ratio.
5. Stir or agitate materials thoroughly before use to ensure all ingredients are in solution.
6. Use premium two component undercoat and topcoat system to provide maximum gloss and durability.
7. Use the recommended thinner/reducer and hardener, and then measure accurately.

 

[Rick]

3. Insufficient flash time between coats and/or force drying undercoats using air from the spray gun.

From what you've said it sounds like that one fits your situation.

 

[roccov12345]

From what you've said it sounds like that one fits your situation.

I think that may of been the issue, if anyone else has similar problems when using a primer, the problem most likely lies in too thick of primer coats matched with an insufficient flash time between each coat. Sprayed the door over last Friday and it came out great.....

Thanks all!

 

[Tr250airs]

Primer and paint issues

I was reading your problems with the primer and crackling. I just lived through this myself over the weekend and hence my search for answers. I experienced the very same problems you did.

I think I didn't allow enough time between coats. The crackling even appeared where it wasn't visible before on the top coat of color. Was I unimpressed with that. I had sanded out all of the crackling and reapplied primer, sanded again with no crackling visible. I then applied the enamal top coat and wo crackling appeared everywhere. It looks terrible.

It looks like I need to give it time to cure and sand as much of it out as possible. I am thinking of trying a different primer product.

Any other advice would be appreciated.

 

[rlfknlorangers]

these guys are right too many coats of any material layed to quickly and thickly on each other the solvents have no where to go the paint lifts or cracks apart when the solvents come out of it.

more flash time next time and your fine to go once that material has been stripped off.