PPG DP-50 Not Curing

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340swinger4spd

340swinger4spd

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Hello, I am in the process of painting a hood for my Dart. I had it bad blasted then cleaned with Acetone. I sprayed DP-50/ 402 activator mixing it exactly as the label says. I then did 2 coats of K-36 high build primer. Then blocked it out. I then sprayed DP-50 again but reduced with DT-870. Normally it would be ready for color in about 20 min. Last week I applied my Omni MTK single stage and after 4 days it still wasn't cured. So I sanded it all off and redid it thinking I did something wrong. Tonight the same issue came up. I applied the DP-50 again as a dealer and after 8 hours it gummed up my sand paper (I had a few dirt specs in the sealer) so off it came again. Is it normal to wipe off epoxy paint with acetone on a rag? I thought it would have a better cure then that. Any ideas why this primer won't cure? Any help will be greatly appreciated.
 
DP is designed to not be sanded. It will gum up sandpaper slightly. I have used it for years and never had any problems. It does not set up and harden like the K series.
 
What about wiping the primer off with acetone and a rag? It wiped squeaky clean instantly. Is that normal? I mean I know acetone would cut the primer but I didn't think it would dissolve the primer so quickly.
 
Epoxy primer cures slowly. Dp has a 72 hour pot life and will always sand like bubble gum. I'm not sure why you're applying it and wiping it off all the time? Also your original post said you sprayed single stage over it and that wasn't cured after 4 days?? Why would this be the fault of the DP?
 
Round 3... New printer base and activator. And just to be sure triple checked the ratios....
20180504_233505.jpg
 
67Dart440GT said:
Epoxy primer cures slowly. Dp has a 72 hour pot life and will always sand like bubble gum. I'm not sure why you're applying it and wiping it off all the time? Also your original post said you sprayed single stage over it and that wasn't cured after 4 days?? Why would this be the fault of the DP?
Click to expand...
I'm not wiping it off all the time. But when I have to start over, I want smooth bare metal. That way I have less blocking to do.

I suspect that the epoxy (used as a sealer) did not cure right. It was sticky under the single stage. If that is true, that would explain why the single stage did not cure. Of course the single stage could have softened the sealer to.

I have been painting cars for years and have used these exact products with great results. This is the first time I've had an issue like this.
 
FYI, I have been using a water base paint panel prep to clean prior to paint instead of the old solvent based PrepAll type. It cleans very well drys a little slower. Seems to be alcohol based. Sanding residue cleans off very nice. Wont attack primed surfaces like acetone might.
 
Before I shoot I have always used wax/grease remover. The acetone was not normally used. But since I needed to remove the primer I was surprised how easily acetone cut it.

That's a good idea though. I will use that when I paint my Challenger.
 
340swinger4spd said:
Hello, I am in the process of painting a hood for my Dart. I had it bad blasted then cleaned with Acetone. I sprayed DP-50/ 402 activator mixing it exactly as the label says. I then did 2 coats of K-36 high build primer. Then blocked it out. I then sprayed DP-50 again but reduced with DT-870. Normally it would be ready for color in about 20 min. Last week I applied my Omni MTK single stage and after 4 days it still wasn't cured. So I sanded it all off and redid it thinking I did something wrong. Tonight the same issue came up. I applied the DP-50 again as a dealer and after 8 hours it gummed up my sand paper (I had a few dirt specs in the sealer) so off it came again. Is it normal to wipe off epoxy paint with acetone on a rag? I thought it would have a better cure than that. Any ideas why this primer won't cure? Any help will be greatly appreciated.
Click to expand...
We just had a very similar problem with the DP50, do you have the batch numbers?
 
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