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i used rustoleum primer, automotive touch paint and clear coat.

paint job was pretty good after a week or two, these scratches began to show up..

wtf happened

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before the scratches appeared, gonna finish up with scratches and all

1/16 mercedes 540k entex kit i think. 60$ shipped sometime july aug.   recently saw on ebay for over 200$  

kit is a complete headache, body wise nothing fits, good buy at 60 bucks though.

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Others will know better than I but, You had a bad chemical reaction between the primer and paint. You got a form of Crazing going on. Not sure what happened after that, however.

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As alexis pointed out, the use of dissimilar paints can lead to many unintended problems. Many builders have figured out how to use paints from many different sources and often not designed to even be used on plastic surfaces and still get remarkable results. My suggestion would be to try and stay with one product line from primer to clear coat and be sure that each layer of paint is completely dry before the next coat. 

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I had the same problem! Used all Tamiya primers and paints, all purchased around the same time, all painted in the same conditions. I've used the same paints and primers (literally the same cans)on other projects with no issues at all.

 

 

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That is paint shrinkage. The color coat didn't bond to the primer properly. You'll have to see what kind of paint the color is and pick a more appropriate primer for it.

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Difficult to diagnose with photographs - I agree with all of the above.  it appears the primer was not fully dry before the top coats were applied and the top coats dried first.

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Those aren't scratches they are cracks. As said a result of mixing paint brands. A lot of times there will be instructions for when you can recoat. However different manufacturers use different solvents which can react with each other. 

How long had you waited to let the primer dry?

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In the 1:1 automotive world they use a "system" when painting where all of the products are from the same manufacturer that are coordinated in their chemical composition to work together as a syste.  All lacquers, or enamels are not the same despite them being lacquer or enamel.  I always test my paints for comparability using spoons or scrap parts first.  Rather to have a paint job go bad of a plastic spoon, or old/spare plastic part then on the actual model.

 

A.J.

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1 hour ago, bobthehobbyguy said:

Those aren't scratches they are cracks. 

How long had you waited to let the primer dry?

+1 on cracks. Also +1 on suspecting insufficient drying time on one or more layers involved. :unsure:

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3 hours ago, Snake45 said:

+1 on cracks. Also +1 on suspecting insufficient drying time on one or more layers involved. :unsure:

 

3 hours ago, Snake45 said:

+1 on cracks. Also +1 on suspecting insufficient drying time on one or more layers involved. :unsure:

Yup.

The problem appears to originate in the colour being topcoated before it was ready. The primer may have been too green for colour as well, but the shrinkage pictured is a colour coat issue.

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I agree with the consensus that the primer was too soft for the paint. Primer is the stable foundation for the paint to build on. Kind of like building a skyscraper on sand. If it's not solid, it won't support the top coats afterwards. 

Good thing is, it doesn't look like the plastic is crazed so you can strip it off and start over. Try using brake fluid to soften the primer and the paint will come off with it.

Next time, let the primer completely harden before putting paint on it. You should block sand primer smooth before adding color anyway. If the primer sands easily with powder coming off, then it's ready. If it doesn't and it gums up the sandpaper, then it's still soft and needs more time to harden.

Edited by Oldcarfan27
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I believe its the fact that your primer wasn't cured before you top coated.  I had the same thing happen on a monte carlo that I had painted two tone. Both colors were duplicolor and both cracked. But I had tried to do the hole paint job in like two days. Stripped it and the second time around I let everything stand for at least three days before applying next color. Then it came out great.

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8 hours ago, Fat Brian said:

That is paint shrinkage. The color coat didn't bond to the primer properly. You'll have to see what kind of paint the color is and pick a more appropriate primer for it.

yep I think it was a too heavy colour coat followed by too soon a clear coat

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The Rustoleum primer is probably enamel & the color coat is likely a lacquer or urethane.   You should never shoot anything but enamel over enamel.   Find a primer from the same manufacturer as the paint.

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1 hour ago, jas1957 said:

The Rustoleum primer is probably enamel & the color coat is likely a lacquer or urethane.   You should never shoot anything but enamel over enamel.   Find a primer from the same manufacturer as the paint.

I agree, Rustoleum is BLAH_BLAH_BLAH_BLAH enamel. A good  lacquer primer would not do that under another lacquer

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Just want to remind everyone that the site has rules about language. Do not curse here, do not change the letters around or use symbols to get past the filter and do not use acronyms. This is a family friendly site.

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When using lacquer paints, I always wait 1 week between paints. Prime, wait a week and shoot color; wait anothr week and shoot the clear coat. That should be enough time to let the previous coat cure and shrink.

 

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  • 2 weeks later...

Agreed with all of the others. Paint and primer did not like each other. I have never liked Rust-Oleum products. Dry times are off the charts. With automotive paint, you have to use an automotive primer that is compatible. In my opinion, Rust-Oleum is not. I have had great results with Krylon industrial grey primer for years. I have covered it with everything from enamels to lacquers, to eurothanes. As a matter of fact, I just used that very same paint mfg (Automotive Touchup) over Krylon Industrial grey primer on my Chevelle build. Turned out great. I do not like the nozzles on the Automotive Touchup cans though. They drip due to too wide of spray pattern. Spray hits the rim edge of the can. Other than that, very nice paint and clear. Bottom line, get rid of the Rust-Oleum primer. IMHO Looks like a trip to the purple power tank is in your future unfortunately. I feel for ya, I’ve been there. Had that happen on a Ducati Monster tank I painted. Had to sand it all back down to bare metal. Very sad day. 

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