Cracks in paint

I try to paint the Revell S600 with Tamiya TS-14 black paint but end always with 'cracks'. I primed the body first with Tamiya white primer and sanded it with tamiya 1200 grit sandpaper. I wait 10 minutes between each layer, the third layer I put on thick. But the cracks :mad: keep coming back after 25 minutes..... Does anyone had the same problem??

Greetings

http://files.automotiveforums.com/uploads/169757Cracks.jpg

Been there done that........ lots of times!! :bloated:

I always get it when I use a brand of primer thats not plastic friendly, like auto primer. I have used several brands of primer and the one Im using right now seems to work best for me. Its Krylon Primer for wood,plastic, metal all around primer. It dries in about 12 minutes!

My guess is that since you used Tamiya brand primer that maybe it was some oil left on the body and reacted with the primer to form those cracks. Also laying on too thick of a coat of primer will either make the primer bleed down your car or form cracks where you might not have seen any if the coat was thin. But thats MHO and my :2cents:

Take or leave it...

Scott

How long did you let the final coat of primer dry for?

The cracks were not visible in the primer, but were visible after paint, right?

I washed the body in water with some detergent before priming. The coat of primer was very smooth, no cracks or bleedings. I let it dry for 2 days. The cracks began to show up after painting (first two light coats, the third heavy). The paint seemed good at first but after 20 minutes or so the 'cracks' began to show up... Maybe I should let the primer dry for a week??

i think theres something wrong with your paint,not the primer i belive,coz i painted my NSX only a few hours after applying the primer and there were no cracks.

i play it safe and wait 4-5 days. (but then again this is my first well done model i am working)

-PS- no cracks on the well done comment by saying you take yours medium rare... sounds stupid but i know someone would have said it.

I have had this happen as well, my theory is that I sanded the primer too much. You need to leave it slightly rough for the paint to stick well.
Just a theory, maybe I inhaledt oo many paint fumes:bloated:

I have had this problem with Krylon primer. It's usally tto much paint to quickly applied especially in more humid weather. It is some times actual crazing of the plastic and should be stripped and the plastic sanded. apply the primer in very light coats at first then alittle heavier and allow plenty of drying time. I am surprised it happened with Tamiya primer. You really should use grey primer under black anyway.

I'll paint it over and try gray primer and 800-1000 grit sandpaper. I let you know how it works out.

Thanks for the replies!