Paint Experts What The F%$$ Happened!!!!

Use one product all the way through, DON"T MIX PRODUCTS, companys test their products with their products not some cheap crap. If you use Dupont, PPG or BASF use it all.
Don

 

well went to the paint store today and took the pieces with me!!. i have a rep from pcl stopping by in the morning. ive never had a problem spraying over 600g. that is what i usually finish with. i used prepall by klean strip, never had a problem with it before. was kinda upset at the paint store, the person that helped me that day said they couldn t mix the color in a PPG single stage. today the girl i usually deal with said " sure we can" so what the hell happened there i dont know. everything was right as far as temp and stuff. the original color i sprayed was a lighter blue and it stuck bitchen, owner wanted it darker... i resanded everything today with 400g and after the rep leaves im going to seal it, wait the recommend flash time and lay the paint on. hibbyjr,the epoxy stuck like it should, on the back of the paint you can even see the small sanding scratches from the epoxy that the paint didnt stick too!! after the rep leaves i have to 400g it to respray. thanks for all the input guys... the last thing i thought last nite is i had my cousin working with me at the time and with my luck on this firewall, is he got the paper mixed up and wet sanded it with 1000 grit. im betting that is what happened but it really sucks to take the chance!!

 

Now it is suspiciously starting to sound like the paint store may have mixed basecoat and put a single stage label on it. When you mix hardner and reducer for single stage in a base coat it might end up as a really flexible film that won't dry or cure completely. Most good urethane single stage paints today will stick to an UNsanded surface, let alone 600-1000 grit, as long as it is clean. To prove this, remember how long it takes to "wear" off the single stage urethane paint that gets on your hands and fingers if you don't wash it off with thinner right away.


I would agree that 400-320 grit would be better for mechanical adhesion, but clean is actually more important, for adhesion, by just a little bit. About any brand of good quality primer (catalyzed) will work under any brand of good quality paint of a compatible system. I sold and demonstrated Dupont, Sherwin Williams, Glasurit, and RM out of the same store, and I don remember any "magic" ingredient that would prohibit using any of those good topcoats/paint over any of those good catalyzed primers. When I sold a new customer I would evaluate his undercoat (primer) system first. If he was using a primer that was old technology (lacquer), or something I was unsure of, I would sell him primer first. If his primer system was good I would try sell him color. After the customer was satisfied with my products I would sell him the complete line. You must understand that, as a paint salesman I had already been a technician/painter for over 20 years and been trained on these systems by the factories. I also went beyond the factory paint training by consulting with chemists and other technical people from these companies to help diagnose problems and gain more knowledge of how and why these systems work chemically. I gained a lot of knowledge from chemists, paint reps, bodymen/painters, and tech instructors, and I have seen lots and lots of paint problems. I am absolutely sure that I will never know everthing about paint, but I am still trying to learn more, which is what every painter should do. The worst problem I have seen is the painter that gets comfortable with one system and stays with it because he is too lazy to learn more and misses out on new technology that could improve the quality of his work and make it easier to do his job.

I am NOT advocating everybody mix brands of paint and primers. Paint companies want to sell you the "whole" line, that's good business. A good painter will learn more about his craft and products and improve his skills and workmanship in doing so.

overspray

 

+1
too much time. i use that nason primer all the time. i usually shoot the color within 2 hours, less if it's hot. after it sets, even if you scuff it up, you're supposed to re-apply the epoxy-primer before shooting a top-coat

 

EVERY car, bike Ive painted I have shot the base color over wet sanded 600 grit, the base/clear recommend it, but like I said thats Urethane Base/Clear and i have never had lift problems. I have always used Nason 2K primers and Ive shot PPG, Dupont and HOK base colors over them without problems, and I have always used Nason 496 or 497 for the Clear topcoat. I have shot Dupont Single Stage ChromaOne one the exact same setups and had no problems there either. I also have completely masked several jobs (flames, graphics, etc) after about 1-2 hours of natural drying time on the base color and had NO LIFT ay all. I also dont bekieve in sanding Epoxy Primers.
I think if you were serious about "accidently" shooting wax before the base you would have seen an immediate reaction....

 

600 grit is the correct grit. Most paint products now days will require that as a minimum, as in even 800 is good.. You should have done a wet on wet with the epoxy though if your using it as a sealer, or if you wanted to sand throw on a couple coats of urethane primer instead. most epoxy is not really designed to be sanded, unless you get some that specifically says it is. I would sand it again and use some red scotch brite to make sure its scuffed everywhere and spray it again. It doesn't matter if was basecoat or whatever there is no way anything should ever peel like that.

 

Yeah, from what I've read in the different paint data sheets, when you use epoxy as a sealer, you have a certain window of time that you can recoat it. If you had just sprayed the epoxy, and waited maybe an hour, and then shot the base coat, it probably would have stuck okay. When the epoxy sits around too long, it gets too hard and it's tough for other paints to get a chemical grip on it.

See if you can get "product data sheets" on all of the different paints you used and read all the fine print. I'm guessing the epoxy was just too hard and beyond the window of recoating time, and 600 grit was too fine to get good adhesion of the base coat.

(By the way, I'm no expert! Just an amateur who reads all that product data sheet crap religiously before I start painting, because I'm always paranoid something like that peeling problem will happen)