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Old 04-27-2012, 10:59 PM
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small divits in clear coat

i did a full paint job along with body work, used omni base and high solids clear coat.
the car was epoxy coated 2k primered wet sanded, 2 k primered a 2nd time, wet sanded, epoxy sealed 3 coats there was a issue with the final coat so that was dryed and wet sanded at 600, based 3 coats, cleared 20 mins after base applied, 3 wet coats, let dry for 3 days wet sanded at 600 applied graphix's washed with mild soap and water rinsed well dryed let sit 2 days to air dry. wiped down with wax and greese remover { wipe on wet wipe with dry clean towel} then 4 wet coats applied 20 mins between coats and was tack tested inbetween coats. let dry for one week.
wet sand down to 3000 grit washed and dryed, waited 3 days cut and polished.

ok heres the problem, during the wet sanding these little divits were not there, during cutting they werent there. i cut one day polished the 2nd, after the polish they werent there. 4 days later, i start seeing a couple of these divits here and there but not in a group or any where close to gether. several days latter while assembling the car im starting to see a couple more but not like fish eyes in one spot or solovent pops in one area, there like 3 foot away from each other and there smooth just like there was a crator there before hand, but with the amount of prep i put into it with the wet sanding and all and them not showing, but after cutting and polishing and several days later. after polish the area was looked at with a sun gun.
if any one knows what this is please let me know, there was alot of dust in the clear. but everything seemed to come out in wet sand and cutting.
and can i rough up the divit a bit and dab in some clear to fill the area then wet sand and buff those areas again.
please i need some ideas.

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Old 04-28-2012, 02:12 PM
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when you use four coats in one spraying it should only be for your second round of clearing to hide stripes(my 2 cents), and not all the coats are applied wet, you gradually decrease gun speed and your last coat is wet. You also have to give it longer flash times. When I hear four wet coats and twenty minute flash times I'm instantly thinking solvent pop, or in your case solvents suspended in the clear and you just sanded to them to open them up, or they worked their way up. If it's black you would have been able to see them instantly but sometimes the color will hide them. I have a hunch this is what you're dealing with. Four coats is living on the edge without the proper reducers, flash times, and spraying techniques.
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Old 04-28-2012, 04:10 PM
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Some clears, like PPG Concept, will shrink for a very long time. If an area was still swollen with a lot of trapped solvents, you may have sanded it flat on a high spot, only to have it sink in as the solvents slowly escaped.

An example would be when I allowed the paint on a Shelby Mustang to dry about 4-5 days... sanded out a couple runs in the Concept clear, then buffed a couple days later. Looked good! Two weeks later, the spots that had runs sank in creating "dips" in the shape of a run. Undoubtably the most unstable catalyzed clear I have ever used!

I called a guy on a chat group who only uses the Concept line, and he advised me to wait six months, then sand and buff again..............

SAY WHAT!!! I need products that work every time, and also allow the jobs to be completed within a reasonable time. I will never leave my DC92 Diamont again! :-)
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Old 04-29-2012, 01:54 AM
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Quote:
Originally Posted by tech69
when you use four coats in one spraying it should only be for your second round of clearing to hide stripes(my 2 cents), and not all the coats are applied wet, you gradually decrease gun speed and your last coat is wet. You also have to give it longer flash times. When I hear four wet coats and twenty minute flash times I'm instantly thinking solvent pop, or in your case solvents suspended in the clear and you just sanded to them to open them up, or they worked their way up. If it's black you would have been able to see them instantly but sometimes the color will hide them. I have a hunch this is what you're dealing with. Four coats is living on the edge without the proper reducers, flash times, and spraying techniques.
i used the proper reducers from the jober and also verified by the ppg tech hot line, and i also was informed by both the ppg tech and bye a colision repair guy that i know that watched me paint the car. and tendid the hose for me. and both said that it would be fine to do 4 coats at on time. the car was based cleared in one day waited 3 days then wet sanded, the graphics was applied that took 3 days to do because of work. the graphix's was painted and and cleared. it was untaped a day later scuffed then washed with water and mild soap rinsed well, dryed waited several days then wiped down with tack cloth. wiped down leberaly with wax and grease remover and wiped with clean dry towel while still wet. the car was again tack clothed. then the 4 coats was applied. inbetween each coat the paper was checked with gloved hand and it was not sprayed untill it was tacky but didnt leave a stringy mark. then the second coat was applied, it was a thin wet coat like the first coat, checked in the same maner 20 mins was a estamated time because i waited 20 mins. checked for tack if it wasent good i waited, even when it was at the right tack there was still time added because i mixed my clear as i neededd it then waited 5 mins before spraying, then i sprayed small parts first then sprayed the car. the last 2 coats were heavy wet coats and i forgot to mention each mix was reduced with the proper reducer 10%, the last coat for flow was reduced a tad more.
then it was left to dry for at least a week then it was wet sanded 1500 no problems, second day 2000, no problems it was a day or two before i could get to the 3rd wet sand of 3000 trizac pad da, and the car was washed with mild soap and rinsed well and dryed no problems spoted in all the steps, it was several days while i did touch up areas by hand, washed well rinsed still no problems. the car was buffed with a wool pad with 3m perfect it compound, waited 2 days the polished with number 3 3m perfect it foam pad polishing compound. and there was none of these spots. a week later i go to start assembleing the trim on the car and i start seeing some areas where this started.
altough you might be 100% correct, after a month why would it wait that long to show, when the wet sanding process lasted almost 2 weeks then wasent buffed for several days later.
any ways the person im doing the car for is happy with the job very happy infact but im not, this is the first time this has happened to me and ive done several cars with no problems with long lasting finishes. can i re wet sand at 2000 then 3000 then cut and polish it its only on the hood and roof and truck lid but mostly on the hood, can i do this with out makeing things worse??? thanks for your help. i cant afford to repaint because im out of a place to paint right now. should i first dab in some clear coat after scuffing the area up a but to fill the small spots that are sunk, they look as if a ball point pen was jabbed into the clear before it was dryed up. its smooth and theres no blow out area like normal fish eye marks and are very sparatic.
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Old 05-03-2012, 11:07 PM
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We used to see this problem with epoxy primers as the take so long to fully cure, example Ppg's dplf with 401, it will flash and you can paint over it but it is still drying underneath, Then you put a clear over it and the shrinking begins, Change to a 2k sealer like Ppg Dps series or compairable and you will see this problem go away, I thought the same thing years ago as I was a believer in epoxy, use it as a primer not a sealer and your problems will be few.
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Old 05-03-2012, 11:24 PM
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Quote:
Originally Posted by paint dude
We used to see this problem with epoxy primers as the take so long to fully cure, example Ppg's dplf with 401, it will flash and you can paint over it but it is still drying underneath, Then you put a clear over it and the shrinking begins, Change to a 2k sealer like Ppg Dps series or compairable and you will see this problem go away, I thought the same thing years ago as I was a believer in epoxy, use it as a primer not a sealer and your problems will be few.
thank you finaly something that make sense to me, personaly i dont care much for the omni brand epoxy primer every time ive sprayed it it seemed to always have a problem with something, temp wasent perfect, or the cat. was old, not enough reducer to spray right when mixed by the spec sheet. inproper air psi settings stated on the spec sheet. personaly i wont use it again on another high end job, ill use just regular base coat it serves as the same thing ans theres less problems. thnks for the advice
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