Hey Guys , I just sprayed the bumper on my car with a two stage, base color / urethane clear. I have not painted for years and have not used the two stage paints till last year. The 3 coats of base coat color went on fine thoroughly cleaned with tack rag. mixed the clear and hardener sprayed the first few coats of clear then started to notice these small bumps coming up? they are not fish eyes, no round circles in the middle? I thought they where from dust/dirt? they cannot be wet sanded out ,seem to be coming from the base color? they are hight spots and I am afraid to sand through to the color?
I am using "OMNI AU" clear and hardener 2 to 1 part hardener as per the can directions. I have been reading about adding reducer to the clear? the guy at the body shop supply did not say anything about reducing the clear...
Was wondering if these are "solvent pop" and was is the cause>>>>>


Thanks sorry for the long thread.....

Not enough time between coats for flash. Solvent in prior coat is still trying to flash into the coat above it.

Probably solvent pop from not allowing enough time from base to clear. Doees it look like this?

If it does, wetsand it all out then place the part in the sun for a full day to allow all the solvents to flash off.
Vince

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Well the bumps are raised and are the color of the base coat? I know I waited 30min for the base coat to flash,but on the clear I was going pretty fast on the coats......would the same happen if the clear was put on to fast?
If I sand them out and hiot the base have to start all over again....drag.

Hmmm...It sure sounds like solvent pop by the way you describe it. It's really hard to say without looking at it in person. Was it painted outside in the sun or was it really hot and muggy that day? I usually add about 10% reducer to the clear coat to help it flow out and stay open longer for the solvents to release. Was told it wouldn't affect the clearcoat. It probably changes the clear from a high solid to a normal type clearcoat. Instead of two coats clear, I put on three just to be safe..especially if I'm going to color sand and buff it.

Putting on successive coats of clear too fast can cause it. It is really to your advantage to extend the times before you do another coat. I know it is very tempting to rush it along, but it can only hurt you in the end.

Vince

__________________
Here's to you DoC, you will always be here.
My project 34
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It was perfect day 68-70 no humid. in side out of the sun. as I am reading solvent pops have pin holes and look different than what I have , no pin holes just this base colored bump that appeared somtime in the last few coats of clear.
the clear is dull till like the 3rd coat is this norm and i read somehwere that you should wet sand the base color before shooting the clear?

Not necessary to sand the base. The only time you would do that is if you went past the time for recoat, then you would have to apply another coat of base before the clear.

Vince

__________________
Here's to you DoC, you will always be here.
My project 34
http://www.hotrodders.com/forum/34-...ght=34+progress

If thats a urethane "Plastic" type of bumper and you used a regular wax and grease remover prior to applying the paint, there is a good chance that the
bumper soaked up some of the wax and grease remover and now its trying to vent out. Only fix is to sand and re do.

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I looked closer at the pops and hey do have a small pin hole in the center so I guess they are solvent pops and it was me just rushing the clear.
I did use wax and grease prep but I did not have the bumper down to the plastic . I will try to wet sand the pops out not hit the base color.....
Hey guys thanx so much for all the help and info !