Solvent Pop in Clear Coat... First Time painter
 

I rushed a paint job a little last night I think.
I waited 10 minutes between color coats and 30 before I started clear coats.
After the first clear coat went on I noticed spots that were clear voided like little craters. So like a newbie idiot I waited 10 mins and put on another clear coat.
After the third clear coat most of the little craters will filled in but not all.
That is when I noticed little bubbles like in soda pop just jumping off the surface.
I figured the piece was no good anyway so I hit it a light coat of pure thinner.
The thinner flowed the clear really nicely but I was still getting the little pops and now I had a clear run.

The color coat came out AWESOME but the clear is wavy and has little tiny bubble pops in it.

So my questions are.
1. Is 10 mins the minimum between coats and is it ok to wait longer?
2. Is the color coat supposed to go from shiny wet to a dull dry look before applying the next color coat.
3. Should the color coat be completely dull before I start the clear.
4. Was the little crater looking spots "fisheye"?
5. Was the litlle soda pop bubbles fizzing off the surface "Solvent Pop".

I am new to painting and this is my first attempt (did a trashed sunroof panel for practice).

Some important background, I cleaned and degreased the whole panel, sanded the panel smooth, primed the whole panel (etching primer might have been a mistake too.), hit it with a scuff pad, degreased again, then used a HVLP gun at 20 psi input with correct filters and water seperators. I also ensured the mixture of paint to reducer was correct. No hardener was used.

any suggestions would be really helpful as all the stuff I find online acts like I should already know what I am doing.
Really Thanks for advice!!!

your crater spots sound like fisheye. do you have a good water seperator on your air supply? sounds like you waited long enough between coats, but that's just a guess since you don't mention exactly what type of paint you are spraying.

It is a PPG product, 2007 charger red (sunburst orange / Hemi orange) Base coat Clear coat. I will have to go home at lunch and get the exact brand and stuff...

P.s. Most of the sites say the fizzing is because I didn't let the previous coat dry long enough.
Maybe I put it on too thick?
JC

You asked lots of questions, but here we go:

You only need etching primer if it's over bare metal. If not, then I like to you a medium or high build primer that lets you sand it out with plenty there.

Depending on witch reducers and activators you used, your problem could be many things. Time is not an absolute, you have to see if the paint is dry. You can do this by checking a spot of overspray on something you masked. It should be pretty much dry. A little tacky is probably ok. Color should be completely dry before clearing (probably 20-25 minutes to be safe.

Fish eyes look like little craters that form fairly quick after you apply the paint. It's actually something on the surface that is "pushing" the paint away. You could replicate it by spraying some spray paint on something that has some silicone or oil on it.

Solvent pop usually takes a little bit of time to form. It's the VOCs and solvents from the previous coats coming through the top coats. Looks like little bubbles in the paint that end up exploiding on the top surface. I think PPG's website has lots of good info and pictures of paint conditions on it.

Cool... I will head back over and look at the PPG sight again.
I used google and didn't find what I was looking for but I might not have done the search right.

About fisheyes. I didn't have them on the color coats. Just the clear. Does that mean there was contamination under the paint or something?

solvent pop usually means you have too much of something in there- are you mixing the color correctly? Use a measuring cup-have them at the paint store- to make sure its correct- too much activator would do it. Etch primer-only over bare metal- def want to use a mild/high fill euro primer before most paint, then 500 wet dry to prep. Most new eurethane paints w/ clear, you only want to go two coats of clear unless otherwise indicated- it will run like a monkey. Putting straight thinner over the surface is an old laquer paint trick- really dont want to do that on a eurethane paintjob- ive heard of doing it to blend a panel but if your getting a solvent pop- most likely color was not dry to the touch- you are just making it worse. If the job dries and it looks good besides the solvent marks, you may get away with just sanding and buffing it - or at worst wetsand 1000+ grit and reclear it- one coat. Usually i'll wait 15minutes between coats and half an hour between coats of clear. Also depends on if you are using a cold reducer, mid temp or high temp and how cold/hot it is outside- if your using a high temp reducer and its cold- it will take longer to dry and possibly solvent pop due to layers soaking into one another.

Awesome ..... was just there... I shoulda went there first instead of google....

Answered most questions...
But just to be sure can you wait longer than 10 mins between coats or is 10 mins like the golden rule for this type of paint.

If you are supposed to wait 8-10 minutes between coats according to the data sheet is that minimum or maximum time?

I am pretty sure the solvent pop is I didn't let the previous coats dry long enough.
I guess I shouldn't have tried to paint on a weeknight LOL....

with eurethane paints, w/ a clear coat, you should be able to touch the surface(dry) before you apply the next coat. If it hasnt dried to a flat looking surface, its not dry. For example, often times i will put down a coat of paint, five minutes later -in the summer- its dry enough to wet sand out anything i see that i dont like, then i'll put a few more coats on- waiting until its dry between each, wetsand again, and then clear or put one more coat on before clear.

Yeah it's poly urethane....
Do I have to wet sand between coats?
My color coats came out awesome I just had trouble with the clear.
Or do you just wetsand whenever there is a minor imperfection you need to get rid of.

You don't ever *have* to wet sand. You can at just about any point if you want / need to. I sprayed my car 4 years ago and haven't wet sanded anything. We didnt' get any real dust in the paint and the surfaces are all pretty good. I'll get around to it at some point.

All the drying times you get on data sheets are approximate. You really need to check the paint and not a clock.

ahhh... so if the paint has dried say 15 minutes and looks and feels good then shoot the next coat but if it still has shine and looks "wet" don't!

What is the longest between coats are we talking hours or minutes?
I know that the clear coat said not to wait more than 12 hours to clear or lifting will occur.
So if I wait a little longer than necessary that won't hurt anything right? you know extend the 10 mins into like 20 just for good measure (especially if the temp is a little on the cool side?)
:icon107:

Question on safety. What are you guys using for protection from paint fumes? I got the paint to do some touch up work (first time painter) and as I read about the ISO's and the damage they can do if not properly protected. They reccomend supplied air systems and full body suits for these new base/clear coats.

I guess they do.? I wear a jump suit and a regular paint resperator since I am not doing production work but maybe I am being dangerous?? I do know that if you get too much exposure it can casue daim bramage. .......

http://www.ppg.com/cr-refinish/phase...uide#Equipment

I would say you may end up waiting ~30 minutes, sometimes up to 45 with certain clears. Certainly waiting 15 minutes instead of 10 will never cause a problem.

For protection, I've never used a forced air system, although they are the best. We've always just used a resperator, glove, tyvek suit, ballaclava. Had a spray booth too.

i wear a 3m disposable paint mask - good for 15hrs booth time - i dont wear eye protection though i prob. should.

The time between coats shouldnt be looked at in time- i should be recoated when the first layer is flashed off- or dry to the touch- if it takes along time then you know you are using to warm a reducer. I love painting w/ mid temp activators on hot days when it flashed within a couple minutes- awsome! You dont need to sand between coats, i do because im a perfectionist - or i messed something up- dont wait more than eight hours to put the next coat on or youlll risk paint flaking down the road. The can says closer to 24hours but trust me- 8 hours tops.

AWESOME answers you guys ROCK...
I may have to create a painting powerpoint after this LOL...
Painting 101 for Porsche Owners....

I have generally heard that extending the flash time a little does not cause any heartache. Too little flash time, or too heavy a coat, can cause solvent pop.

I use a forced air system (Neoterik) with a full hood and 50 ft. hose. It is the safest option, although many people seem to do just fine with a good (i.e. new) respirator. I also use a 3M respirator under my hood as a back up. The fresh air system was only a few hundred bucks IIRC. Definitely worth it for my own peace of mind.

What is the best way to see those imperfections that need wet sanding in the color coat?
I tried looking from every angle but until I got outside in sunlight and stood at an angle did the scrub stuff show up.....
Is there a trick to holding a light? Or the type of light (hand held flourescent vs halagon)?

floresent lights usually show the most flaws- or natural light. I was watching a ding doctor guy once removing some dings and he took a large board and propped it up on a ladder next to the car- the reflection of the color of the board made things easier to see. The color coat just put your nose to it and get any dirt/ sand lines etc out best you can...

Cool.. I will go get another flourescent drop light and try that...
Thanks Again dor all ya'alls help

it's been my experience, and it seems that you're understanding this too, that with paint, you've gotta let it "flash" for 10-15 minutes depending on the temp. before you lay down a second coat. it also seems to me that the fisheyes you're getting may be caused by contamination. if there was dust in the air, and it landed on the setting paint, that could be the cause...

but I'm no pro-painter. anywho, for protection, I used one of those nose-mouth masks that's held on by a rubber strap... at first I was goin w/o a mask... 2 breaths and my nose started bleeding (or it was the red paint and it got up my nose...and burned a hell of a lot) but yeah...a respirator is a DAMN good thing.

Usually these craters or fisheyes are water contamination. It is rare dust would do it. Dust or dirt in your clear is not that big a deal because all good paintjobs should be wetsanded and buffed. These contaminants sand right out. It will make your paint look very dull, but wit will come back up with proper compound. I use 3m heavy cut and follow with fine, then I buff the hell out of it with 3m's new Ultrafina. Makes a relatively bad job very very nice.

usually fisheyes are caused by oils or petroleum substances- bodyshops wont let you have wd40 within a hundred yards usually if they do any type of paint work. I had one fishey on a fender once, because i had a kerosene heater sitting in the corner, covered up- not running - it had been there for some time. Just that one fender nearest to the kerosene fisheyed. Water will do it too if you have small droplets coming through the gun- looks somewhat different though- best thing to do w/ those is let the paint dry, wipe them off, wetsand and reshoot.

Ahhhhhh So perhaps the milling machine being so close with all it's oily stuff might have caused it....(I use kerosene and other stuff to mill aluminum)
Strange that the stuff should get airborne but hey weirder stuff has happened...
I suspect I need a better water seperator... Even with one in the system I saw water mist come out the hose when I first used it this week.
Maybe I can get one that mounts closer to the gun or I could try and purge the hose before painting...
Hmmmmm....

They make little plastic orange filters that you mount right on the gun.