Clearcoat Problem: Iso Clumping or Air Entrapment or Solvent Pop?

ebaypdllc

Promoted Users
Hey Guys,

I've run into an issue that i'm having some trouble resolving. I've searched the forum and I see other's have described the same problem, and there was never any resolution to the issue.

I am using the Production clear, with Very Slow Hardener. I am using a 5 Stage Turbine with an Apollo 7500GTO gun. I have the .5mm, .8mm, 1.0mm and 1.3mm setup.

I took some time off from painting for about 2 months. Previously I was not having any problems at all.

Now whenever I spray my clear, on the first coat I am getting what appear to be bubbles consistently all over.. I am also getting some debris that looks like very small "fishing line" thats very small in size pin tip. If I spray light coat, the problem actually is worse. If I spray a double wet coat, it helps improve but still has issues. After the clearcoat has cured for about 4-6 hours, I get what looks like actual solvent pop, millions of galaxy looking dots. On black it really stands out as shown in picture below.

I've ruled out that its solvent popping because it happens if I spray very light coat and it happens seconds after spraying the first coat.

From what I read it sounds like ISO Clumping, the isocynates reacting with moisture. My concern is that I am using a turbine system which is suppose to be moisture free. I am also painting indoor with the temperature being 60F. Previously in the summer the temp would be around 70F when I wasnt having problems.

To try and fix this problem I've done the following:

Installed a room dehumidifer and my humidity is below 30%
I've used all the tip sizes from .5 to 1.3
I've tried retarder and using reducer in various combinations. I've used as much as 30% retarder.
I've tried different guns.
I went to local paint supply and bought some 2:1 ratio Euro Clearcoat, that did the same exact thing to eliminate the possibility of my clear being contaminated.
I've mixed up clear and warmed it up to about 70-80 degrees and still the problem remains.

Does anyone have any suggestions on what else I should try?

If the problem is "iso clumping" can I shoot the clear with no hardener added onto a throw away panel? Will this test confirm that its the isocynates in the hardener that is reacting with moisture?

Or is it possible that the clearcoat viscosity is thicker because its winter and 60F and it cant "flow" and let the bubbles rise? Would heating the panel and heating the clearcoat to say 100 make it runnier without the need of reducing?

My only curveball that I dont understand is that there are significant amount of mobile dealership painters who use turbines. They spray when its snowing outside without any issues.

This is really frustrating. Here is some pictures and a video.

On a black part, it really looks bad once it cures.

 

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I had a similar experience with single stage black. I had an old can of hardener (a couple years old) that was less than half empty. The first coat looked very much like your black parts, it was like I threw sand on the parts. When I cracked open a new can of hardener and shot the remaining coats, it instantly was better.
There was someone with the same kind of problem on here, and I remember Barry saying if the hardener had been opened for a while, it was prone to attract moisture and create that sort of problem. Don't know if that's happening with yours, but just a thought.
 
its not air entrapment. that looks totally different. the clear will lay out fine but just look cloudy from the micro bubbles in it. i do see some fisheyes on the blue panels but mostly what i see on the black ones looks like trash in the clear which i would guess is from the hardener. open the can of catalyst swish it around and look inside. do you see what looks like snowflakes floating around in the cat? that would be bad. do like you say and shoot some clear on a trash panel and see if it does it. i have never shot a turbine but i know they create their own set of problems. it could be something related to that but i cant offer any advise on that part.
 
I've never seen anything that bad, actually, and I have no idea other than to presume the activator has been exposed to moisture.
 
I was really banking on it being moisture contamination in the hardner or clearcoat.

The problem is I went to Eastwood which is right down road from me and I bought there 2 to 1 Euro Production Clearcoat just to see if I could spray that.

I'm getting the same exact issues the pops on the first coat. When i spray heavier, or double coat it helps it. Then after it cures I get that tiny solvent pop look which looks like the black part. On black it really stands out.

What I don't understand was I was getting flawless results several months ago. I've been talking to "nokin" he is having the same exact issue I am and can't resolve it either. The problem is 100% identical. But he is using a compressor and sata gun.

I took some time off from painting. Now for whatever reason its happening, very frustrating. I don't even know what other variable I can adjust or change to try and fix it at this point.
 
Thats what I thought originally was the humidity was high where I was painting. Its in a basement but its HVAC controlled.

It stays about 64 F all year round with humidity of 31%....

Aside from being alil chilly, I would think these are perfect painting conditions?

And with my turbine. I have one of the highend models that I paid alot money for. I have about 30' of hosing. I measure the temperature of the air coming out of the hose. It stays exactly the same temperature as the room. I think its the low end turbine models that produce significant heat at the gun.

The other user Nokin is having the same problem, and he is using a compressor with Sata gun. And he is in Southern Cali where the weather is nice...

I even tried mixing the clear with metal spoon thinking maybe mixing containers contaminated.

I've been trying all day to brainstorm a new variable to change.

What I don't understand was I was painting previously about 6 weeks ago and every job I did came out flawless. I had ZERO issues.
 

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Luckily the turbine system is very mobile. The only other variable I can try and change is the airhose to the turbine, and try and paint outside.

I'm also going to diassamble and soak my spray gun see if that does anything...
 
I'm with Crash in that I also have never seen anything that bad. Your set up is something I am not into and have no interest in, I have tried something similar when the true HVLP came out in the 80's it reduced the pressure down to 3psi and connected to the gun VIA a huge 1-1.5" air hose and it was nothing but problems and it got kicked to the curb and given back to the Devilbiss Rep. I would have someone with a compressor and spray gun give it a go and see if they have the same outcome. Mabey it is the material you are painting? are you and Nokin spraying the same or similar parts material?
 
Been messing around and got it somewhat fixed....

I believe I got moisture contamination into my clear or hardener container.

I bought another brand Clearcoat for test purposes. I got rid of the craters and bubbles all over the part.

The only issues I am getting is dust nibs out the ass and iso clumping.

I bought a 40x LED magnifying glass. I can see little white, black specks. I can also see what appears to be clearcoat clumps as if it was cured and fell into the job.

Going to completely redo my booth, to get the dust problem fixed.

Quick question, will reducing or retarding fix the iso clumping if I want to use a small nozzle gun?

This .5mm Spray tip I got sprays beautifully. I just get the clumps in the job.

Here is two pictures, one at 40x and 80x. I just wanted to confirm that this is infact "iso clumping". When spraying, it looks like tiny specs of dried clear.

My guns are cleaned throughly so its not from poor cleaning.
 

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