Lots of dust on clearcoat

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PostPosted: Mon Jun 01, 2020 12:59 pm
tomsteve wrote:
heyhi1 wrote: It was the last of the clear coats that I noticed it on

https://photos.app.goo.gl/r2ThGoHdXUKEz2Gr8



any chance this is solvent pop?


Yep!
Either his compressor is too small for the spray gun or it's very badly adjusted.
Large droplets, not enough flash time, etc.
1968 Coronet R/T


ACTS 16:31

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PostPosted: Mon Jun 01, 2020 1:54 pm
C'mon fellas. You know what this is.

Not solvent pop - no little round craters. Not from using P400 under base either. :twisted:

See how the droplets are large and not flowed in to each other? Notice the white stringy bits? Ignore the actual dust.

Final clue:
heyhi1 wrote: I didn't see it on all the other coats It was the last of the clear coats that I noticed it on


Dennis was on the right track. :wink:
Chris

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PostPosted: Mon Jun 01, 2020 2:46 pm
Blistering would be my second guess but honestly the causes and symptoms are very similar and the picture isn't the greatest.

Blistering:
CAUSE_____________________________________________________
(A) Moisture trapped beneath the paint film due to:
1) Improper dry time after wet sanding;
2) Contaminated air lines;
3) Spraying in extreme high humidity conditions.
(B) Using a poor grade and/or too fast evaporating thinner/reducer for spray conditions.
(C) Trapped solvents from applying wet heavy coats with insufficient flash time between coats.
(D) Improper dry time of undercoats before topcoating.

(E) Painting over grease, oil or rust.

Solvent Pop:
CAUSE_____________________________________________________
(A) Liquid solvent (thinners/reducers) becomes "trapped" in the paint film when the surface layer skins over too quickly, preventing their evaporation into the atmosphere. Solvents that vaporize within the paint film leave bubbles, pinholes or craters as they push through and "pop" the surface.
Solvents can be trapped due to:
(1) Thinner/reducer evaporating too fast for spraying conditions;
(2) Inadequate flash time between coats;
(3) Excessive film thickness or "piling on" of heavy/wet coats;

(4) Too much air movement causing surface to "skin over" before solvents evaporate;
(5) Excessive purge/flash time before force drying.
1968 Coronet R/T


ACTS 16:31



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PostPosted: Mon Jun 01, 2020 3:05 pm
NFT5 wrote:C'mon fellas. You know what this is.

Not solvent pop - no little round craters. Not from using P400 under base either. :twisted:

See how the droplets are large and not flowed in to each other? Notice the white stringy bits? Ignore the actual dust.

Final clue:
heyhi1 wrote: I didn't see it on all the other coats It was the last of the clear coats that I noticed it on


Dennis was on the right track. :wink:



ALIENS!!! :happy:
with reeeeealy small feet walkin all over it?? :knockout:



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PostPosted: Mon Jun 01, 2020 3:57 pm
tomsteve wrote:
NFT5 wrote:C'mon fellas. You know what this is.

Not solvent pop - no little round craters. Not from using P400 under base either. :twisted:

See how the droplets are large and not flowed in to each other? Notice the white stringy bits? Ignore the actual dust.

Final clue:
heyhi1 wrote: I didn't see it on all the other coats It was the last of the clear coats that I noticed it on


Dennis was on the right track. :wink:



ALIENS!!! :happy:
with reeeeealy small feet walkin all over it?? :knockout:


:rotfl: :rotfl: :rotfl: :rotfl:

Snorted my Beer out my Nose OUCH! that BURNS!
And still im not gonna guess with that picture, But I do see little craters or little foot steps when pic is enlarged but I am getting old and my eyes no see so good anymore.

I have to hand it to the guy though 5 posts nd hes got clear on his bumper It all has to come off and be redone but what the heck I give an A for effort a D- for doing his research before applying materials and an F for results as it needs to be sanded down and do over.
Dennis B.
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.



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PostPosted: Mon Jun 01, 2020 5:57 pm
badsix wrote:you need to tell us a little more like where were you doing the spraying. is it on the car? what clear and activator, what was the temperature. did you use a tack rag, although it looks like its gotten on it after it was sprayed? one thing for sure in the picture you need to get your spraying technique down better. maybe slow down the mixture some, maybe up the air press. you got a BAD case of orange peel. wet sand the bumper with some 600 and reclear.
I went back and looked at the picture and I don't think its dust. you couldn't get that much if you painted out in the desert in a wind storm. I think you could have a problem with your clear or activator or somewhere, I think your probably spraying It on.? it'll be interesting to see what others have to say.
Jay D.

I did the spraying in a tent closed all the openings with plastic painters drop cloth.
The temperature was around 75 degrees Fahrenheit
I forgot to use a tac cloth but I cleaned the primed bumper really good dawn soap water. I've been hit it with prep all wax and grease remover , and rubbing alcohol last.
600 grit was my prep for the base
My base coat is matrix mpb . What I did with this was I was afraid to get runs so I set up my gun by spraying a piece of cardboard where the fan pattern was about 6 inches,oval and even coat on the pattern. holding the gun still for about 2 seconds with no runs is where my setup was It was around 30 PSI
My gun is sprayit 30000.
SPRAYIT SP-33000K LVLP Gravity Feed Spray Gun Kit https://www.amazon.com/dp/B008FDMXRW/re ... 1Eb98WXYAQ

My compressor.
https://www.harborfreight.com/21-gallon ... 61454.html
Clear coat is refinish solutions RSC 220 with rsa 226 hardener which I think is a medium hardener

So what I did with the base coat is I was scared to get runs so I did about four coats with 15 minutes flash time exactly in between. The first two coats light last 2 a bit heavier. I got a tiny run on the second coat and since it was light I was able to send it out with 2000 grit after my final base coat before I cleared.
I waited at least a few hours before I started to clear maybe 2 hours or so
Now when I went on with the clear coat as I was setting up my gun I got about a 8-in pattern but again I was afraid to get runs so I think when I set up the gun and I held in the trigger for a few seconds there wasn't much clear on the surface but I left it that way so I wouldn't get any runs I figured I'd do a few more coats to make up for it. So I hit it with two light coats and two medium coats. It wasn't till the last coat that I noticed all this crap all over
as far as my compressor setup I don't have any filtration The only thing I have is one of those orange balls you put before the regulator on the gun itself I think it's for water. I also took out the filter in the gun because I heard it clogs and I always filter the paint before I put it in the gun. It was a 1.3 tip on the clear coat I think 1.5 for the base

https://photos.app.goo.gl/MkP2jT3y1jMwt6VK9

https://photos.app.goo.gl/TQjt5aQV1TxEsL767

https://photos.app.goo.gl/kaYFiE4Stqr6iN787

https://photos.app.goo.gl/fehzsBZHoQQfHQSW6



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PostPosted: Mon Jun 01, 2020 7:11 pm
:goodpost: ^^^^ how old is the orange thingy you have on the gun? if its not new i'm wondering if its not coming apart inside and you spraying it out. just an idea, I had a friend that had a similar problem. I get the idea that runs scare you, don't let it bother you. its much easier to fix a run or two than what you have now. that's where you get your best finish just before it runs. I do think you really need to get your act together before you do the hood oh and also the mid temp activator is probably to fast at 75 your in the upper limit.
Jay D.
they say my name is Jay



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PostPosted: Mon Jun 01, 2020 7:49 pm
https://www.matrixsystem.com/export/sit ... SC-220.pdf
Jay D.
they say my name is Jay



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PostPosted: Mon Jun 01, 2020 8:09 pm
badsix wrote::goodpost: ^^^^ how old is the orange thingy you have on the gun? if its not new i'm wondering if its not coming apart inside and you spraying it out. just an idea, I had a friend that had a similar problem. I get the idea that runs scare you, don't let it bother you. its much easier to fix a run or two than what you have now. that's where you get your best finish just before it runs. I do think you really need to get your act together before you do the hood oh and also the mid temp activator is probably to fast at 75 your in the upper limit.
Jay D.


I've only used it to prime base clear the bumper and prime the hood

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PostPosted: Mon Jun 01, 2020 8:19 pm
Do you have picture of what the base coat looked like before the clear? Something close up would help.

Did you read any of the articles on the Info Center? Gun set up and spray patterns are covered, plus air filtration/water trap systems and a number of other things to help.

As a beginner you need to accept and following the instructions of the more experienced painters. Failure to follow instructions will cost you time, money and a lot of unnecessary work.

If you don't listen to and heed the advice given, don't expect us to keep wasting time answering your questions.
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ACTS 16:31
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