Where to go from here? Moisture pimples

I think I may have been putting too much clear on for the conditions? I think I have enough CFM because my wall never drops below 100 and my gun reg is always a solid 25psi.
I am hoping to see if cutting with 1000 and then a single flowcoat will remove the defect.
My only problem with just buffing them out is the defect is very pervasive and shows up on edges and inside corners and other parts of the car that are challenging to buff without burning.
With the super long recoat time of 24hr with UV clear I may try super extended recoat time of 2 hours, next time I use this clear. This should at least allow the defect to appear and subsequent coats to "fill it in".
I'll keep at it!
 
Be careful with extended recoat times. At some point, it will pinch up on you. That is where the recommended 30 minutes comes from.

Don
 
A 2 hour recoat...is that possible?
I'm not sure, I'm just trying to think outside the box to help mitigate the issues I'm having. I was thinking about adding a condenser unit in my airline before the water trap to cool it. a refrigerated dryer is a no-go because I don't have the space or electrical power frankly to run it both with my compressor. The car continues to die back, lose gloss and fry up worse every day.

I did an experiment with a door and the trunk.
I cut the defect out of the door with 600 grit and hit it with three coats.
Trunk was still in basecoat, I applied three coats to it as well at the exact same time as the door, coat for coat.
the defect did not reappear on the flow-coated door after one week but has appeared on the trunk quite badly that was sprayed over spi base.
the results of my experiment make me even more confused honestly!

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What is under the base? What reducer did you use for base?

Don
sealed with SPI epoxy that I reduced 15% with SPI Med urethane reducer to get it to smooth out a bit. next day 4 coats SPI base/spi med reducer. next day uv clear, 45 min flash time. garage temp drops to 60f overnight.
 
I think that was too little reduction of the epoxy sealer. Typically 30% for overnight plus it sounds like it was too cold for the epoxy. I wonder if it cured properly. Whether or not this is your problem I can’t say.

Did you apply a wax and grease remover to the epoxy before base? Did you apply a wax and grease remover to the base before clear? Did you apply wax and grease remover to your sanded clear before more clear? What wax and grease remover and how long did you wait?

Don
 
For the trunk I just used a Gerson tack cloth and lightly touched the car with it before base. next day immediately before clear I also used the same tack cloth. No W&G Remover on the base, I didn't want to touch it. I very lightly dragged the tack cloth over the base before clear.
For the Door I wetsanded with 600 in a bucket of water with some dawn soap. I would wipe it down and dry it with paper towels to check the texture. Once even I used water in a spray bottle to wash off the slurry and dried it overnight, then next day used the same used gerson tack cloth on the panel immediately before shooting.
I can't tell as of yet if I have a moisture problem, or just as AAE suggested in the first post to this thread, contamination that I can seal off using universal as a "barrier coat"
 
Maybe moisture? Barry stated a 30 gallon tank 50ft from the garage? Small tank and I’m assuming a high rpm compressor that’s working hard to keep up she’s probably a water pump. That water needs to cool and get caught in drops and traps. What are you using for piping and filtration? A Tranny cooler and trap with auto drain plumbed inline between pump and tank work great for keeping a majority of the moisture from hitting the tank. You’ll still need drops and filtration afterward but it helps a lot.
 
The pimples look whitish in the center which I assume is your epoxy sealer. I think it’s something percolating up from your epoxy which was not adequately cured when you applied base. Your conditions are too cool for epoxy imho, especially when it was under reduced. Did you apply one coat of epoxy sealer?

Insert mandatory backyard hack disclaimer here…. :D

Don
 
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Thanks for the feedback everyone!! it makes me feel like im not in it alone.
My next step is an aftercooler setup, last resort being adding another breaker and circuit and buying a refrigerated dryer.
It's strange, subsequent flowcoats seem to turn out okay tho, so I wasnt sure.
 
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I guess I’m not understanding how it can be air contamination when two items are sprayed in the same session but only one has the issue. I would have thought both items would have an issue. I think it’ might be something else.

Don
 
I guess I’m not understanding how it can be air contamination when two items are sprayed in the same session but only one has the issue. I would have thought both items would have an issue. I think it’ might be something else.

Don
Exactly, I spent a lot of time on the phone, and if I was given the honest answer to all my elimination questions, the problem is all SCFM and his 30-gallon tank compressor that is 50 ft away from where he is painting.
These are not fisheyes or solvent pop.
These are co2, and some are so bad it has iso-clumped.
The bottom line is scfm is not breaking up paint and blobbing on, and the tin is sucking humidity trying to force-mate it with the iso, just as I said happens in a run.
 
Maybe it is something to do with my compressor, I'm just not sure how. My wall psi doesn't drop below 100, 28 at the gun, isn't that what's important? I added an aftercooler and refrigerated air dryer but it didn't help. Maybe it is also my technique? I did end up with a run or two.

I sanded the whole car flat with 600 and put 3 more coats of universal clear, panel 65f, 65% humidity, med reducer. The next day the whole car has solvent pop and dieback again. Not sure why the one door I painted turned out perfect...

I've shot the whole gallon of universal now, maybe I could have better results with Production clear next time?
 
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It's not about pressure, it's volume (CFM) that is causing the issue. Pressure and volume are independent of each other. Blow through a straw, you will have high pressure but little volume. Blow through a 2" pipe, you will have low pressure but more volume. Your compressor probably isn't able to provide the amount of volume (CFM) that you need with the gun you are using. Therefore you get the CO2 gassing iso clumping because you don't have enough volume to break up the paint (as per Barry's post above). Get a bigger compressor and the issue will go away.
 
It's not about pressure, it's volume (CFM) that is causing the issue. Pressure and volume are independent of each other. Blow through a straw, you will have high pressure but little volume. Blow through a 2" pipe, you will have low pressure but more volume. Your compressor probably isn't able to provide the amount of volume (CFM) that you need with the gun you are using. Therefore you get the CO2 gassing iso clumping because you don't have enough volume to break up the paint (as per Barry's post above). Get a bigger compressor and the issue will go away.
Thanks, Maybe I'll stick to doing panel by panel? is a lower solids clear like euro or production more low CFM friendly?

the part I'm not understanding about CFM versus PSI is isn't the paint gun a fixed orifice size? if you can blow through that paint gun with trigger all the way open and the pressure never drops below 100 PSI shouldn't that mean I have enough CFM? I'll definitely be taking a close look at this.
 
Is the fact that these are such high solids clears make this worse? If someone used on of the majors cheaper 4:1 clears maybe no? Jc630, acme 710/720, etc? Not that I’m recommending them over spi by any means just curious. Even spi “lower” solid clears are still pretty high. Which is a good thing. But maybe not for people that dont have the proper equipment?
 
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