Clearcoat boiling/solvent trapping/micro bubbles?

After 20 mins of waiting I noticed some Bubles/ craters. It's hard to see. And I was realy tired and went home so you all will have to wait until tomorrow to see the final result. View attachment 10250

All I see in that picture is a bit of trash and some craters that are probably light fisheyes. For what you are saying to be true then the clear would have the issue throughout consistently and evenly. Not just in a spot or two. Also if solvents are being trapped then whatever is being cleared is going to dieback completely every single time. It can't be trapped solvents in just isolated places. Goes against common sense.
Like it was said in the beginning of this thread it's contamination either from an air line or on the surface or it's water or water vapor.
 
Nope...It happened every single time....I eliminated all the basecoat steps etc.

I even just did another test...I bypassed my Dessicant filter system. Sprayed at 29 PSI and no more solvent pop...

Serijk had the same problem, he also fixed it by spraying at higher PSI.
 
With all respect, strongly disagree. Sata sprays hs and uhs great at manufacturers recommend. Same as devilbiss. As walcom.
Which part do you disagree with? Didn't say those guns didn't spray great at "recommended" pressures, only said manufacturers maximum inlet psi is there to give 10 psi at the air cap. I also know in my experience, most guns sprayed high solid clears better with more than 10 psi at the air cap, Sata and Devilbiss included.
 
I just did a test, did (2) coats with 30 minute flash time shooting at 28 PSI. Its starting to happen at about 1 hour in..
This would make me believe it was your air supply. I can't see 1psi solving a problem. Glad it's fixed for you, has to be a big relief:)
 
I had this happen on the last parts i painted, but I think it just got too cold in my garage. Euro, 4:1:1.5 with 870, and medium activator. It got into the mid 60's(shit happens) in the garage.. 4 coats. 1.4 tip on my dv1-c sprayed at 32psi. Doesn't crush me too bad since it all gets cut and buffed, but it is annoying. Just little micro pinholes everywhere.

In colder temps would a longer flash time help?
 
I had this happen on the last parts i painted, but I think it just got too cold in my garage. Euro, 4:1:1.5 with 870, and medium activator. It got into the mid 60's(shit happens) in the garage.. 4 coats. 1.4 tip on my dv1-c sprayed at 32psi. Doesn't crush me too bad since it all gets cut and buffed, but it is annoying. Just little micro pinholes everywhere.

In colder temps would a longer flash time help?
Funny because I painted some parts last weekend and highest I could get my temps up to that day was mid 60s metal temps. Euro, 4:1:1.5 with 870 and medium activator. Basically the same conditions as you, but I only laid down 2 coats (collision job). Doors and fenders were mostly ok, but the hood had quite a few spots that solvent popped. I was surprised because this is the first time that I can remember having solvent pop with SPI clears. I guess I pushed the limits a little too far. I normally go 4:1:1, sometimes 4:1:1.25. Maybe that little bit of extra reducer hurt me?
 
This is zoomed way in and the phone is a $100 phone so dont expect much on camera quality :D.

Again, not terribly upset since these panels will all be knocked down with 800 and up for polishing. I'd just like to isolate the issue. This is with 4 coats at 30min flash time, but it did get chilly in there at times. low 60's.

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I dont believe its water. I have a dad500 and a motoguard filter after it and that filter is bone dry. I think this was a temp issue and a lot of material.
 
Also, the issue appears to the only on the top surfaces. Ill look closer at some parts tonight. so I suspect maybe solvents are evaporating and then falling back down after the last coat and the fans are turned off??

I am not a chemist, hell im far from a painter! so I am just throwing ideas. I dont see these issues until the next day. When I walk out of the garage its glassy AF!
 
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I can only guess, and that would be that in the low 60's, 4 coats of clear is a lot. I think they need even more than 30 minutes flash, especially the 3rd and 4th coat...?
 
Ill try adding 10 min on the 3rd and 4th coat when I paint again in a few weeks and see what happens. I always get worried anything more than 30 min. I thought I read that barry said nothing more than 45min. But again that was probably in ideal situations.
 
I looked at some of the parts a little closer last night and yep, my little pinholes are only on the top surfaces. The doors are clean and some of the parts I had to paint the underside are clean,

I am wondering if maybe on my last coat of clear(i typically do 4) if maybe I should use a slow hardener?
 
I looked at some of the parts a little closer last night and yep, my little pinholes are only on the top surfaces. The doors are clean and some of the parts I had to paint the underside are clean,

I am wondering if maybe on my last coat of clear(i typically do 4) if maybe I should use a slow hardener?
I add one ounce per sprayable quart of urethane retarder to my last coat FWIW.

Don
 
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