Help with Solvent Pop
 

Super frustrated trying to paint a few small items like my fog light covers on the lower front bumper. If I get it wet enough, getting what looks like solvent pop immediately. Happens on first coat over primer. No fan, no heat being used.

I have tried pressures from 15 PSI to 40, different volumes, different coats from barely covering to full wet. Higher pressures seem to have fewer pops but create horrible orange peel. Lower pressures (15-20) should be correct according to Iwata. Small gun so shooting 4-6 inches away per spec.

Paint: Axalta Nason Spectramaster Ful Thane (Dupont) single stage low VOC 2.8
Activator: Axalta Nason 483-30 Ful-Base Activator
Reducer: I have tried both Nason Med Temp and High temp (slow) Reducer
Suggested mix: 4:1:2. I have tried 4:1:1 and got less pops but worse peel. I have not tried 4:1:1 with the slow reducer yet.
Paint temps: shot between 78F and 82F, inside and outside. No difference.
Gun: Iwata LPH80 with 1.2mm tip. I have also tried a 0.8mm tip.

Helpful suggestions welcome. My instinct is that it's related to the gun setup: shooting too close is causing the paint to skin and pop?



http://forums.pelicanparts.com/uploa...1662759045.jpg

That was bad luck Torch. If no one chimes in maybe post the same question and pic on https://www.autobody101.com/forums/viewforum.php?f=5

Umm, sounds like you know more than me on the subject, but all I can add is are you sure it's solvent pop and not some moisture (water) coming through.

I had a similar looking problem and our man Dpmulvan put me onto descant filters and it fixed it.

Bill,
Thanks. I Have 3 filter/driers in the lines, including one at the gun, have very carefully degreased/dewaxed and dried the pieces, so I don't think it's water or contaminants.

Your point makes me think of something I hadn't before.
Shop humidity was 18% during at least one day I painted. Maybe it's drying too fast, skinning over before the solvent can evaporate...daytime humidity looks like it was between 11 and 50% the past week... Something to think about anyway.

Thanks for the suggestion. I consulted a good friend and painter. He believes it the paint. Going to try another batch / brand this week, and pay more attention to the air humidity...

-Torch

I just painted this yesterday almost same color as yours,http://forums.pelicanparts.com/uploa...1662904862.jpg

What’s underneath did you use a wet on wet sealer? 1.2 tip is a little small.

Orange peel is too much product and not enough air atomization. Get the tds for your paint and follow it. Pressure going into the gun should be between 25 ish depending on gun. Try using a 1.3 or 1.4 tip. Also when did you prime, did you use a sealer and if so what type. Your solvent pop could be coming from the sealer or primer underneath. If no luck let it dry sand with 1500 then 2000 and see if you can get rid of nubs. Sometimes you’ll get lucky and be able to sand them and buff them out.

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I tested on epoxy primer, 2 part high build primer sealer (both flashed and also some that dried for a week) sanded and cleaned, on top of 1 and 2 coats of fully cured (a week) then 600 grit sanded basecoat, and even scuffed and super clean bare metal just to see if it could be the underlying surface.

Mini bubbles appeared on every single test panel in the same way.

I tried every 5 PSI from 15 to 40.

It's possible it's the gun. However, I followed the spec sheet for the paint to a T. A 1.2 tip should be just fine and in fact is recommended (1.2-1.4mm). Truly you can shoot small stuff with 1.2 and I have even done 0.8mm with proper adjustment to volume and pattern and distance.

If it's the gun or my lines or my technique, another brand/batch of paint will not fix it and I will eliminate from there. That's my next approach.

Looking good!

Hopefully 962 will chime in, he’s got a lot more experience than I do and I learned a lot from him over the past 5 years.

update
 

Well, I decided no harm in trying to cut and buff the fog light hole covers before repainting them.

The little bubbles pretty much buffed right out with some 1000,1500, then cut and polish.

Not sure I want to do that on my engine panel with all the recesses, which is what started this whole project in the first place. gonna think about that...


http://forums.pelicanparts.com/uploa...1662932087.jpg

http://forums.pelicanparts.com/uploa...1662932292.jpg

Some water traps are useless, what kind are you running? Compressing air causes heat the air needs to be cooled down before you can extract the water. A water trap connected directly to the output of an air compressor is essentially useless. I don’t paint enough to justify buying an air dryer but you can make one out of copper pipe. You run the air out of the compressor through about 20 ft of copper pipe then back to the compressor tank. Several ball valves at the bottom of the copper loops are opened to drain out water. Just a thought in case your still having issues

update: Went to get a color match done using PPG Delfleet Essentials single stage. No pops right from the get-go with my test panels. Color match looks stellar: better than the ones I got from Sherwin Williams 2 stage and the Dupont Nason single stage.

3 coats done. Laid on much easier and better coverage -- there are a lot of solids in the Delfleet.

Fellow customer at the paint store said a bad batch of activator caused similar popping for him doing a Mustang with Nason ful thane. Maybe that was my problem. Not sure.

Very happy with the Delfleet.

http://forums.pelicanparts.com/uploa...1663033355.jpg

well done.

Love the color too.

Glad you got it sorted, looking really good is that ossi blue??

Yes, the one and only Ossi Blue.

That’s pretty. For the lines which count, are you using proper (green 3M) making tape?

John

It's all soft edges so I didn't use green.

like Dpmulvan stated looks like water in your air supply system.
being you said you buffed them out my guess too is water in your air system. if it was solvent popping then they would be much deeper than just on the top surface.
solvent popping is caused by a few things but the main one is to much material is sprayed at one time with out letting the coats under it flash off long enough. so the top coats you sprayed dry faster than the 1st coats . with the solvents having no wet surface to escape thru and with the top layer/s more dry the solvents push thru the top layers and leave pops in them.
also with spraying to much to fast to soon you can get delimitation problems. this is because the top coat/s have dried well before the 1st coats and the solvents can't escape at all so they travel along under the more dry top coat/s and delaminate the top last coats of material. this you will not tend to see until months or even years later after the car is all finished.

to avoid water the best thing is to get a dryer system. there are a few different ways to dry the air.
there are systems that will cool the air coming out of the compressor but they are costly.
another lower cost way is to install a desiccant dryer. they remove the moisture from the air with beads.
the loop systems will work ok but there are times if your compressor is running hard that you could find some air still getting to the end of your air line.
dry air is a big help not just because it can ruin your paint work when your spraying but it could also be spraying contaminants all over when your doing body work.
a good dryer system will also help in prolonging the life of your tools also.
that moisture your getting at the end of your air hose is also going thru your air tools rusting the crap out of the insides of them.
a desiccant system will run from 150 to 700$ depending on how crazy you want to go.
the time it takes to repaint and the cost of having to buy more materials in most cases will cost you much more than a few hundred bucks to just buy a good dryer.