Clearcoat boiling/solvent trapping/micro bubbles?
- Thread starter ebaypdllc
- Start date
jlcustomz
evil painter
Back on the subject of modern high end turbines, was running my 6 stage at work about 2 hours today & checked line temps several times. Room walls were 80 to 84 this afternoon, concrete floor still 76.
Output hose from unit measured as high as 186 right near unit. Numbers progressed lower & lower down the 25' hose with the 5' flex leader hose not going over max wall temps after 2 hours of use. The new units really do disperse most of their output heat before getting to gun.
Output hose from unit measured as high as 186 right near unit. Numbers progressed lower & lower down the 25' hose with the 5' flex leader hose not going over max wall temps after 2 hours of use. The new units really do disperse most of their output heat before getting to gun.
Well, there is a happy ending to this...I fixed the problem and shout out to Serjik911 he was the one that figured it out because he had same problem!
I originally started out with a Turbine sprayer that maxed out at 9.5 PSI. It was adjustable the pressure and I could spray a beautiful finish at 6.5 PSI. All the turbine videos I saw showed them dial down the turbine to about 7PSI and got perfectly nice finish on clearcoat. The problem is that with my temperature at around 60-65 degrees the clear coat is going on to thick or the PSI from the turbine was not enough to get rid of whatever solvents are in the clear. The parts were curing and trapping those solvents.
I abandoned the turbine system and went with a Quiet Air Compressor and low pressure, low air consumption HVLP gun the Iwata LPH80. They recommend you spray at 7 to 14 PSI. When I spray at 14psi I would get orange peel. When I sprayed at 20PSI I got a perfect finish but the clear was dieing back from trapping solvents. When I upped the pressure to 28-30 PSI, the solvents no longer show up as the clear cured.
When I sprayed at 30 PSI I was getting trash galore in the parts, that's when I discovered the Devilbiss QC3 I had was tampered with that I got on Amazon. I replaced it with a Sharpe Dryaire system and it solved the contamination.
Interestingly as I searched and searched this forum. I saw other people who said they had similar problems. I saw one person said he struggled with same problem and it went away when he got a new spray gun.
I am going to experiment around to find what pressure I can spray at and not get the trapped solvents. I battled this problem literally for years and spent fortune. Glad to finally have some closure. So if anyone is reading this and having similar problems , the answer is to crank up the PSI.
The new air desiccant system is ridiculous and huge compared to the QC3 lol but atleast I hope its a bullet proof system now.
I originally started out with a Turbine sprayer that maxed out at 9.5 PSI. It was adjustable the pressure and I could spray a beautiful finish at 6.5 PSI. All the turbine videos I saw showed them dial down the turbine to about 7PSI and got perfectly nice finish on clearcoat. The problem is that with my temperature at around 60-65 degrees the clear coat is going on to thick or the PSI from the turbine was not enough to get rid of whatever solvents are in the clear. The parts were curing and trapping those solvents.
I abandoned the turbine system and went with a Quiet Air Compressor and low pressure, low air consumption HVLP gun the Iwata LPH80. They recommend you spray at 7 to 14 PSI. When I spray at 14psi I would get orange peel. When I sprayed at 20PSI I got a perfect finish but the clear was dieing back from trapping solvents. When I upped the pressure to 28-30 PSI, the solvents no longer show up as the clear cured.
When I sprayed at 30 PSI I was getting trash galore in the parts, that's when I discovered the Devilbiss QC3 I had was tampered with that I got on Amazon. I replaced it with a Sharpe Dryaire system and it solved the contamination.
Interestingly as I searched and searched this forum. I saw other people who said they had similar problems. I saw one person said he struggled with same problem and it went away when he got a new spray gun.
I am going to experiment around to find what pressure I can spray at and not get the trapped solvents. I battled this problem literally for years and spent fortune. Glad to finally have some closure. So if anyone is reading this and having similar problems , the answer is to crank up the PSI.
The new air desiccant system is ridiculous and huge compared to the QC3 lol but atleast I hope its a bullet proof system now.
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rdransman
Promoted Users
I'm glad things are working for you now, but I think you need to simplify your system. I have 50 feet of 3/4" hardware store copper between my 50 year old Campbell-Hausfeld 2-stage cast iron compressor and my gun. My drops go toward the ceiling first and then do a 180 to 4 feet above the floor. I have a few ball valves for moisture here and there, and they puke a lot of water when I remember to use them. I have a cheap 40-year old sharp separator/regulator right before the hose. I use my air tools and a sand blaster with this system every day and paint something about once a month. I crack the garage doors about a foot, turn on the fans in the back wall, wet the floor and squirt. I live in the woods, so every now and then I get a bug, but every time I pick up the Sata 3000B, and it's between 60 and 80 degrees F - with the right catalyst - I get pretty much an excellent result.
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Chris_Hamilton
Trying to be the best me, I can be
None of that makes sense to me. I don't understand how it's possible to trap solvents in clear in a single coat. @Barry could you explain this? I have never encountered this in my 30 years of spraying.
Me either. I can count on one hand the times I've had solvent pop after many thousands of cars sprayed.
Yep confirmed it, did more test today. Sprayed two panels side by side. One at 20 PSI and other at 29/30PSI
The 20 PSI solvent pop consistent all throughout. Same flash times etc.The 29 PSI part looks perfect...
Also sprayed this black part at 30 and no solvent pop on that either.
Serj had the same exact problem and we paint in same conditions 60F. Cant thank him enough for helping me!
The 20 PSI solvent pop consistent all throughout. Same flash times etc.The 29 PSI part looks perfect...
Also sprayed this black part at 30 and no solvent pop on that either.
Serj had the same exact problem and we paint in same conditions 60F. Cant thank him enough for helping me!
What is interesting is if you look at the parts outside, or under LED light you can't see the solvent pop. Its only in certain lighting...Very faint as you can see in the picture.
I'm just glad its working at this point. I'm going to try the other brand clear and see if it fixes that also, should be the ultimate test.
Chris_Hamilton
Trying to be the best me, I can be
Trying to remember the last time I had solvent pop (which is slightly different than trapping solids) and only time I can remember was iver 10 years or so ago and I was spraying a replacement front clip of a Freightliner in 100+ degree temps and using some very crappy Transtar Euro Clear. (Painters that die and go to hell have to spend eternity using Transtar clears
) It popped as soon as I was laying it down. Other than that I can't remember a time. Conditions you were painting in trapping solvents in the clear should not be possible especially if you were laying it down as slick as those pics make it appear. Just doesn't make sense.
) It popped as soon as I was laying it down. Other than that I can't remember a time. Conditions you were painting in trapping solvents in the clear should not be possible especially if you were laying it down as slick as those pics make it appear. Just doesn't make sense.Is there some kind solvent in clearcoat that when you spray evaporates? Almost like when spraying at low PSI that those solvents are being transferred to the part and not evaporating out.
I have no idea...What weird to is that I tried reducing the clear thinking that would give me thinner film builds. It didnt work. Only thing that is fixing the problem is high PSI.
I also noticed alot people on youtube are spraying at 28PSI with the LPH80
I have no idea...What weird to is that I tried reducing the clear thinking that would give me thinner film builds. It didnt work. Only thing that is fixing the problem is high PSI.
I also noticed alot people on youtube are spraying at 28PSI with the LPH80
serjik911
Promoted Users
What will happen if you will spray clear with your sata at around 16 psi? I know you spray it around 30. And add poor air movement.Trying to remember the last time I had solvent pop (which is slightly different than trapping solids) and only time I can remember was iver 10 years or so ago and I was spraying a replacement front clip of a Freightliner in 100+ degree temps and using some very crappy Transtar Euro Clear. (Painters that die and go to hell have to spend eternity using Transtar clears
Iwata lph 400 suggested air pressure from manufacturer is 16 psi. I don't know anyone here who sprayed it at that pressure. Barry's setup is 27 psi(almost double) and fluid closed in half from full open! Imagine spraying sata at double pressure with half fluid? What do I mean, iwata suggested pressure is broken. It still requires either pulling pressure up or reducing the clear a lot. Spraying at low pressure will give you big droplet with a lot of solvents in it that will probably late to escape. Also add to all that poor air movement.
Just my opinion, just theory
Chris_Hamilton
Trying to be the best me, I can be
Slickness of the finish in those pics doesn't correspond with big droplets though. Lack of air movement is not critical for solvent to evaporate either. It's actually the opposite. Less air movement allows the solvent to evaporate. More air movement would cause the solvents to be trapped because the clear is "skinning over" too quickly. That is the reason Barry says to turn off your fan as soon as you are done spraying and most of the overspray is evaporated.
Like I said this is not making sense.
Like I said this is not making sense.