Clearcoat boiling/solvent trapping/micro bubbles?

E

ebaypdllc

Promoted Users
I've been battling and battling this problem and I just cannot figure out how to resolve it. I did some more testing and trial and error scenario's but I feel like I am at the end now and now sure what else to try...

I am shooting the SPI Production Clearcoat with medium activator in a climate controlled 63/67 degree room when its winter time. I do (2) coats with a 30 minute flash time. I am only doing small parts painting.

Whenever I clear, about 1-2 hours into the curing cycle, tiny little pinhole dots are showing up which to me is solvents trapped. The stuff I paint is curing correctly and looks great, its maintaining gloss its just those every so faint pinholes consistently throughout the whole part.

I basecoated a part and left it sit for 2 weeks and I got a factory painted part and recleared that. Both parts cured exactly the same so that eliminated that its anything but the clear coating process. I switched to the SLOW activator thinking that was the problem and it cured exactly the same as the medium activator. I turned off the booth fan, and I also ran the booth fan while the parts cleared it made no difference.

I've tried another brands clearcoat which is a faster clear with 2 hour cure time. I used their Medium hardener and it completely dies back and its total loss of gloss. I tried using the SPI FAST hardener with the clear and this made the process worse it total dieback.

I just don't get what I am doing wrong. I am using a Iwata LP80 with 1.2 tip.

I have the Very Slow and Urethane retarder here that I haven't experimented with.

Last idea I have is that I store the clearcoat and reducer on a concrete surface floor. I thought maybe its getting cold and changing the viscosity of the clearcoat so that it flows thicker similar to engine oil? Should I try and warm up the clear before applying it? Or should I try an even longer flash time between coats of clear?
 

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Although maybe not the issue, it's always good to have an infared gauge & at least occasionally test all surface temps of surfaces sprayed, walls, floor, and as important as any, test the material being sprayed. Cans of material if colder can take a long time to warm up without assistance. Infared heat, whether a nicer unit or just cheap 250 watt screw in bulbs heat surfaces, not air, so they are great for using in an area that gets air exchanged and putting heat into the concrete which will radiate back into the room. Also great when used carefully after flash time to quicker cure items for shipment.
It's really good to keep tabs on all your surroundings, as problems can multiply & one change may need another change. Water from compressors can be a little difficult to trap without better driers. It will go straight through those cheap water traps with the clear bottoms & drains. Plenty of other drier discussions here.

Too thick a coat sometimes can help lead to bubbling, but you'd likely have runs if that was the case.

Just to ask, I know you started out with a modern turbine unit, which at least doesn't have possibility of oil from compressor & gives out dry air ( still slightly heated). I got a Titan 6 stage for commercial water acrylic paint at work , which takes a lot of paint adjusting according to temps. Works awesome for SPI epoxy & Evercoat g-2 surfacer. I could see it working for small parts base & clear or SS painting, as many mobile paint repair guys use them. Have you moved away from using it? I messaged you a long time ago here about the turbine setup, but hadn't ever heard from you.

Also , I'd say don't bother with other brands of clear ,find one & stick with it. Production clear should be just fine for what you do. There is also the new speed clear here, which maybe could be a good choice for what you do, but it too would have it's differences to learn.
 
Sounds like you've eliminated everything but your air supply. One of those cheap desiccant filters before your gun will let you know how much moisture is in the line. If it turns pink quickly, you've found your problem. Warming up the clear several hours before use is a good idea, it sprays better at warmer temps.
 
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Looks like your are in Pennsylvania so I am going to venture a guess that your concrete floor may be quite a bit colder than your booth temps.
Try storing the clear coat in your house so it is thoroughly warm and be sure the surface temperature of the parts themselves is at least in the mid sixties.
Keep the booth warm for a couple of hours after you spray and see if this doesn't solve your problem.
 
I was having this type problem a couple of years ago and Barry pointed out my air supply, He suggested a Motor Guard M-60 cartridge filter and a desiccant before the hose outlet. I have a water separator, M-60 and 1.5 gallon desiccant in that order and all my troubles have went away.
 
Thank you so much for the replies. I've been so depressed over this been fighting it for so long now...

I originally had a turbine system. I spent like $2500+ with that setup thinking that was the way to go and eliminate all the headaches of getting air in the lines etc. I thought that the turbine was the problem so I invested into an air compressor setup. I built a copper water drop system that goes to a DevilBiss QC3 filter. I spent about $1000+ on this air compressor setup with filters.

When I clear it lays down beautiful, no fisheyes etc. Just at that 2 hour mark the pinholes start showing up.

When I use a different brand clear coat it completes dies back. Looks absolutely perfect after I am done clearing, but cures with total loss of gloss at shown in the pictures. With SPI Production clear coat, it cures and looks beautiful, it just has the faint pinholes everywhere.

I lay down a canvas floor covering where I paint. I've actually tried it dry as well as soaking the canvas in water and laying it down damp hoping to keep dust down. Results were the same. I thought the paint booth exhaust fan was the problem. I ran that while painting and immediately shut it off. Still same results.

Attached is some photos of my setup and what I got going on.

If I wetsand the with 1500,3000 to 8000 I can remove all the pinholes. Its just alot of extra labor but thats what I have been doing...

I just don't know what else to test at this point. The only thing I can think of left to change is heating the clearcoat hoping it will make it go on thinner?
 

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61 degrees is pretty darn cold to be spraying clear. Try raising the temperature to minimum 68-70 degrees. Raise the temp for several hours before you spray. Get it warmer in there and keep it warm for several hours before you spray. Make sure the clear is the same temp. No real need to warm it although warming it to 80 or so wouldn't hurt. Same thing for your activator and reducer. How are you mixing the Production clear? What is your ratio? Are you using SPI reducer?
 
ebaypdllc said:
I've been battling and battling this problem and I just cannot figure out how to resolve it. I did some more testing and trial and error scenario's but I feel like I am at the end now and now sure what else to try...

I am shooting the SPI Production Clearcoat with medium activator in a climate controlled 63/67 degree room when its winter time. I do (2) coats with a 30 minute flash time. I am only doing small parts painting.

Whenever I clear, about 1-2 hours into the curing cycle, tiny little pinhole dots are showing up which to me is solvents trapped. The stuff I paint is curing correctly and looks great, its maintaining gloss its just those every so faint pinholes consistently throughout the whole part.

I basecoated a part and left it sit for 2 weeks and I got a factory painted part and recleared that. Both parts cured exactly the same so that eliminated that its anything but the clear coating process. I switched to the SLOW activator thinking that was the problem and it cured exactly the same as the medium activator. I turned off the booth fan, and I also ran the booth fan while the parts cleared it made no difference.

I've tried another brands clearcoat which is a faster clear with 2 hour cure time. I used their Medium hardener and it completely dies back and its total loss of gloss. I tried using the SPI FAST hardener with the clear and this made the process worse it total dieback.

I just don't get what I am doing wrong. I am using a Iwata LP80 with 1.2 tip.

I have the Very Slow and Urethane retarder here that I haven't experimented with.

Last idea I have is that I store the clearcoat and reducer on a concrete surface floor. I thought maybe its getting cold and changing the viscosity of the clearcoat so that it flows thicker similar to engine oil? Should I try and warm up the clear before applying it? Or should I try an even longer flash time between coats of clear?
Click to expand...
What is pressure at your gun while spraying clear?
Do you reduce production?
Did you try to do not turn off fan as soon as overspray comes out(I know that Barry suggest that)?
Sprayed production with medium and fast hardener the whole winter at 55/60 temp without any problem
 
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Your problem seems very same as mine for last 2 years, which I finally figured out. Clear coat used to boil, solvent pop, die back after 1-2 hours. However, I can't see well on your pictures if that is boiling/dieback or air contamination
 
Pay attention to what Barry said in his reply. Water in your lines. Looking at your pics that's a mighty small air compressor to be trying to spray with. I imagine it's working to death trying to keep up. Which means it is putting out hot air. I see you have a desiccant dryer but nothing in front of it. Your desiccant dryer may not be getting all the water vapor due to not having a water coalescer filter in front of it. Dessicant filter like that needs a water coalescer and oil coalescer filter in front of it. Like Texas stated above try one of those desiccant snakes which attach to your gun. See how quickly it turns pink. Spray something and test it.
Setup like you have you need to constantly being draining those ball valves as well.
This is what I'm referring to.
https://www.summitracing.com/parts/dvr-130502?seid=srese1&gclid=Cj0KCQiAtOjyBRC0ARIsAIpJyGPyktaTGgBtuzZaxBnW7gW9SX5TjyEjxzrCqFm7ChL4vEcEjydxA1oaAtgrEALw_wcB

One more thing are you force drying the parts or allowing them to air dry?
 
another thing this could be is air entrapment. this usually happens when you spray clear that is too thick. i have never shot the production clear so i dont know how thick the product is especially when its cold. i know the 2.1 universal will get a little. it needs 10% reducer added if the clear is just a little cold. you will see air entrapment when you clear black or a dark color. the clear will spray almost with a cloudiness then it will clear up as it sits. the cloudiness is micro air bubbles which eventually make it to the surface.
 
I mix the production clear 4:1 with no reducer. I am using the Iwata LPH80 and I spray at 20 psi which gives me a really nice finish. The air compressor I have is small, but I only paint small items so it rarely runs. I always check my copper tubing and I do get some water in the traps but nothing horrible. The dessicant system the QC30 still shows blue and no humidity in the line.

The turbine system I had I was getting craters in the clearcoat so I did away with it. The turbine outlet was around 130F and when it was being used in my colder area 60-65 I think it was condensing vapors. That also would dieback, along with craters.

With the LPH80 1.2 tip the finish goes on nice, no craters nothing. Just the dreaded pinholes.

I'm going to try and clear something again tonight. This time around i'm going to warm up the clearcoat. I am also going to try and use a different spray gun see if that makes any difference. I have a turbine gun here that can be converted to work with an air compressor.
 
Here is the Apollo 7500GTO "clearcoat" gun I bought that was expensive awile back...

I read that you can screw a male compressor fitting into the turbine fitting. Getting desperate...ughhh
 

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Re-reading everything I also have to ask how were things in whatever your summertime temps were? I do seem to remember bubbles & dieback were a prime issue you had with the turbine, which would not have had any oil contamination & should produce dry air. I know you didn't get any modern turbine experienced help here being others having such a bad taste in their mouth from the early systems, but from what I've seen of my Titan 6 stage, which is not automotive marketed, I think it should work fine if all is correct.
Only time I ever had dieback of clear was hammering on finish too thick. Got air entrapment from too thick also, get it with waterborne acrylic at work if I over do it as well. Cold product stored on floor will be thicker & more likely to entrap air. Air temp is really colder than ideal also.

I know this has been discouraging for you, but believe me many of us have done less than perfect with lesser quality materials at some previous point in time & not had your issues, so this is fixable. Do some sampling with warming material, checking with IR gun, checking painted surface with IR gun. Spray some thinner with longer flash time & spray some thick.
See what happens. Keep your chin up.;)
Don't think the Apollo gun is meant for compressed air. I'd retry with it also. Just cuz the gun makes heat doesn't mean it will compensate for cold liquid.
 
I would not recommend change guns or going to turbine or changing the clear coat brand. You just adding more variables which can cause problems. Your trouble is in rather your gun adjustement or your air supply or air contamination.i dm you what to try with gun, and guys here told you about to try with other two causes
 
I'm wondering if serjik911 is onto something.... The turbine I used sprayed the clearcoat beautiful at 7.5 PSI. The Iwata LPH80 says its supposed to spray at 7-14PSI inlet. I spray the clear at 20. I'm going to up the PSI to 27-28 perhaps maybe thats what is happening is the coating is just too thick? Especially being cold and its trapping solvents?

To be honest, I spent so much time and money trying/building new setups that I took mental breaks due to the frustrations. I never got a chance during spring/summer to try its always winter. This has been battling me for so long now frustration level through the roof.
 
Just did another test...(2) coats of Production at 28 PSI instead of the 20 PSI with the Iwata LPH80 1.2 This is straight off the gun...Now the waiting game ughhh


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