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Stumped On A Clear Coat Defect

SPR

New Member
#1
Hi all. I hope this is allowed here. I have a commercial painting business but I restore pinball machines in my spare time. A function of that is clearcoating the new playfields (the wood surfaces the balls travel on). At any rate, I’m by no means a pro in the automotive world but I am proficient in the commercial architectural painting world. I know there are significant differences but I do know the value of proper prep techniques, equipment setup and usage etc.

At any rate, I am running into an issue clear coating a recent playfield. I have flip flopped between my issue being contamination, solvent pop or air entrapment. The new playfield comes with a shoddy clear coat already. The product is unknown. My process/equipment leading up to the pictures

-Surface sanded flat with 3m blue 800grit
-Surface blown clean the wiped with sontara cleaning cloths and SW FT200 surface cleaner.
-Allow to dry and repeat cleaning steps a second time.
-Gun is a Tekna ProLite with 1.3 fluid tip (I have a 1.2 tip) and te20 cap. I started with fluid at 3 full turns as recommended by SW. I have since reduced to 2 full turns. Fan wide open. Air at 22psi with trigger pulled.
-Material used is SW CC200, UH80 hardener US4 reducer at 4:1:15%(this last sprayout was closer to 20% hoping for better flow)
-Environment was 66 degrees 37% humidity.
-
Sprayed in a homebuilt dedicated spraybooth with filter floss on intake and sticky filters exhausting into booth. Wall exhaust fan.
-air is filtered trough air trap, black pipe cooler, motor guard filter and then a DeVilbiss decessant filter. The air is the plumbed to the booth and run through a dryaire 3 stage cleaner and motorguard activated carbon filter to remove and remain oil aerosols.

The pictures of the playfield show the bottom half sanded using 3m trizac 1500 dry sanded on a d/a.
Upper half untouched after spraying. It payed like glass other than the blemishes. You can see one before sanding and one after sanding. I’m still leaning toward solvent pop due to the near perfect circles left behind after hitting it with a sander. Im at a loss and I would greatly appreciate the expertise of the members here to suggest fixes on what I’m doing wrong. I know this is an spi forum and I plan to switch to their clears once I use up the sw product. Thanks in advance.

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Last edited:

Barry

Paint Fanatic
Staff member
#3
Well this is a tough one.
The air entrapment is not even a consideration.

Looking at the pictures (makes it hard to really tell) my first thought was the way they are spread out its C02 gassing BUT then I see you have a desiccant system and if it maintained right there is no way vapors are coming through the hose.
Now with a 1.3 if you wet the floor it still could happen but it would not show up for 60 mins to 4 days after the last coat.

IF it showed up on second or third coat within a minute or so of spraying than it is solvent pop.
It just looks to sporadic to me to be pop but again pictures are tough to tell.
 

SPR

New Member
#5
Thanks for replying, Barry. I was hoping you would. Also, thank you for the compliment. I invested a lot to get a setup that allowed my to produce high end results. Aside from the defect I’m getting, the surface is glass like with no peel. At any rate, the defects show up seconds after being laid down. Definitely not hours or days. It’s happening so quickly I originally thought I was getting trashin the coating. It’s only when I sanded it that I saw nearly perfect circles that lead me away from thinking trash. The desiccant is fresh out of a sealed graco bulk container.
Operating on the guess of solvent pop, what suggestions do you have. I am already below the manufactures recommended gun setup on gun fluid adjustment of 2 turns versus the recommended 3 turns/full open. My fear is I’m going to throttle the material back for far it starts affecting the pattern. I have played with the reducer (concentration as well as temp) trying to extend the flash time to try stop entrapping solvent gasses. I’m pulling my hair out (and I’m bald) trying to get this right. I’m so close but so far away. I’ll sand the rest of the playfield and post some full length shots to better show the affected areas.

Thanks again for the reply.
 

Barry

Paint Fanatic
Staff member
#6
Now we're getting somewhere.
I trust you did not use wax and grease remover on the fresh base.
If happened on first coat of clear you applied clear to soon. More true with your systems then others.
If it did not happen until 2nd or 3 coat than that coat was applied to soon.
 

Barry

Paint Fanatic
Staff member
#7
My concern is it looked like dirt you said.

That can be iso clumping cause by water and high humidity and a 1.3
Did you wet floor.
 

Barry

Paint Fanatic
Staff member
#8
HOW TO TELL if ISO clumping.
Lets say we are doing a large hood, I'm standing on the driver side and starting at fender I lay my first coat of clear stopping in the center of hood, it looks perfect!
I walk too other side and start in center and as i get just about to the fender on passenger side I see little specks of dirt pop up on the drivers side.
Dirt does not pop up from under the clear, if you clear over dirt you see it, if dirt comes from masking paper it sets on top of clear.
This dirt can be gray, white or black depending on water content
 

SPR

New Member
#9
No wax/grease remover over base. The item I’m coating is silk screened wood with ink and then shot with production clear. They do such a crummy job clear coating, I sand that production clear flat , wipe it clean clean with a SW surface cleaner made for the line of coatings I’m using. I was wiping it clean with MEK but switched to the sw product (smells like mek anyway) to see if that was causing my issue but it didn’t change anything. I did not wet the floor, I have booth floor liner by 3m installed on the floor. The humidity was around 40% at the time of application. I’ll add one more component to the puzzle. I too was worried about contamination so I spray a test panel with the SW coating and another area on that panel I sprayed a section with a rattle can of the USC 2pac 2k glamour. I effectively took my gun/air delivery and booth/dirt contamination out of the equation by using a rattle can. The SW coating on the panel defected like in the pictures, the rattle can was free of the round circle defects. It did have some fuzzies/dirt but when I sanded it out, it didn’t leave behind those circular defects.
 

Barry

Paint Fanatic
Staff member
#10
Your not using the 3m pps cups are you or have an internal strainer in side the gun? If you do dump all.
I would look at slower activator or a shot of retarder per mixed quart of clear on last coat.
Or stretch time between your coats of clear.
 

SPR

New Member
#11
I’m not using pps/disposable but I do have a filter in the gun between the cup. I have the reducer for medium temp and hot temp. I’ll bump from cold to medium and dump the gun filter. I’ll die if it’s a damn $1 filter causing my problem.
 

Barry

Paint Fanatic
Staff member
#12
With a higher solid clear it is a real problem, it even will mess up some base coats.
Never ever use them.
Most industrial and production clears are so low in solids the filters don't matter, better products it does matter.
 

SPR

New Member
#13
At this point I’m willing to try anything. I’ve applied and sanded off dang near a gallon of clear. I will say the CC200 is supposed to beSW’s top of the line air bake clear. Who knows. It’s worth a shot to see how it works. I’ll post a follow up this weekend. While I have you, what clear do you recommend from spi? I’m looking for a high gloss glamour clear that’s not brittle since it will have a pinball bearing on it.
 

Barry

Paint Fanatic
Staff member
#14
He's using cc200 and wants a spi product? If so euro for sure.
__----------------------

This is the answer is from a big s+w
Jobber that has sold spi for 18 to 20 years.
 
#15
That CC200 is a new extreme speed clear and might be the source of the trouble. If I was using S-W or had a bunch of UH80 to use up, I'd get the older fast clear instead, CC931. S-W actually had (has?) a process where CC931 and CC950 can be blended depending on job size and how you want it to look. I got some very good results with a 50/50 blend of the two, but ultimately SPI is better clear and a much better value.
 

SPR

New Member
#16
That CC200 is a new extreme speed clear and might be the source of the trouble. If I was using S-W or had a bunch of UH80 to use up, I'd get the older fast clear instead, CC931. S-W actually had (has?) a process where CC931 and CC950 can be blended depending on job size and how you want it to look. I got some very good results with a 50/50 blend of the two, but ultimately SPI is better clear and a much better value.
I was using the fc line of clears but their gloss levels weren’t “wet” enough so I switched to the cc200. It is a nice clear, clear that is wet but I’m have a heck of a time. It probably is the clear considering a rattle can of 2pac laid down without blemishes. I concur, I intend on switching to spi clear going forward but I have 1/2 a gallon of the cc200 so I’m hoping to sort it out. In the end, it’s made me a better applicator by forcing me to refine my process but frustrating because I know it’s something simple gripping me up.
 

Barry

Paint Fanatic
Staff member
#18
Check wall regulator air at wall should be min of 125, mine at home is 158. This is scfm related more than air related.
Air at gun with 1.3 24 to 26.
With 1.4 28 to 30 with trigger pulled.
 

SPR

New Member
#19
Check wall regulator air at wall should be min of 125, mine at home is 158. Scfm.
Air at gun with 1.3 24 to 26.
With 1.4 28 to 30 with trigger pulled.
I have my system set at 100psi. My compressor only reaches 150psi and most of the filters/line are only rated to 125psi. With the trigger pulled on this last shoot is was at 22psi at the gun. It seemed my results were worse at the higher gun psi.
 

Barry

Paint Fanatic
Staff member
#20
I have my system set at 100psi. My compressor only reaches 150psi and most of the filters/line are only rated to 125psi. With the trigger pulled on this last shoot is was at 22psi at the gun. It seemed my results were worse at the higher gun psi.
With a 1.3 the higher air pressure would cause it to dry faster.
If 100 is best we can do, it is still way better than say 70 or 80 at wall, as the SCFM breaks up the higher solid clears and makes your metallic lay better with less effort.
The test on how much paint can be saved with higher pressure at wall was done with 140, so not sure if 100 lbs at wall is saving any money.
 
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