Bubbles in clear coat

C

C Welsby

New Member
Hey Guys,

I have been using the universal clear coat over some artwork.

The artwork is airbrushed using acrylic paint and then finished with the clear to protect it and give it a glass finish.

I have been having an issue with bubbles appearing at the surface about an hour after the last coat, tried everything I can think but still having the issue. Sometimes it comes out great, other times I get the issue. (see photo) Looks worse in the photo but obviously that's not supposed to happen.

IMG_1560.PNG


I am using a sata 5000 rp 1.4
Universal clear with slow activator
I have a 1 micron and 0.1 micron moisture trap followed by a desiccant dryer. Even a mini desiccant dryer before the gun.
I am spraying at 25psi (90 at the wall), it lays down smooth, I try and do nice thin coats, never runs.
I have tried turning fan off between coats as suspected it might be drying top layer too fast.

Really can't figure out why sometimes this happens because I have been taking care to replicate same technique.

Any suggestions would be greatly appreciated.
 
Thank you for the suggestions,

Yup it could be moisture but I've done my best to get dry air. Got a mini desiccant filter at the gun so I could see if any moisture was making it that far and so far the beads are still blue so I am somewhat sure its not moisture. I am using airbrush paint, had the same issue even on paint that has been sat drying for weeks before clear coat so I am fairly certain it's not that.

Barry, if it is wrinkle is that me laying it on too thick?

One other thing is that the product has been sat on concrete floor for weeks, could the cold cause this?

Thank you all!
 
C Welsby said:
Thank you for the suggestions,

Yup it could be moisture but I've done my best to get dry air. Got a mini desiccant filter at the gun so I could see if any moisture was making it that far and so far the beads are still blue so I am somewhat sure its not moisture. I am using airbrush paint, had the same issue even on paint that has been sat drying for weeks before clear coat so I am fairly certain it's not that.

Barry, if it is wrinkle is that me laying it on too thick?

One other thing is that the product has been sat on concrete floor for weeks, could the cold cause this?

Thank you all!
Click to expand...

How long after you finished the base/airbrush work before you cleared? How many coats? How long between coats? Looking at that pic that is really bad dieback or gross amounts of water in your air. Being that you can't detect any water in your lines, it is probably something you are doing in regards to application.

No it won't wrinkle from laying it on thick. It can dieback though. From the pic it doesn't look thick at all. Looks good other than the dieback. It can wrinkle if solvents in the clear attack the basecoat. Normally this is rare but a possibility seeing you are using unknown paint.

As for concrete floor and cold, unlikely unless you sprayed it in relatively cold temps. What temps did you spray at?
 
It's the beginning of;
Minor moisture.
Minor wrinkling.
Minor solvent pop.

What it looks like to me is when a shop uses my clear the first time, and they think it's a misprint to turn the fan off on the last coat.
My guess is the beginning of solvent pop.
2000 wet and buff.

By the way, the water trap you have on your gun is useless, take off, give it to someone you don't like.
Years ago, I bought a case of every one sold and tested.
 
I generally give at least 48hrs after the airbrushing before I add clear. Sometimes it has been weeks before I get around to adding clear.

I do 5 coats with a 30min flash between. Always turn fan off once overspray has gone. I then sand and flow coat usually the next day. The issue has happened both on first layer and also on flow coat so I am fairly certain its not caused by the airbrush paint. Especially as it has turned out perfectly on occasion. I have also tried only doing 3 coats and same issue. I am not totally sure but I would say my paint room is around 65-75.

After doing more reading on here yesterday I see Barry and others saying they set their sata 5000 rp to 3/4 - 1.25 turns out. I have been doing 2.5 turns out which may well be the issue. Going to do a test today and see if that makes the issue go away.

Thanks for the pointer on the filter at the gun. Thats good to know. I added one more to try and rule out moisture as the cause of the issue but I will give it to someone I don't like. ;) Total newb to all this, really appreciate the help!

Thank you
 
C Welsby said:
Barry and others saying they set their sata 5000 rp to 3/4 - 1.25 turns out.
Click to expand...
Don't know that I've ever seen 3/4's of a turn recommended. That's really tight. I've used a 5000 RP for a number of years now and I've found that full fan, 1.5 turns out and 75% overlap works very well on UV and other clears. Try that setting. Move fairly quick. 2.5 turns out is definitely hosing it on. As you are spraying look for the clear "filling in". You want it to fill in and no more than that. Tighter overlap means you can spray faster and not have to hose it on.
 
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