I use Tamiya, GSI, and AK real colors. Every now and then this happens and I don’t know why. I’ll get what I think is just the perfect dilution of paint. And I’ll be painting for awhile and all the sudden the paint goes wet. I guess what I mean by that is that all of a sudden it seems like the mix is way thinner than it was and I can start having the problems one has with a too thin dilution and too much pressure. I usually just add a little more paint in, remix, and can get back to where I was, but I’m wondering if there is something different I could do to keep this from happening to begin with.
Sounds like there is moisture in the line that gets blown onto the surface. An in line moisture trap is the best solution short of investing in a CO2 tank setup. Having a compressor with a tank also helps as the water is heavier than the air and settles on the bottom of the tank. You will still need to drain the tank periodically and also still need to have in in line moisture trap. Good luck.
Either it’s moisture in the compressor tank like @Armorsmith said or your paint is settling in the paint cup.
I experience this if I paint too long. As @barnslayer states, I’m fairly certain it’s the paint settling out from the thinner. If I notice it happen I’ll bubble the color cup by covering the nozzle and letting air flow into the color cup. It usually solves the issue
don’t bubble the cup with too much air pressure,
I got lucky since I was wearing glasses,
took a while to wash my hair though …
It definitely requires a light touch, and I usually do it away from the kit just incase
my compressor has a moisture trap…
I almost guarantee it’s paint settling then. I experience it most often with mr surfacer as I thin it more for priming than normal paint
Also as @Armorsmith mentioned you should get a second moisture trap. This would go between the compressor and the airbrush in the airbrush hose.
Interesting. I understand the idea of the paint pigments settling to the bottom of your paint cup. Spraying would then spray the heavier pigmented portion first and then the remaining thinner, less pigmented portion would spray becoming wetter as you said.
I have never experienced this however while painting. I have, if the paint has set for a long time but not during a paint session. Maybe it has and I am just clueless of it. I tend to run a heavier paint to thinner ratio. I am a two coat guy not a 4 coat guy.
If it were water, I understand that as you paint, condensation builds up in the line until it finally spatters out onto the painting surface. Mine did that prior to me converting to CO2. I never experienced a wetting effect of the paint itself. What will happen is as you are painting a droplet of water will spray out along with the air. Paint will immediately cover it creating a drop of water sealed in by the paint and the grumbles begin. It only happens to me when I am trying to achieve a perfect smooth gloss paint finish…
So the first case sounds more practical based on your description. I then would look at why things are separating so fast. Is your paint and thinner from the same brand? If not they may not be mixing well and quickly separate. Does it do this with other colors? Do all three brands do this?
If the paint is precipitating out of the thinner then I would suggest that there is too great a thinner to paint ratio. I would try increasing the amount of paint or reducing the amount of thinner. Good Luck.
Maybe the thinner isn’t very compatible with the paint?