AB causing a Pebbling Effect

starmanmm · Post by **starmanmm** » Mon Oct 11, 2010 12:12 pm

I've finally gotten around to painting the 22" E and because of the size.... I went for my Wren B than my Iwata CR for coverage.

The paint is Gunze Sangyo thinned with 91% alcohol with the compressor set at 20 psi. I was spraying at around 4 - 6" away.

But the finish spray is looking like the surface is pebbled?

What causes this effect?

Ziz · Post by **Ziz** » Mon Oct 11, 2010 1:04 pm

Sometimes the pigment isn't fully mixed and melted into the paint liquid, so thinning the paint for airbrushing only compounds the problem. Strain the paint thru a piece of nylon panty hose.

rpauly · Post by **rpauly** » Mon Oct 11, 2010 1:15 pm

Dial your air pressure back to 10-12 pounds, or get an inch or two closer. The paint's already drying by the time it hits the model.

Lonewolf · Post by **Lonewolf** » Mon Oct 11, 2010 7:17 pm

rpauly wrote:Dial your air pressure back to 10-12 pounds, or get an inch or two closer. The paint's already drying by the time it hits the model.

That was my first thought as well. The higher PSI is causing the paint to dry in-flight between the nozzle of the airbrush and the surface of the kit.

starmanmm · Post by **starmanmm** » Mon Oct 11, 2010 8:10 pm

I was under the understanding that you would shoot are high psi for the coverage... but I am thinking that the 91% is causing the paint to dry too fast.

ExarKun77 · Post by **ExarKun77** » Tue Oct 12, 2010 2:28 am

"91%" is not a mix ratio, it's the concentration of the alcohol.

Mark Yungblut · Post by **Mark Yungblut** » Tue Oct 12, 2010 3:41 pm

What is the mix ratio? and yeah your paint is drying before it hits the surface. Add just a little more paint to the mix and move closer 15psi should be about right. I suggest testing before each session. I have bunches of scrap that I practice on to make sure that I have everything tuned correctly prior to application.

Cheers,

Mark

starmanmm · Post by **starmanmm** » Tue Oct 12, 2010 8:44 pm

I know that 91% is the alcohol... what I was saying is that maybe too much alcohol in the paint is causing the issue. Alcohol speeds up the drying time... so I'm guessing that the purer the alcohol... the faster it maybe causing the paint to dry.

Mark Yungblut · Post by **Mark Yungblut** » Tue Oct 12, 2010 10:26 pm

My personal rule of thumb is 1/3 paint to 2/3s thinner is the MAX thinning. Typically I use a 50/ 50 unless it is an airbrush color like many of the testors enamels and the metalizers.