WIP - painting & gloss coverage issues

[MA Cooke]

I've been working in Tamiya's 1/48 F-14D (building as a B, VF-143 Dog 100 circa 2002 - 2003) for almost two years now. I had recurring paint coverage issues on this one, as I've had for over 20 years of building.

 

With the darker two TPS colors (36320 and 35237), as well as with clear gloss coats, I'm getting a rough surface in several spots. The greys are Mr. Color lacquers, thinned with MlT, and I've been.putting down a light after coat of MLT atop the paint. Most notably I'm getting pebbling between the vertical strikes as shown, but also at sharp angles near the fuselage. (I'm thinning the paint by about 2:1 thinner.)

 

As for the gloss coats, I started with Mr. COLOR # 46, thinned about 3:2 thinner to paint, and spraying about 20 psi dynamic.

 

I tried Tamiya X-22 clear gloss, again about 3:2 thinner (MLT again), and still getting the pebbling.

 

Any thoughts or suggestions are appreciated.

Edited January 22, 2023 by MA Cooke
Wording

[Janissary]

My guess is airbrush paint circulation around concave areas (vortices) is causing the paint to dry before hitting the surface. 20psi trigger down sounds too much to me. At least in my case, my static pressure (trigger up) is around 14psi tops, then down to 10-11 when painting. Your thinner ratios sound reasonable as long as in all those ratios the thinner is more than the paint (which I think is what you mean).

[MA Cooke]

13 minutes ago, Janissary said:

My guess is airbrush paint circulation around concave areas (vortices) is causing the paint to dry before hitting the surface. 20psi trigger down sounds too much to me. At least in my case, my static pressure (trigger up) is around 14psi tops, then down to 10-11 when painting. Your thinner ratios sound reasonable as long as in all those ratios the thinner is more than the paint (which I think is what you mean).

Correct, more thinner than paint. Maybe I didn't mention that when I'm painting (plants, not clear coat) the gage shows 20 psi trigger up, and 15 psi dynamic. Maybe I should back down to 12 or 13 dynamic?

[Janissary]

yes dialing it down may help, at least that would be my first step. Also, keeping a ~45deg spray angle to the surface may help a bit rather than coming down perpendicularly if that is a factor. Finally, I find rubbing the surface down with a dry cotton t-shirt after the paint has cured helps knock down any of that 'dusty' finish. I do this before any clear coat regardless of whether I see a pebbly paint finish or not. 

[MA Cooke]

37 minutes ago, Janissary said:

yes dialing it down may help, at least that would be my first step. Also, keeping a ~45deg spray angle to the surface may help a bit rather than coming down perpendicularly if that is a factor. Finally, I find rubbing the surface down with a dry cotton t-shirt after the paint has cured helps knock down any of that 'dusty' finish. I do this before any clear coat regardless of whether I see a pebbly paint finish or not. 

Thanks for the tip - I dialed down my dynamic to about 11 - 12 psi, and that worked - much better results!

 

As far as rubbing the surface down, I "usually" do buff out any roughness, but for whatever reason I didn't this time. I often use just plain notebook paper, or a clean fabric cloth.