I have notice on occasion that when airbrushing, that I can get a grainy finish to the paintwork. This doesn’t seem to be connected to any particular coulour, it just seems to be random, possibly the paint being to dry by the time it hits.
It has crossed my mind that I should maybe be laying down a thicker coat, but I dont want to get into the “run” scenario.
I am using fresh Tamiya acrylics, thinned as reccomended with their own thinner, any suggestions?
Thanks.
Possible reasons-
Pressure too high
Distance from airbrush to surface too great
Putting down too thin a coat
Are you using gloss or flat paints? For glossy finishes it is a game of brinksmanship. You need to build up paint to the point just before it runs. How do you know that point? Practice. Glossy finishes are harder than flats just because of your exact concern. Practice and experience are the keys.
This time around its with gloss, but it has happened before with matt & black seems to be the worst coulor for it.
I started about 20PSI (gravity brush), & have dialed this down to about 12PSI or so, but it makes no difference. I am spraying at about 2 inches, so it looks like I may be laying down to thin a coat.
Thanks.
Or the paint is not thinned enough. Maybe try adding some more thinner? Good luck
Pawel
Sounds like you’re doing it right. Do try the heavier coat of paint and let us know.
How hot is it in your spray area? That could also be a part of the problem.
I watching closely. I’ve had the same problem many times, always with flats. Usually around wing roots where the paint can swirl around. I’ve tried more thinner, less thinner, more and less pressure, shooting at different angles. Nothing seems to fix it and I end up sanding the paint in that area smooth and moving on.
I think the paint is drying before it gets to the surface myself but I havent figured out exactly how to prevent it yet. More thinner and it runs. Less thinner and I have to crank the pressure to blow it… I’m beginning to think trying a different thinner that evaporates slower may be a fix.
Try a retarder in the paint. That will slow the drying time down, ans smooth out the finish.
-Jim
HK, this is the very area it has happened to me on several occasions.
Jim HCH - tamiya thinner already has retarder in it, bo you think more would help?
And I’m using enamels. What retards those?
Since Tamiya thinner already contains a retarder, adding more may be unwise. Instead:
Raise the relative humidity to 50-60%.
Drop your pressure to 10psi.
Thin to the consistency of 2% milk.
You can also add a small amount of distilled water to the paint as a cosolvent. Since water evaporates more slowly than isopropyl alcohol (the primary solvent in Tamiya thinner) it will slow drying time.
The problem at the wing roots is caused by paint globules bouncing off the fuselage and wing before they settle on the opposite surface (yes, they can do this). The solution is to drop your pressure, get closer if necessary or possible, and spray that area from a direction parallel to the angle or curve between the fuselage and wing.
Might want to check the tip of your needle too and make sure you don’t have a burr. Doesn’t take much. Drag it across a fingernail and if it scratches, polish it.
hkshooter, Floquil sells a retarder. Haven’t bought any for a couple years, I guess they still do.
Tony