More paint questions

Well, I just painted my Firebird model with Tamiya acrylics and was very displeased with the results. The paint turned out with heavy orange peel which will be difficult to remove during polishing. I may not have used the best spraying technique at the time (I guess I am certainly still learning to airbrush), but the next day I used a scrap body and practiced. I found that the most effective technique was to let out as little paint as possible while spraying very close to the model. However, even with this method, there was still roughness, and in fact the paint appeared flat rather than gloss. Heavier spraying, however, resulted in bad orange peel.

Is this problem caused by the fact that acrylics dry faster than enamels, and therefore don’t have time to flow smooth before they dry? I have painted many models with enamel and gotten spectacular results, with very smooth paint. However, I don’t want to use enamels any more because they take so long to dry and I can’t find compatible clear coat (the subject of a previous thread). That’s why I switched to acrylics, but they don’t seem to be working for me.

Is this the problem, or is it something else? And if it is the problem, what do I do about it? I want, obviously, to achieve a smooth paint job.

Do the Tamiya TS paints apply more smoothly? If so, are they safe to use in my plastic-bodied Testors Aztec airbrush? It had no warnings about using lacquers, and I’ve used Metalizers with success (with the “acrylic” nozzle), but I know that lacquers can be damaging to plastic. I don’t exactly have the money right now for a new, metal airbrush. Please help!

A refresh of the questions.


Paint roughness caused by faster drying time, or something else?
If the former, what to do about it?
TS paints flow smoother?
TS paints safe in Aztec plastic airbrush?
Thank you, I very much appreciate any help you can give (and hope my incessant questions aren’t too annoying).

Alex

TS paints will work fine through the airbrush and won't harm it in any way. They will definitely flow better once decanted from the spray can as they're already thinned for spraying, it is however just as possible to get orange peel with TS paints.

Paint roughness has nothing to with a faster drying time, so perhaps we should investigate other possible factors?

What did you thin the paint with and how much did you thin it?

The problem is very likely that you are either spraying at too high a pressure or that the paint is not thinned enough. These problems can be just as much an issue for laquers as acrylics.

This is perhaps simplified, but to get paint to go on smooth you want to apply it-

at the lowest pressure it reliably atomizes at,

as thinned as possible before it runs,

in light to medium, even but not wet coats.

OK, thanks for the help so far. I used a pressure of about 35 psi; I thought that higher was better (but of course I don't know very much about airbrushing, either). I just know that low low pressure will make for rough texture. What is a good pressure? I can adjust; I have a regulator/water trap. I thinned with X20A and used quite a bit; the paint was very thin but not to the point of running (as long as I applied thin coats).

Thanks

Alex

I just know that low low pressure will make for rough texture.

That there is a serious misconception.

Correctly thinned paint at a lower pressure is better, try to work in the 15 to 20 psi range and thin the paint correctly. Don't try compensating for incorrect thinning by increasing the spraying pressure.

I agree with you that acrylics tends to dry with more orange peel / roughness than enamels or lacquer. I experimented a bit with them to find a way to alleviate the problem, and this is what I found:

-Lower air pressure works better. I lowered from 20 to 15psi and the orange peel effect was less pronounced (but not eliminated). Try to use a high flow nozzle on you rairbrush if you can (0.5mm or higher, I tried with a 0.7mm and it was much better than with a 0.35mm).
-increase thinning ratio: Acrylics tend to be thicker than enamels and need more thinning to avoid powdery overspray and rough texture. I thin using Mr Color Thinner by Gunze / Mr hobby, as I found it sprays much better than with alcohol / Tamiya X20A thinner. I also add a drop or two of Mr Retarder Mild (Mr hobby product, too), it helps the paint flow out and level itself before setting (as a side note, Mr Color Leveling Thinner from Mr Hobby is just Mr Color thinner with Mr Retarder mild already mixed in).

Using both changes above will very noticeably improve your results, good luck!