Quick Question About Airbrushes

[GU-11]

Finally set up my Tamiya Spray Works basic compressor and airbrush. I tested it out with diluted food coloring just now, and the airbrush keeps spraying air even when I'm not pressing the trigger. I inserted the needle as deep as it would go without forcing it, and it decreased the airflow, but there's still a little air shooting from it. Or maybe I should use a little more force and insert the needle a little deeper?

Is this normal for airbrushes?

I thought only double-action airbrushes sprayed air when the trigger isn't pulled? The one included with my compressor set is a single-action one.

I'd appreciate any advice.

[David Hingtgen]

Nope, something's wrong, don't force the needle. I'll let more airbrush-experienced members trouble-shoot.

[anime52k8]

I thought only double-action airbrushes sprayed air when the trigger isn't pulled? The one included with my compressor set is a single-action one.

I'd appreciate any advice.

Regardless of whether you have a single or double action airbrush, if it's working properly it shouldn't allow any airflow out if you're not touching the controls. Also, the function of the needle is to regulate paint flow/paint spray pattern so needle depth will not effect air flow at all From the sound of it, there's something wrong with the valve; either it's not closing properly when you take your finger off the trigger or it's not getting a proper seal.

[GU-11]

Thanks for the replies.

Is there any way I can fix this myself, i.e. disassemble the airbrush and check if something's loose?

The Tamiya manual said to push in the needle because if this happens, there is a gap between the needle and nozzle. I did that, but it didn't solve the problem.

UPDATE:

Apparently the basic airbrush that came with the compressor might not even have a valve, although I'm just guessing here.

In the manual, it says that you have to remove the stop-valves of aibrushes if you want to use it with this compressor. It specifically says, "If brush airflow stops, compressor breaks."

Am I right in assuming the airbrush included with it doesn't have a valve, and it's normal that the airflow continues even when the trigger isn't pulled?

Edited September 27, 2012 by GU-11

[Jefuemon]

It's actually OK. Is any paint coming out when you're not depressing the trigger? Then there's no problem. I've got the Tamiya REVO with a HG-II double-action brush, and yes a little air comes out when the compressor is on. As there's no tank, if you totally stop the air flow from the compressor it will break.

However, no paint comes out unless I pull back on the trigger. If you've got no paint coming out unless you want it to, there's no problem.

[GU-11]

It's actually OK. Is any paint coming out when you're not depressing the trigger? Then there's no problem. I've got the Tamiya REVO with a HG-II double-action brush, and yes a little air comes out when the compressor is on. As there's no tank, if you totally stop the air flow from the compressor it will break.

However, no paint comes out unless I pull back on the trigger. If you've got no paint coming out unless you want it to, there's no problem.

Glad to know it's actually normal!

It wasn't apparent when I sprayed the food coloring onto the cardboard (red on brown cardboard--stupid choice), but when I aimed the nozzle at the back of my palm without pulling the trigger, I felt a very thin vapor mist.

[Jefuemon]

This is my set-up, by the way.

How's your's working out?

Oh, and the brush is an HG-III, not II.

Edited September 29, 2012 by Jefuemon

[GU-11]

This is my set-up, by the way.

How's your's working out?

Oh, and the brush is an HG-III, not II.

Nice!

I ran out of food coloring just as I was about to test it again today, so I'll only be able to find out later if the paint's leaking, after I get some more. I'm really kind of worried about it right now. Maybe I'll just try filling the cup with water and aim the nozzle on newspaper, and see if any water sprays onto the newspaper.

Okay, I just tested with some water, and it works just fine, thankfully. No water sprayed out until I squeezed the trigger.

As for airbrushes, I'm still using the one that came with the compressor. I plan on eventually upgrading to the metal HG trigger-type airbrush. I heard that the traditional "pen-type" airbrushes are hard on the fingers, and controlling the amount of paint is difficult, especially for those new to airbrushing. Is this true?

In any case, I'm not sure if I can use double-action airbrushes on the basic compressor, seeing as it can't be used with stop-valves. Can it?

BTW, is it possible to do post or pre shading using a single-action airbrush?

Edited September 29, 2012 by GU-11

[Jefuemon]

Mine's a double action, and it works no problem. I did have to take the stop valve out of the brush (it even shows you how to do that in the instructions if you're using it to a Tamiya compressor). Of course, I can't control the amount of air flow, but I can control the amount of paint. The farther back I pull on the trigger, the more paint comes out. See that big screw at the back of the brush? I can also use that to adjust how far back I can pull the trigger, in case I need extra help in doing fine line work by forcing me to not pull back all the way.

I've always uses the pen type, and never had any finger trouble.

I've never done pre or post shading, so I can't help you out there. Sorry!

[GU-11]

Thanks for the info, Jefuemon!

I just found out that the basic airbrush is technically "pseudo" double-action, as you can adjust the amount of paint using a slide on top of the airbrush, something they call a "needle stopper," except that the airflow is constant. The description on the box says it can handle cammo effects and fine lines, so I guess it'll suffice until my skills have advanced enough.

But seeing as I don't usually build "real-life" tanks and jets, the basic airbrush is probably all I'll ever need.

BTW, how do you deal with the dry-tip problem on the airbrush, and keeping the paint in the cup from drying while you wait to apply the second coat? I heard it's a problem with acrylics, which is the only kind of paint I can get my hands on.

Edited September 30, 2012 by GU-11

[Jefuemon]

Second coat?

Another thing I've never really had to do. That's either because of my paint selection (Gunze Mr. Color), or I myself am just happy with a single coat. Mr. Color dries really fast, so on the times I've needed to do a little extra, usually the first piece I've painted is dry by the time I finish off the last piece, so I just start again at the beginning.

I also never clear-coat, too. Am I some sort of heretical builder?

Cool!!

[GU-11]

Heretic! Hath thou no shame?!

Wait, are you seriously telling me, you only spray one coat of paint without clear coating? Please tell me you at least prime them before you give me a heart attack.

Dare I ask if you bother to thin your paints?

Unfortunately for me, Tamiya acrylic paint is all I can find in my neck of the woods, and most every bit of advice I've scrounged from Google says to thin it 1:1 and spray three thin coats. The Spray Work manual, though, recommends spraying straight from the bottle without dilution.

Wish I could find some Mr. Color paints here. Most if not all the model kit manuals use Gunze paints in their color guides (except Tamiya model kits, I guess), and it's pretty hard trying to match the colors with Tamiya paints.

[Jefuemon]

Yes, I do prime. I'm not that much of a heretic! Of course I thin my paints, too. About 50:50. I can really tell when I don't thin enough, because my paint will get clogged up in the brush, and spray real chunky. When that happens, I've found that back-blowing clears it out pretty well. Just cover the end of your brush real tight with a finger, and pull the trigger. Air has no were to go except out the paint cup, and that tends to clear out the chunky bits temporarily. Cover your paint cup with a tissue if you try this! Unless you like have uncontrolled spray all over the place. (yes, personal experience)

[GU-11]

Thanks for all the tips, man!

One more thing: how do you transfer the paint onto the airbrush's cup without spilling it? I've been using water and food coloring so far, so I can just pour it out of a plastic bottle. But with such a tiny amount of paint, I can't possibly use a bottle. The paint is thicker, too.

Or do you just mix it in the cup itself? I've heard this being done with bottom mounted cups, but I'm not sure if you can do that with gravity-feed cups.

[Jefuemon]

No, don't mix in a gravity feed cup. I tried that once with a small amount of paint, thinking it would work.

Refer back to my "paint not thinned enough" comment.

I've got a small bottle (maybe 50 ml max) that I do my mixing in. Mix it up well, then pour it into the cup on the brush.

[GU-11]

Okay, got it.

Now, to find something to paint!