Help with airbrushing body

That make sense - you're geting finer, dry-ish build up across the demarkation.

Try using a frame of some kind - like a wire coat hangar - to hold the car body by so you can spray the whole body in one session instead of sequentially. You may also need to spray a bit heavier coat (just slightly) so that the whole application remains wet until you have complete coverage, and/or thin your paint mixture more. Very critical with gloss finishes.

Rufus ranted on in the abyss about:

And said it was so.

Yeah. I probably ruined my finish. :(

I do spray it in one session. What I meant by sequentially is the way I spray it in one session. After one stroke i follow up on the next area with another stroke. I do use a hanger to hang my model.

This was my first weekend to use an airbrush. there are some parts that are curve shaped. if the airbrush blows on it it gets blown away. hehehe...

Well, I'm no help on airbrush-specific stuff but I paint car bodies with rattle cans. When I have a body with a complex contour (usually the front end) I spray that area first then spray to and fro up the bodysides and over the roof and decks.

Doing unibody vehicles usually involves doing the engine bay in the same colour as the exterior. What I do there is mask the exterior parts and paint the interior parts first. Later the hood is put in place, masking removed and the entire exterior gets colour-coated.

Bill Banaszak, MFE

Or cutting down the air pressure, if your compressor lets you to... (try spraying at 10-15 psi).

You didn't tell if you are using acrylic or enamel paint, however I found the best way to get a smooth glossy surface is to spray first a light mist, to give some tooth to the paint, wait some minutes and spray an heavier one, then wait still some 10-15 minutes and spray a "wet" one. All 3 coats should be sprayed within 30 minutes (acryl) or one hour (enamel). That way when you spray the second and third coat, the paint is dry to the touch but isn't fully cured so it's still a bit "sticky": this means you can spray a heavier coat with less risks of paint runs (and the paint softens a bit the underlying coats). The paint will self-level better and look more shiny.

In fact you should spray the final coat stopping just before it starts to run. You'll know when to stop only by experience, so you'd better test it before on a scrap model using different thinning ratios (always try on plastic, paper or cardboard don't give reliable results).

Hope this helps

Even if your workroom is the size of a basketball court, air resistance will cause the spray to slow down and stop. You need a spray booth with a strong fan to pull the fumes away from your work area.

If the room is really large, you *might* be able to make do with an ordinary household fan, positioning it to blow over your shoulder and past the model.

If you're using acrylic paints, part of the problem might be that the paint is drying too quickly; when the fine mist hits a recently sprayed area, the surface is already dry so the new particles just stick to the surface instead of being absorbed into it and leveling out. Try adding a bit of acrylic retarder or airbrush flow medium, which can be found at any good artist supply store.

It can probably be fixed. Just let it dry a few days, then wet-sand it, starting around 1000 or 1500 grit and working your way up. If you start sanding through the paint to the plastic, stop and paint it again.

You can find 1000+ sandpapers in stores that sell stuff for car repairs.

This could be a sign that your air pressure is too high. If the compressor has a pressure gauge, try dropping it down to around 15-20 psi. If there's no gauge, try loosening the pressure relief valve.

Yuri ranted on in the abyss about:

And said it was so.

Let me guess. You quoted that from Scale Auto Mag's "Automotive Modeling" book. ;)

Yeah. I did spray a fine mist to it. in fact, I used white because the plastic is naturally black. I used the white as a primer so I'll know what parts of the body wasn't painted. I'm using acrylic though.

I lay off for a week because the fumes are just intoxicating and the open space where I work has a random air pattern.

Wayne C. Morris ranted on in the abyss about:

Hmm... that would explain it then. You're probably right about the paint drying too soon. So if I thin it more it will slow down the drying process?

Actually I have a dozen in my toolshed. :)

Sadly, my mini compressor doesn't have a pressure valve. it is fixed at

And said it was so.

You can attach a pressure relief valve in-line between the compressor and the air hose, unless the air hose is integrally attached to the compressor, and I hope it isn't, because that sounds reeeeally cheap.

Mark Schynert

Uh, in fact no. I think I learned this trick some years ago here on rec.models.scale, but don't remember from who I first heard about that... maybe Paul Boyer or Al Superczynski.

Anyway, if you can spray only at 30 psi I suspect this is the main problem. As Mike wrote, look if you can put a pressure valve between the compressor and the airbrush to lower the pressure to 10-15 psi.

My 0.02