Issues with shooting scalecoat paint

[CodyO]

Recently airbrushing has been a PITA. I used to at least be able to reliably paint models but my last time I ended up with a Smooth side passenger car having a roof like textured side.

I`ve been using a paasche single action airbrush and compressor.

Seems to shoot good, least it looked good while painting and then I ended up with the textured surface.

Is it my paint mixture? Air Pressure? Should i revert back to my double action badger brush?

Being unable to reliably paint models has been really killing my modeling mojo lately so appreciate any tips

[peteski]

Since you were successful in the past (assuming wiht the same equipment and some paint), something had to change.  Any idea what changed?

Um, you did mention reverting to the dual-action airbrush. SO is that the change?  Then yes, go back to the airbrush which worked.

I'm also  puzzled that you say that the painted surface looks fine while painting but rough (pebbly) when dry?  That is odd - usually pebbly surface is there right when you are spraying the paint.  It usually means that the paint is partially drying before hitting the model's surface, so it will not level out on the surface.  Maybe the paint went bad and became gritty, so when the paint is wet it looks smooth, but when the solvent evaporates the small chinks in the paint are exposed?  Or maybe you didn't mix the pain thoroughly enough?
Or maybe the models surface is rough?

I would either try using the same paint and going to the old airbrush, or try another bottle (color) of paint in the new airbrush.   You can test your painting technique on cheap disposable polystyrene plastic spoons.  Don't buy the more flexible polyethylene spoons.

[Rasputen]

On my Paasche single action unit, every once in a while I will get some paint built up around the air outlet hole.  This will affect the direction of airflow around the paint nozzle and make the spray pattern inconsistent.  I recommend cleaning the area around the air outlet with some nice strong lacquer thinner.

[thomasjmdavis]

It sounds like something is effecting the paint- given that it looks good while spraying.  A couple things that come to mind as possibilities are water in the airline (do you have a filter?), air temp of the intake air going into the compressor (air brushes and paint don't react well to cold or hot air), and the possibility of some substance on the surface being painted.  Plus all the things in the previous comments.

You mention the new airbrush is single action and the old one double action.  What about internal v external mix?

[chicken45]

Did you consider maybe you just suck?



LOL you know I'm trolling' bruh.


I sort of wish I had a single action airbrush for doing these kinds of things. You can dial it in and then "set it and forget it" as you spray multiple cars.

[peteski]

I sort of wish I had a single action airbrush for doing these kinds of things. You can dial it in and then "set it and forget it" as you spray multiple cars.

Feeling rambunctious today? 
Who says you are stuck owning just one airbrush. You know, single-action airbrushes aren't very expensive (you and find them for a price of some of N scale freight cars). Just ask Daniel  Leavitt - he owns more than half a dozen.

[PaulCoats]

As your paint ages sitting around doing nothing it dries and thickens.  You can't use just one formulat, x drops of this and y drops of that.  You
have to get the right consistency.

Also, weather can affect it.

You may need to add some lacquer retarder to your thinner mix.

[robert3985]

What almost always causes "pebbly" paint is too much air...the paint is dry before it hits the surface.  Ideally, your paint should go on wet, but just wet enough to form a smooth surface and stick to the surface...not drippy or runny.

Airbrushes vary according to type, so your new single action airbrush needs to be "dialed in" before starting on a serious project.  I have several old N-scale cars that I test paint first when I'm changing airbrushes to make sure I've got my brush's air vs paint mixture correct and to get the right distance from the model too.  EDIT:  The polystyrene plastic spoons idea is a great idea.  I'll be doing that on my next paint job!  Adding thinner will also allow your paint to hit the surface wetter, so perhaps you need your paint to be a bit less thick.  First thing I'd try is to lessen your air pressure.  If that doesn't cure the problem, then I'd thin the paint more.  Then, I'd make sure I'm not too far from the model.

Another aspect is to make sure your air is clean and dry.  I run a filter at my compressors regulator before the air goes into my big airhose, which de-oils and filters the water out.  I have a smaller regulator/filter which gets attached to the big hose which allows me fine control of my air pressure, and it catches any oil/water that the first filter back at the compressor misses.  Additionally, I run a Paasche moisture trap (here: https://www.dickblick.com/products/moisture-trap/  ) on every small airbrush hose which attaches directly to my airbrushes.  Maybe this is overkill, but from years of fine-art airbrushing professionally, I don't want any oil or water spitting out and ruining a paint job after all the time and effort expended to prep and mask.

Lastly, I've found that stirring the paint is much better than shaking the bottle.  I "stir" the paint with a miniature Badger paint mixer that's battery powered.  This works really well, and gets all of the settled-out pigment off the bottom of the bottles and into solution without clumps except for acrylic paints, which form a big blob around the metal shaft, making it easy to remove that dried paint from the bottle before spraying with it.  I got mine from Micro Mark years ago and I assume they still carry them, but they're available at other places too, like here: https://www.modeltrainstuff.com/badger-121-paint-mixer/?ne_ppc_id=1079742151&gclid=Cj0KCQjw6cHoBRDdARIsADiTTzZVWMalJvpzrJGfeXal6jV8NTZvM1_9IRNK6CzeNwFN_yBZp1H17KoaAg83EALw_wcB

If, after all of these efforts, you still get a bad paint surface, then I'd suggest you return to your double action airbrush.  I've got 7 Paasche airbrushes and 2 Aztek brushes, and not a single action brush among them.

GOOD LUCK!

Cheerio!
Bob Gilmore

[wazzou]

Further to what Bob mentions above, buy a box of white plastic spoons and use those for practice and fine tuning your mixture.

[Lemosteam]

Further to what Bob mentions above, buy a box of white plastic spoons and use those for practice and fine tuning your mixture.

OK pestesk... Er wazzou

[wazzou]

OK pestesk... Er wazzou

Good old Model Cars Magazine Forum trick.

[peteski]

Good old Model Cars Magazine Forum trick.

Yes, plastic spoons are perfect for paint compatibility tests.  Best are the cheap polystyrene spoons, since it is the same material that model shells (or car bodies) are made of.  If some "hot" paint attacks (crazes), it will likely do the same to the model's surface.  But some plastic spoons are made from different (more flexible) plastic. The cheapest ones are usually polystyrene, but to confirm look for the #6 recycling symbol.

Another car modeler trick, for testing paint's appearance and spraying technique on larger scale it to paint empty plastic soft-drink bottles.  Using them will give you opportunity to practice getting good smooth coverage on larger surfaces.

[Lemosteam]

Yes, plastic spoons are perfect for paint compatibility tests.  Best are the cheap polystyrene spoons, since it is the same material that model shells (or car bodies) are made of.  If some "hot" paint attacks (crazes), it will likely do the same to the model's surface.  But some plastic spoons are made from different (more flexible) plastic. The cheapest ones are usually polystyrene, but to confirm look for the #6 recycling symbol.

Another car modeler trick, for testing paint's appearance and spraying technique on larger scale it to paint empty plastic soft-drink bottles.  Using them will give you opportunity to practice getting good smooth coverage on larger surfaces.

Would you say that at least a passel of each is required?

[peteski]

Would you say that at least a passel of each is required?

Sure, it never hurts to have lots of plastic spoons and empty soft-drink bottles on hand for paint trials.