Airbrushing and PSI

Discussion in 'FAQs' started by aartwmich, Dec 28, 2002.

  1. aartwmich

    aartwmich Member

    I just read TomPM's excellent 'how to' post on airbrushing with craft paints and it sparked a question in my mind. I've searched this forum and read all I could find on airbrushing and one thing that struck me was the range of pressures people use. 22-43 PSI.

    Why the differences?

    Does it depend on the type of brush? ie: single/double action-internal/external mix.

    Does it depend on the type of paint being used? lots of different kinds out there it seems

    Does it depend on the affect sought after? ie: a light dusting for misting backgrounds or weathering stock vs. a complete covering for painting stock or structures

    Or is it just personal preference?

    I just got an airbrush and have played with it just a bit and would think that a higher PSI would cause more overspray thus maybe wasting paint.

    Anyway..this neophyte is once again asking the sage experience represented on this forum to share thier opinions and expertise..
    Thanks :D
  2. TomPM

    TomPM Another Fried Egg Fan

    The one thing I found out was you have to experiment. When I was using Polly Scale paints I was in the 25 to 35 psi range. The Polly Scale paints are thinner coming out of the bottle than the Folk Art paints. I started using the Folk Art paints at 35 psi but I was having some clogging and coverage problems, so I just kept increasing the pressure until it seemed to work. It may depend on the particular airbrush you have also. Mine is a cheap model that came with my compressor.

    Right now I am not doing anything fancy. I am just painting freight cars. I still do all my weathering by brush.

    Since you are just starting out I highly recommend practicing. I had a bunch of old junk cars that I used as my practice models. I also used them to practice decaling on. Some of them look like a one eyed, one armed, drunk who is in dire need of drink did. I keep one on my workbench to remind me of how far I’ve come.
  3. Vic

    Vic Active Member

    Hi Tomboygirl, The correct answer to your question is "all of the above":) :D You get a 100 on your airbrush test!!!:D :D :D

    Like Tom said you do have to experiment a bit depending on what you are using. Its been my experience though that the higher the quality of the airbrush, and I'm afraid that translates into "the more expensive" the airbrush is, the less psi is required to use it. But on the other hand a good quality brush such as a Paache H model can be had for less than $100 and if taken care of it will last a lifetime. (I've seen that one as low as $59.95 at times).

    A good smooth operating compressor made for airbrush use is a must have too if you don't have a larger compressor with a tank and regulator. A moisture trap/regulator completes the set up. A braided hose is a good investment too if your brush did not come with one as they don't kink up.

    Remember that when airbrushing models many thin coats are better than one or two thick coats so you don't cover up details. Start with a 50-50 ratio of paint to thinner and adjust it from there
    both the paint and thinner ratio and the psi pressure.

    I airbrush everything from water colors to epoxies at 22 psi but over the years I've figured out just how to thin the various mediums.

    Don't forget to disassemble and clean your airbursh thourghly after you use it. Regardless of what kind of paint I use I like to use lacqure thinner to clean it as it will dissolve most anything.

    Don't know if this is "sage advice" but hope it helps.:) :D :D
  4. Railery

    Railery Member

    Airbrushing is the fastest why of painting. i use my airbrush for the models and for the layout. i found painting the scenery on the layout gave me alot of practice and i got alot painted in a short time frame. (not base coat, did that with 6" brush and can of interior latex paint).

    i have three hoses, the longest 25', has a built in regualtor, 15' hose, and a 6' hose (braided). i also have a regulator & a trap that i can insert any where in the lines, usually kept at the end of the 6'.

    For a couple of years i worked without a trap. i made sure i bled my tank after every use & leaving it open until i used it again. Before i started painting i blew the air out of the lines to clear any moisture. A moisture trap is much nicer to have.

    My psi levels varied from 22 to 35 depending on what i was working on. Different paints water/oil changed the psi too.
    i eventually just use a water base mixed with a couple drops of isopropyl alcholol. My paints are tube acrylic and i mix them with water and/or geso. i paint with india ink too that is also mixed with the isopropyl. i also mix with dry paint pigment. The paint tubes last forever, never go hard. i got a few 2 oz. bottles from a hospital that fit the end of my sprayer. Which makes it easier to paint with.

    India ink spayed nice at 22 psi and the acrylic at 30.

    Use a good smooth sweeping action and find your depth of spray ( that varies too on what u are painting).

    All in all, i would say is practice with what u have. Also when i bought my Paache and Compressor they did come with some instructions that help. :D i hope i didn't forget anything, anyway Vic and Tom covered it all too ;) :)
  5. aartwmich

    aartwmich Member

    Thanks to everyone who responded...I guess it's like most other things, experimentation and mistakes! :) Learning from others experiences is invaluable tho. From my experience so far I think a big key is balancing thinning of paint with PSI, I don't like using the higher pressures. But time will tell ;)

    Practice?!?!?! I HATE to practice!!..LOL.... but I will. I've done some of the placing dots on a grid and then painting lines between the dots but god thats boring:rolleyes: But it did give me the hang of the double action brush, tricky but nice. In case you hadn't noticed, I can be rather impatient. Maybe taking up modeling again will help me improve upon that :)

    I have a pretty nice setup I think, got it at an art store so I probably paid too much tho they did cut me a discount for buying the whole rig. I've got a Badger double-action internal mix brush model 155-7 which came with a 6' braided hose, that standard cup and some bottles with siphon caps. My compressor is a Badger Cyclone I model 180-1, diaphram type, 40PSI max., never needs oiling. A Wilkerson 50-054 regulator with filter trap and gauge.

    I made up an easel out of pegboard with adjustable legs that I saw on another forum, this makes painting MUCH easier. I got some waterbased paints that I've been playing with, now I need to get more paint and more bottles.

    Heres my first experiment at scenery, and all the things wrong with Didn't prime wood..I'm impatient and I just wanted to Used paper for templates..too flimsy. Didn't use template for hills..too fuzzy. But I learned alot and the clouds actually look pretty good, better in this pic than in person. :)

    Attached Files:

  6. Vic

    Vic Active Member

    Hi Tomboygirl, Looks like you've got it going on with the airbrush:) Keep it going:) :D

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