Parts of an airbrush and how to disassemble it This section is on the components of an air brush and how to care for it to provide the best results when you need it. To begin with
I’ll go through my Badger 200 air brush. It’s a single action, internal mix air brush. A rugged all metal design that’ll spray just about any
kind of fluid thin enough to go through the nozzle. The components of this brush are the same regardless of bottle or cup.
From the photograph, below, of my Badger 200 you’ll see it broken down into its principle components. Starting at the top of the
picture we have the
needle. On the right hand side of the needle is the collect that entraps the needle so it can be run in and
out of the brush by the
needle adjusting screw.
Below the needle is the
trigger. This is what you push down with your index finger to make the brush work. By pressing it down
you are opening the valve at the air inlet to the brush. (I haven’t disassembled this part since it has a spring, sealing washer and
plunger in it). The opening in the trigger allows the needle to pass through to reach the head.
Below the trigger is the
air brush body that the above components fit into. The blue end of the body is detachable from the
chrome portion; however it is only a hollow tube. Air brushes have these long back end extensions to aid in balancing out the air brush
to make it easier to operate consistently. Between the air entry and the paint pickup points on the body, inside the body is a very small
Teflon (PTFE) washer/guide. Its purpose is to seal the air portion from the paint portion inside the brush and allow the needle
to pass through.
To the left of the body is the
head and tip of the brush. These are successively screwed into the brush body, with the head having a
Teflon (PTFE) sealing washer (the white ring) again to separate air and paint at this point.
This is the important part of the air brush. The part that makes the difference in how the brush will perform and the degree of paint you get on your work. The needle passes
through the center of the head. The inside of it is
tapered to match the appropriate needle. In other words, a fine needle should
have a matching fine head for the brush to work properly. I have mixed and matched and had variable to poor results with the mixed
head /needle combination. Stick to the matched pairs.
The mixing of the paint and air happens at the very tip of the head where the needle just protrudes through the head. The action of the air passing over this opening creates a vacuum on the paint side
drawing paint up to the opening. Then the paint and air combine and go out through the tip to the work being painted.
This, then, comprises the main components of a single action, internal mix air brush. The
double action brush is very similar except for
one key area.
The trigger, as well as pushing down the air valve to open it, also moves the paint needle back and forth to give the
desired amount of paint during spraying. In this case the paint needle has a spring to naturally return the needle to close when the
finger is released plus the mechanical bits to make the trigger work the needle. The needle also has the same collect and adjustment
screw on the end it. This allows the major pre spraying adjustment to be made to “zero” the brush before use.
As I’ve mentioned before, these the brush manufacturers make, or should make, extra needles, heads, and tips, to make the air brush
able to spray fine, medium or heavy paint outputs. This is a tremendous advantage for modelers. One brush can cover all the jobs we
want to do on a model. The heavy components will move enough paint to do an admirable job on painting the hull, while the fine is
great for doing weathering a little at a time and in close quarters.
Fine tip – for low viscosity paints. It will not pass heavy viscosity course pigment paints.
Medium tip – for detail work and can spray a line from 1/16” to 1 ½” across.
It will handle most lacquers, acrylics and hobby enamels. It will spray 2 times the amount of paint as a fine tip.
Heavy tip – will spray from 1/8” to 2” line and spray 4 times the paint of a fine tip.
It can be used with automotive lacquers, ceramic glazes and acrylics.
Components of the Badger 200 air brush
The needle in the brush body and the head to the left with its white Teflon washer
CARE OF THE BRUSH When using an air brush be very aware it is not to be used heavy handed. Although the components are rugged on this type of brush,
they won’t stand abuse, the result of which is either money out of pocket or a ruined paint job.
One area to be aware of is the needle and head arrangement. The needle projects into the head. The orifice around the outside of
the needle is what determines the amount of paint issuing from the brush. If you drive the needle too far into the brush the taper in
the head can split. (See photo of needle inside the head). This results in a ragged spray pattern that will lead to paint coming out in
drops and gobs and landing intermittently on your nice new paint job. The solution, don’t force the needle into the head. Stop when
you feel resistance.
If you don’t clean the brush and try and remove the needle with dried paint on it you can ruin the small Teflon guide bearing seal inside
the body of the brush. Done that, got the “T” shirt. The dried paint will build up on the needle shaft. When you pull it back through
the Teflon guide, it tears the Teflon and allows air to get into the paint portion of the air brush body. You will soon know when you
try and spray paint. The paint will sputter out the tip and intermittently come out in gobs. No amount of adjusting will make a difference.
The solution is a new Teflon guide/seal. I found I had to make a special tool to install a new one. Not bad once you’ve made the tool,
but still an aggravation. Since you may get this sputter after a lot of use of your brush, again due to wear on the Teflon guide, you
can put bee’s wax on the paint needle before you reinstall it into the guide. This will, hopefully, seal any scratches in the guide and cure
the problem. I’ve used a very small amount of Vaseline with great success.
The reason of
“pffft – pffft” of the paint is because air has got into the paint side. Since this type of brushes relies on vacuum
to raise the paint from the cup or jar, allowing air into the paint area breaks the vacuum cutting off the paint supply. Paint drifts back
from the tip, seals the guide and paint lifts again under vacuum until air comes back through the guide again. This all happens very
rapidly, but makes it impossible to get a good paint job.
In order to clean a brush I have found it’s not necessary to disassemble the brush. Others may disagree which is fine. If you feel you
want to disassemble the brush that’s fine. I just haven’t found a need for based on my experience. Before you start painting be sure
to have a bottle of the cleaning solvent, you use for the paint used, at hand. When you are finished spraying, put a paper cloth over
the discharge end of the air brush and press the trigger. This will blow back the brush to clear out any paint inside the brush body
and pick up tube.
Remove the paint bottle from the brush and tie on your bottle of solvent. Press the trigger and spray the brush as you would when
painting something. Work the needle in and out of the brush head with the adjusting screw to ensure any lumps get a chance of
blowing through. When you feel you’ve sprayed enough through the brush, spray the brush against piece of white paper or cardboard.
If it comes out clear, you’re finished cleaning. If your still get colour, keep spraying solvent to clean the brush. It takes less time to do it
than it does for me to write about it. When you’re satisfied you’re clean, blow back the brush again to blow out any solvent. Put the
protective cap on the brush and hang it up, you’re done.
Very occasionally the tip may need to be removed to clean out any paint build up over time. Simply let it sit in a lacquer solvent and
wash out the paint. You’re good to go again. Clean the bottles and cups as you would with any other clean up and you’re ready to go again.
That about does it for this section, but I’m sure there are many questions. Step up and we’ll see what we can do.
John

Needle in the air brush head. Be careful not to split this delicate part when running the needle into close the opening.