Figure 1
Low Profile Grease Cup Screw: Jeff has replaced the top grease cup screw with a much shorter/thinner one (Figure 2-2). This doesn't improve the performance of the airbrush, but makes it a lot more comfortable to hold (Figure 6). After several hours of non-stop work it can really make a difference.
Figure 3
The Trigger Assembly: Jeff uses two trigger assemblies on his AB. The original assembly has a short trigger (Figure 2-5a) and the modified assembly has an extended trigger (Figure 3-5b).
The extended trigger allows for more control when moving the needle in
front of the blast jet. With a longer lever the thumb/finger must
travel a greater distance to move the needle. It is very easy to switch
between long and short triggers by tightening each assembly by hand.
This allows for easy loosening and doesn't strip the delicate brass
threads by overtightening.
Figure 5
Handle Plug: Jeff has opted to removed the red handle that was supplied with his stock AB (Figure 7) because of the way he holds the airbrush (Figure 6). A replacement rubber eyedropper tip gives Jeff more comfort and versatility when holding the airbrush (Figures 2-4 & 3-4).
When the eyedropper tip is trimmed, it fits snugly inside the hollow
end of the airbrush body. Over time the metal threads inside the ABs
body will form a molded impression on the rubber tip. Over time this
impression will help hold the tip in place, although it should fit well
from the start. Spectralite, Marshals, and Shmenke inks and dyes come
in bottles with rubber tips that also work.
Figure 6
Further Reading: The
original parts list and instructions for the factory AB can be viewed
by clicking the following link. This is essential reading for
understanding how the AB works. Adobe Acrobat Reader must be installed
on your computer to view the file. Click on the "Get Acrobat Reader"
button below to install it.
Paasche's AB Instructions
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Sharpening a needle: The
taper on an original needle can be lengthened by sharpening its tip.
This allows for greater control of the spray diameter over a greater
distance of needle travel. Figure 1 shows
the difference in a hairline spray diameter between a standard needle
and one that is sharpened. The red arrows indicate the area of
increased performance. The dotted black arrows indicate the effective
spray area along the needle. Figure 4-1
shows a good view of a sharpened needle extended in front of the blast
jet. I use a sharpening stone with a jewelers motor to sharpen my
needles. However, 1500-2000 grit sand paper also works well for
sharpening a needle. I use this kind of sand paper frequently to polish
and remove dried paint from my needles. Two drawbacks of hand held sand
paper are sharpening time and needle roundness. Needles must be turned
and carefully checked for roundness while being sharpened. A needle
shaft that is elliptical in shape will sometimes produce an uneven
spray pattern. A good round needle will produce an almost perfectly
round spray pattern if the airbrush is held steady. This sharpening
technique is also documented in "The Complete Manual of Airbrushing" by
Peter Owen & Jane Rollason (out of print).
Figure 2
Custom Blast Jet: Jeffs custom made blast jet produces a stream of air about half the diameter of the factory supplied blast jet (Figures 4-3, &5).
It was made from a .125" solid brass rod using a jewellers motor,
sharpening stone, .3 millimeter & .8 millimeter micro drill bits,
and jewellers dies. A tighter spray diameter and sharper needle produce
a very thin line (Figure 1). The airbrush
needle needs to be perfectly aligned in front of the blast hole for
this to work. Also, the airbrush needs to be run slightly higher than
the recommended 25-35 PSI, but no more than 50 PSI. Spray may become
uneven when the needle is fully extended in front of the blast hole.
This is due to the fact that the diameter of the blast hole is not much
larger than the thickest part of the needle. The combination of a
smaller blast hole and sharpened needle is well worth this small
compromise for increased precision on the detail end. Jeff uses two
other unmodified Iwata airbrush models (CM-B and HP-BC) for wider and
faster paint coverage.
Figure 4
Some Words of Caution!
Some
of the unusual alterations described on this page should not be
attempted unless you are extremely familiar with this airbrush. You can
easily destroy the airbrush or any of its components. The damage may
not be apparent until the airbrush is actually used. Stripping threads,
bending needles, and creating air leaks are common examples of this.
Please carefully read the original instructions that came with your AB
before making any modifications. There is a link to the AB instructions
under Further Reading on this page.
DISCLAIMER: Jeff takes no responsibility for any damage that results to any airbrush except his own.
Figure 7
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