and might not stick to the surface. If the paint beads up, it’s too
thin. Alcohol-based thinners like windshield washer fluid can
cause paints to dry too quickly and raise havoc with an airbrush.
All craft acrylics must be mixed thoroughly, and strained through
a #40 or #60 screen before they are used with an airbrush.
Ammonia can be used to thin acrylic paints, and works much bet-
ter than water alone. Many people are not too keen on the aroma.
Pure 90% isopropyl alcohol can cause some craft acrylics to gel and
clot, but ammonia does a great job of helping them flow out. Make
up a sample and test before spraying your masterpiece.
When you thin your paint you are making the bonds between the
acrylic polymers weaker. Weaker paint tends to chip and flake
more easily. I learned to use a product called acrylic airbrush
medium. This thins your acrylic paint and preserves the strength
because it’s essentially clear paint (binder with no pigment
added). It’s about the consistency of skimmilk and thins most
paints beautifully.
Liquitex, Golden, and other makers of artists acrylic paint mar-
ket acrylic airbrush medium [4]. It does not affect drying times
significantly. There are also acrylic extenders available in art
stores and paint stores than can extend the drying time.
Phil H.:
Windshield washer fluid thinner works well for me.
You have to do it to about the consistency of skim milk to be
effective in most double-action airbrushes. You also need to stir
it up really well. Shaking doesn’t suspend the pigment properly.
Rio Grande Dan:
I have used a number of different glass
cleaners for thinning water base latex and acrylic paint, from
Windex to Glass Plus. The cheap blue stuff you find at the gas
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station works the best. I start with a 5-to-1 mix (5 parts paint
to 1 part thinner) and start with a small amount of paint and
washer fluid to test the mix first through the spray gun. You
don’t want it too thin, because the paint will dry before it hits
the project and give you a chalky effect. If it’s way too thin it will
run like rain. Too thick will clog up the airbrush.
TIPS
Car height gauge
Most lightweight passenger cars have a height from the rail head
to the roof top of 13’ 6”. Some people will try to adjust coupler
height without regard of car height, which can make a string of
cars look uneven. In order to keep my fleet of cars looking about
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5. A simple gauge made of styrene or wood will help keep
car heights consistent without fussy repeated measuring.
The lower plate checks the height of the Kadee uncoupling
pin. Joseph Oates photo
