Model Forum / General / Models / October 2007

on 10/13/2007 11:57 AM Dingo said the following:

I've read that the pressure for spraying models is between 10 and 20 psi.

Painting on the sprue has its advantages. You can spray everything at
once with the base color, and/or just spray certain items with different
colors . The best thing is that you have a handle on the parts, so you
can turn the parts easier for spraying.
The disadvantages are the flash and sprue connectors that have to be cut
off and sanded. You can use a brush or a quick spray to cover them up.

First read this: http://www.ipms-seattle.org/tips/hints.htm (the
Holowchuk tips are a treasure-trove of information)

Second... 45PSI for our use is way too much. That's the sort of pressure
I use when I want to clean it by shooting lacquer thinner through it
(it's fast at that pressure). Someone said 10-20PSI..I rarely get as low
as 12 or 13, but do max out around 20. At 20, you've got an awful lot of
air and the paint may dry before hitting the model. When that happens,
you get a very rough surface. Start around 15PSI and see how it feels.

On sprue or off? I always always always do it off. I think the beauty of
airbrushing is the perfect surface that you get. If you clean up with a
paint brush later, chances are that you're going to mess it up.

For my last project, I had a bunch of bombs to paint. I painted them in
two airbrush sessions. First session, I shot everything execpt the rear
of the bombs. I had them stuck to masking tape on a piece of cardboard
so couldn't paint their rear ends. The next session with the same color,
I held the front of the bombs with masking tape and shot the rear ends.
It was no big deal.

The more you get used to your airbrush, the faster you'll be with color
changes and won't be intimidated about shooting your models. I
frequently will do several colors in an airbrushing session, going from
light to dark, and just shooting lots of lacquer thinner through the
brush in between colors.

Have fun!! You've just taken a HUGE step forward in modeling.

Oh, what's your air source?

--- Stephen

I almost always airbrush at 15 psi with the paint, as you say, thinned to
about the consistency of milk. It may be that you can use slightly thicker
paint at higher pressure, which may cover more easily. It's something you
could experiment with. You definitely have to be careful about using too
much pressure with over-thinned paint -- it becomes more difficult to avoid
puddling or bullseyes where too much paint is applied too wet to a small
area.

If the attachment point is going to be visible, I think it's more efficient
to detach the part before painting. You're probably going to have to do some
minor surfacing at the attachment point; if there's already paint in the
area, it just gets in the way. I use the cover to an old cookie tin. I make
a flattened loop of masking tape with the adhesive out. Thetape sticks to
the cover, and the parts to be painted stick to the tape.

HTH.
Pip Moss