Newsgroups: rec.models.railroad
Subject: Painting Brass (revisited)
From: macman+@pitt.edu (Dennis H Lippert)
Date: 9 Jan 93 23:27:47 GMT
Distribution: usa
Organization: University of Pittsburgh
Originator: macman@unixd3.cis.pitt.edu

This is an article I posted several months back... I hope it's of some 
help with the "painting brass" thread:

--- Begin forwarded article ---

Well, being handy with an airbrush is the "only" place to start playing with
brass... if you don't already have some experience... practice 
airbrushing on some less-expensive (and less detailed) stuff.

My "system" for painting brass steam locos has always been basically the 
following:

(1) Test-run the loco... to make sure it ran before you took it apart(!). 
Check all of the valve gear and rods for loose screws, tighening if 
found. It might even be a good idea to fully break-in the loco before 
putting it through the "trauma" of disassembly.

(2) Disassmble as follows: remove lead & trailing trucks.  Detach the 
boiler from the frame. Install the weight (if it was just wrapped up 
and sittiing in the box). Remove the trucks and couplers from the tender, 
and remove its body from the frame also.  If the smokebox front is 
removeable, you might want to take it off also. This *should* be all the 
disassembly that will be necessary.

(3) Inspect the model.  Fix anything broken, and check out the factory
clear-coat lacquer.  If the lacquer seems to be smooth and isn't chipping
off, use it as a primer for your paint.  If the lacquer is no good, strip
the loco (I use ScaleCoat's stripper).

(4) Wash the loco with soap and "water as hot as you can stand".  This is
to make the surface clean so the paint will stick better. Don't worry 
about getting the motor/drive wet.  As long as it dries completely
before putting power to it, it will be OK.  Let the model dry for at least
a few hours, preferably overnight. After washing the parts, always wash 
your hands before touching the model (or better yet, wear rubber gloves).

(5) If the loco was stripped, it needs to be primed. I use a PPG two-part
epoxy primer (because a friend got it for me), code-named DP400/DP401. You
mix equal parts of the two bottles, let sit for 30 minutes, then thin 
with lacquer thinner and spray (it will only last a couple weeks in the 
bottle after being mixed, so don't mix much).  It should be noted that 
Floquil's "primers" are basically just paint colors with thicker pigment 
(for sanding). They DO NOT adhere to the surface any better than the normal 
paints (this from a PPG paint chemist who has "chemically dissected" them).

(6) Prepare your paint.  I like Scalecoat II because of it's good coverage 
and shiny surface.  You get the best smoothness if the paint is slightly 
on the thin side, rather than slightly thick.  But just *slightly*. (if 
Scalecoat is overthinned, it will chemically "fall apart".

(7) Adjust the airbrush to spray a very small amount of paint.  Our first 
area of attack will be the chassis.  Connect power leads to the frame and
the drawbar, and put about half-power to the chassis.  Hold it by the motor
(assuming can motor), and spray all of the stuff that's moving, from 
various angles.  sit the chassis aside, upside down, and leave it running
for five to ten minutes (to make sure the paint doesn't stick anything 
together when it dries.) Since the airbrush is turned down right now, 
we can also spray the lead truck, trailing truck, tender trucks, etc.  
Be sure to hit them from many angles, and to roll them around while painting 
them. ( A skill in itself... hitting a moving target! :-) Possibly the 
single biggest trick in airbrushing brass is getting paint on everything 
that will be seen (a bare spot under a detail on a black plastic loco 
looks like a shadow... on brass it looks like someone forgot to paint 
it!)

(8) open the airbrush up to a "normal" spray pattern.  Start to spray any 
part (boiler, tender, etc.) Begin by spraying from obscure angles around all
details.  Then come back and lay a smooth overcoat over the entire area.

(9) once done with the main body parts, you can come back to the chassis.
Spray all non-moving parts with the "heavier" spray pattern.  Try to avoid
spraying on the moving parts (since they're already painted).  Again, the
motor is the nicest handle to hold with.

(10) Now you should notice that everything is painted (unless I missed
something).  In the case of a PRR steamer, the boiler and tender body should
be brunswick green, the chassis components should all be black. Take 
some time to look at all the parts from any angle that you can... there 
WILL be bare spots somewhere (trust me!)

(11) Wait for things to dry.  With Scalecoat I paint, this can take days to 
quit being tacky.  Suggestions to speed drying include:
  -put it outside if it's a nice warm sunny day... in the sun.
  -put it in front of a forced-air furnace (warm, dry air is good)
  -bake it (I've never "baked" - don't look to me for suggestions

The best idea is to do one of the above to remove the tackyness, and still
let the parts sit for a week. This guarantees that everything is dry and
hard.

(12) prepare for next color(s).  On most steamers this would include graphite
smokeboxes, Oxide red tender decks/cab roofs, etc.  Check your prototype!
Mask carefully, but prepare yourself for the fact that you *will* get 
overspray under the masking.  Luckily, black is easy to touch up.  Always
"overdo it" with metallic colors, and cover up the overspray later. 
The metallics are incredibly hard to touch up without it showing, so make 
sure everything that is to be metallic gets sprayed the first time.

(13) Apply next color(s).  Using a very low pressure (10-15 psi) to keep
overspray to a minimum. Remove masking as soon as you are done. "Bake" again.
[You can often do two or more "extra" colors at one sitting... as long as
they aren't too close to each other on the model (overspray problems).]

(14) Clean paint from parts which must make electrical contact.  These 
include tender truck bolsters, wheel treads, drawbar, etc. with lacquer 
thinner and Q-Tips. The engine drive wheels are easiest to clean if you 
again run the chassis on a power pack.

(13) Reassemble the loco.  After reassembly, do any kind of touch-up work
and details.  (i.e. if you did a graphite smokebox, the railings, etc. will
also be graphite, so repaint them [black]).

(14) Dullcote the loco (or semi-gloss) after decaling. This will seal the
decals and give "an extra layer of protection" against chips.

(15) Weather the loco if you like, wrap it up, take it to the club, and
begin to brag.  This is the most important step, as very few people seem
to realize that it takes more real effort to read this message than it
does to get a good paint job on a brass model!

Above all, follow these simple rules:
- have fun... painting your first couple of brass locos can be stressful.
- take your time... it's not that important to get done today (or even 
  this week!).
- use a spray booth, rubber gloves, and possibly a respirator.  A simple
  mask won't help much... as the pigment is the least of your worries. 
  These may seem like overkill, but we are looking at a couple of hours 
  at the booth... much more time than, say, painting a freight car.

---------------------------------------------------------------------------
The above comes from a new-age veteran of brass painting... I only started
with an airbrush 6 years ago, and have since painted on the order of 25
brass steamers... for friends mainly... so you know it works! (Yes, I *do*
have repeat customers).

Hope it helps!
-Den
-- 
==========================================================================
  Dennis Lippert   -   macman+@pitt.edu    or    macman@vm2.cis.pitt.edu
The "Mac Maniac" operator at the Sutherland Hall Lab - Univ. of Pittsburgh
                             "Just the Macs, Man"