HOW TO PAINT YOUR OWN MODELS
PART 2-PREPARATION of the MODEL

These are the methods I utilize and are not necessarily the only methods or the manufacturers recommendations, all I can say is "They work for me"

Preparation begins during construction of the model. Certain items that would interfere with the application of decals are better left off until after painting and decaling. Examples are grab irons, all details on pilots where stripes are applied with decals and glazing for windows. The model is easier painted if not fully assembled.

Where the hood and walkways are separate parts they should not be joined until after the painting is done. Sideframes on the trucks should be removed for painting.

Brush painting of the truck mechanism and wheel sides, can be accomplished at this time. If you are stripping the paint from a factory painted model, now is the time to accomplish this task. I recommend using eye and hand protection for any paint removal.

A good set of safety glasses and a pair of latex gloves will save you from potential problems. Paint removers in the eye or on the skin are not good ideas.

SOME CHEMICAL METHODS FOR STRIPPING PAINT

  • BRASS, CAST ALLOY BODIES AND FRAMES. Use Lacquer thinner and a fairly stiff brush. A brass bristle brush works well on cast alloy bodies and frames. Use gloves and eye protection!

  • POLYSTYRENE, ABS AND OTHER PLASTICS. There are several commercial strippers that work. If you have used them with success, then by all means keep using them.
    I prefer 91% isopropyl alcohol which is now available at most Pharmacies. Even with several days soaking the 91% isopropyl alcohol does no harm to the plastic. Most paints comes off with only an hour or so of soaking. You need to have a closed container as it evaporates fairly rapidly. It helps to use an old toothbrush to get all the paint out of the crevices. Some paint in door latches etc can be prodded out with a toothpick. Rinse well and wash with a detergent. Use eye protection
    NOTE: 70% isopropyl alcohol(rubbing alcohol)will not remove the paint, but does an excellent job of cleaning up an old model.

SOME MECHANICAL METHODS FOR STRIPPING PAINT

  • Mechanical removal of paint is accomplished by blowing an abrasive onto the surface of the model.
    This requires an air compressor, "blaster gun", and an enclosure to contain the blown abrasive.
    The size of the air compressor is determined by the size of the blaster gun's nozzle and the pressure being used. A gun with a 5mm nozzle blowing abrasive at 90 psi consumes approx. 14 cfm wide open. The same gun at 40 psi consumes about 5cfm. A compressor that can deliver 14 cfm at 90 psi requires about 8hp. There is no need to operate the blaster gun wide open for extended periods, most model paint removal is done in short blasts. A Compressor with a storage tank can accomodate these short bursts. Most should get by with a much smaller compressor by using 40 psi or so. A 5 hp compressor with a 10-12 gallon tank should work just fine.

    The next item needed is the blaster gun and enclosure. Many suppliers offer these units which come with the blaster gun, enclosure view window, air connections, interior light, and external connection for a vacuum cleaner. The vacuum cleaner is to remove the dust inside the unit which sometimes obscures your vision.

    Another item is an "Air Eraser" looks like and consumes no more air than a standard airbrush, say about 2-3 cfm at 40 psi.

  • BRASS, CAST ALLOY BODIES AND FRAMES. Use the full size (5mm nozzle) gun and from 40-90 psi and an abrasive of around 200 grit or lower number. Use gloves furnished inside the booth, don't direct the nozzle toward your hand, and always use eye protection! If for any reason the view window should shatter or fly open your last line of defense is the eye protection. Never blast outside the booth with the large blast gun. It will not only make a heck of a mess but the abrasive is very harmful as you breathe it in.

  • POLYSTYRENE, ABS AND OTHER PLASTICS. Use from 20-80 psi and abrasive grits of 300 or higher. Use no more pressure than required to remove the paint. To remove lettering only use an "Air Eraser". The abrasive can be ordinary baking soda or cornstarch. Use around 30-40 psi and work slowly, the factory lettering will come off before the underlying paint. A good idea to mask off the area where the lettering is to prevent damage to surrounding areas.

    Using an "Air Eraser" and baking soda can be done outside the house, garage etc. This method will waste the baking soda which is cheap and easily replaceable. Use a heavy glove like the ones in the booth or a holder like used to hold a body when spray painting. Don't hold with your bare hand! Use eye protection and a paper paint mask. 


I cannot recommend anything else, although i have tried them all and some work but
are dangerous, costly or require extreme care so as notto damage the plastic.  if
you have other methods, continue to use them....


preparing a model for painting: any type paint...

1. wash model thoroughly with dishwashing detergent, use a soft brush to
spread the washing liquid over all surfaces.  this is  good time to wash
thoroughly your hands to remove the greases present on them.
note: dishwashing detergent has degreasers built in, many hand soaps have
lanolin or greases in them and this will be deposited on the surface of the
model.
2. rinse both the model and your hands thoroughly to remove all detergent...

3. shake the excess water off the model, dry your hands on a clean hand towel.
blow dry with an airbrush or hair dryer, don't use paper towells as they
leave fuzzies on the model.

4. when the model is thoroughly dry, handle with the bare hands as little
as possible.

5. the primer coat can now be applied.  let dry an appropriate time or use
hair dryer again to hasten drying...

6. apply primary color after the primer is dry.  again let dry an
appropriate time or use hair dryer again to hasten drying...improperly
cured paint is subject to lifting later.

7. mask with model masking tape  a good choice is scotch 2090 long mask.
this is designed for use on latex wall paint and automobile finishes.  i
always press mine on a plate of steel or mirror and lift several times
before applying to the model...

8. burnish tape edges only where edge meets the primary color.  always use
a fresh cut edge for masking, the factory edges are not as sharp and don't
seal as well as a fresh cut.

9. apply secondary color.  again let dry an appropriate time or use hair
dryer again to hasten drying...improperly cured paint is subject to lifting
later.

10. remove the masking tape by pulling back at as sharp an angle as
possible to minimize the possibility of the primary paint lifting.

11. the model should be ready for decals at this point...sam...

12.if you don't have an airbrush you can stop reading here.  these tips assume the use of an air brush.  

13.the wheels sides and truck mechanism can be cleaned with a "q" tip and some 70%
alcohol.  while you are washing the parts, make sure to wash your hands to remove
the oils present there.  
after the parts are washed and dried, handle as little as possible.

you are ready now to go to part 3.  painting the model.
© S.A. McCall