Step 1 - Preparation:

Recommended Materials:
Sprue Cutters
X-acto Knife
Metal File(s)
Sandpaper (400, 600, 800 & 1200 grit)
Putty
Soft Scrub Soap & Water
Plastikote T235 Grey Primer
Optional - Plastikote White Primer

Proper preparation of a model car body is essential for a good finish, but is often an overlooked step. It is especially critical if you are painting with an airbrush. A thick coat of paint from a can can hide some flaws, but the airbrush will highlight them.

Start by removing all mold parting lines, flash and other imperfections. These are byproducts of the injection molding process, but do not exist on real cars. Sprue cutters and a metal file can be useful for thick sprue attachments at edges. Use the sandpaper and sanding sticks to remove mold lines and for work on surfaces which need to remain smooth. Fill all seams, scratches, gouges and sink marks with putty, and sand the putty smooth after it is fully cured. File down any thickened plastic that may build up along the edges of hoods, trunks, etc.

For good paint adhesion, the body must be primed. Plastikote T235 automotive primer sprays on nicely straight from the can. Two coats are adequate. The primer won't harm the plastic even though it is lacquer based. However, if you spray lacquer paint on unprimed plastic, it will craze the plastic, ruining the model. Although the primer will dry to the touch in a matter or minutes, it is advisable to let it dry for at least two days, before painting the model. This allows all the gasses in the lacquer to fully dissipate, preventing problems with paint sprayed over it. If the primer dries with a slight texture, gently sand it smooth with 1200 grit sandpaper. Primer will often make previously overlooked flaws on the model visible. If you see sink marks, scratches, or the remains of mold lines through the primer, repair them, and then reprime the surface.

The grey primer is sufficient for most paints. However, for white, yellow and light metallic colors, it is recommended to spray two additional coats of white primer over the gray primer.

Step 2 - Painting:

Good Paint Choices for Model Cars:
Testors Model Master (Enamel)
Testors Acryl (Acrylic)
Plastikote Spray Cans (Lacquer)
Plastikote Touch-up Bottle (Enamel)
MCW (Lacquer)
Tamiya Spray (Lacquer)

There are two ways to apply paint to a model car: with a spray can or an airbrush. Both can yield excellent finished results if done properly.

Spray cans tend to build up paint thickness quickly so fewer coats are needed. For non-metallic colors, 3 colors of paint should be sufficient. The first coat should be misted on lightly, followed by heavier coats for the second two.

For metallic colors, two coats of paint can be sufficient, as long as the color achieves a uniform consistency in these coats. If not, three coats can be applied.

Metallic colors must be covered with a compatible clear coat. Three coats of clear are recommended for proper polishing. It is Okay to spray acrylic clear over lacquer or enamels, and it's okay to put an enamel clear over lacquer. But, NEVER spray a lacquer over an enamel or acrylic. This is a sure way to craze the paint. If you are in doubt about paint compatibility, test it on a sample piece before trying it on your model.

An airbrush will apply paint thinner and more smoothly than is possible wit ha can. Start by applying 3 - 5 "mist" coats of the color. Spray at 15 - 20 psi, and allow 10 minutes between coats for lacquers, and 20 minutes for enamels and acrylics. A mist coat should be thin, cover all areas uniformly, but not look "wet" when applied.

The dried look of these coats will actually be flat or semi-gloss. After the mist coats have built up a solid base of color, apply 4 or more "wet" coats of paint, allowing 15 minutes between coats for lacquers, and 30 minutes for enamels and acrylics. Metallic paints should have 4 or 5 wet coats, while non-metallics should have 5 to 8. A metallic color must be covered with a compatible clear coat, as described above under the spray can technique.

Spray 4 - 6 wet coats of the clear coat. Sufficient depth of clear coat must be built up to avoid polishing through to the metallic layer later.

After all layers of paint are applied, it is very critical to allow an adequate drying time before polishing. Failure to do so can result in polishing down to sticky layers of paint that are not fully dried. Recommended drying times are as follows:
Enamels: 3 weeks
Acrylics: 2 - 3 weeks
Lacquers: 7 - 10 days

Because of the long drying times, it is recommended that the painting of the body be the first thing you do on a new model project. Then, you can work on the rest of the model while the body dries.

Step 3 - Polishing

Recommended Materials:
Detail Master Polishing Kit, (which includes polishing cloths, rubber sanding block, polish & directions)
Novus 1 & 2
Flannel Cloth
Index Card
White Cotton Gloves

Your model will be subjected to a lot of handling during the polishing process, so it is highly recommended that you wear clean, white cotton gloves while handling the car.

The most important step in polishing is doing a thorough job with the first polishing cloth. Your selection of what cloth to use first should be based on the finished texture of your paint job. If it came out very smooth with no embedded dust, starting with the 3600 cloth should work well. A moderate orange peel with small specks of dust should be started with the 3200 cloth. For very roughly textured finished or drips and runs, start with the 2400 cloth.

Most of your polishing time will be spent with this first cloth. Wrap it around the sanding block, and move it gently back and forth across the surface of the model. Maintain a uniform back and forth direction. Do not continually change direction or polish in a circular fashion. Apply only very light pressure to the block, letting the grit on the cloth do the work.

Be very careful around sharp edges and contours to ensure that you don't rub through the paint or clear coat. Polish the model with this cloth until the entire surface has a uniform flat, dull surface. Although you may be gripped with fear that you have destroyed the gloss finish, it is essential to actually make the finish as flat as possible in this first step. This first cloth essentially removed all damage and imperfections in the paint, while the remaining cloths will gradually restore the finish to a glossy shine.

Once you finish with the first cloth, switch to the next cloth. It is very important never to skip cloths during this process. Polish the entire surface with this cloth using very light pressure, but moving back and forth perpendicular to the direction you used for the first cloth. Continue with this cloth until the surface is uniformly smooth. The second cloth shouldn't take nearly as long as the first, but take care to be thorough with it. Check your work under a bright halogen desk lamp. After you are done with each cloth, move to the next cloth, again reversing the direction each time.  Each cloth will make the finish glossier, and by the time you are done with the 6000 grit cloth, you should be able to see reflections in the paint when you hold it under the lamp. Continue working your way up to the 12000-grit cloth.

After finishing with the polishing cloths, the model will have a smooth, glossy shine, but that shine will be a bit hazy. This haze is polished out with a series of liquid polishes. Use only a flannel cloth for these liquid polishes. Anything else can cause scratches to your finish. Dampen a small area of the flannel cloth, and use it to apply small amounts of the polish that came with the polishing kit. Apply this like care wax, using circular motion and more pressure than you used with the polishing cloths.

When the polish dries on the surface, wipe it away with a clean, dry portion of the cloth. Next, do the same thing with the Novus 2. This should restore the finish to a glossy, haze-free shine. If there is still some haze or fine scratches, repeat the application of the polish and the Novus 2 until you are satisfied.

During the process of applying liquid polish, it is inevitable that a good amount of polish will work its way into panel lines and crevices. Do not use a sharp tool like an X-acto blade or toothpick to scrape this polish out. Instead, let the polish dry thoroughly. Then, cut an index card into tiny strips. Use the corners and edges of this card to scrape the polish away. This is the safest way to do it without chipping or scratching the paint.

Finally, clean the entire model with Novus 1. This provides a protective, static-free layer of shine to your finished paint job. Just be aware that you cannot paint over Novus 1 - (the paint tends to "bead up.") It is recommended that you do any trim painting or detailing before the Novus 1. You can, however, apply details after using Novus 1.

Some Final Thoughts:

Preparing, painting and polishing a model care finish is a time consuming task that will take a lot of patience. However, it is not difficult, and the results of your hard work will be very satisfying. Remember, that what I have presented here is the technique and materials that I have found worked well for me over the course of building a dozen models. There are other methods and materials that may work just as well, if not better for you. Don’t be afraid to experiment and try new things when working on your own models.