Airbrushing an RC body

Spray cans cover a shell. An airbrush lets you draw on it: fades that run the length of the car, shadows under a stripe, drop shadows on a number, a custom colour mixed in the cup. The rules of polycarbonate painting stay the same, inside the shell and dark before light. What changes is how much control you have.

The kit

• A dual-action, gravity-feed airbrush with a 0.3 to 0.5mm nozzle. Dual action means you control air and paint separately with one trigger, which is what makes fades possible.
• A compressor with a tank and a moisture trap. The tank evens out the air so the spray does not pulse.
• Polycarbonate airbrush paint and the matching reducer.
• Airbrush cleaner, pipettes or mixing cups, and paper towel.
• Liquid mask and fine line tape. Airbrush work nearly always means more masking, not less.

Thinning and pressure

Paint for an airbrush should be about as thin as milk. Some airbrush paints are ready to spray from the bottle and others need reducer, so check the label and use the reducer from the same range.

These are starting points. If the paint spits or looks grainy, it is too thick or the pressure is too low. If it runs or spiders out from the centre, it is too thin, too close or too much paint for the air.

Technique

1. Air on first, air off last

   Press for air, then pull back for paint, and release paint before you release air. That stops the splatter at the start and end of every stroke.

2. Keep the airbrush moving

   Start the stroke off the area, sweep across and finish off it. Paint builds where the airbrush pauses.

3. Build colour in thin passes

   Polycarbonate airbrush paint dries quickly in thin layers. A hair dryer on low between coats speeds it up. Thick wet coats take a long time to dry inside a shell and can lift when you mask over them.

4. Dry each colour before masking over it

   Touch dry is not enough for tape. Give it a few minutes with the hair dryer, then let it cool.

5. Back it, as always

   Airbrushed coats are thinner than aerosol coats, so backing matters more. White or silver, then black. Backing with aerosol cans over airbrushed colour is common and quicker; test the combination on an offcut first and let the airbrush colours dry fully.

A first fade

1. Spray the darker colour from the front

   Full strength at the nose, then pull the airbrush further away as you move back so the colour thins to a mist around the middle of the shell.

2. Spray the lighter colour from the back

   Full strength at the tail, misting forward into the dark colour. The overlap is the fade.

3. Check from the outside

   Turn the shell over and look through the plastic as you go. That is the view that counts.

4. Back with white, then black

   White first keeps the fade bright and even.

Cleaning

Flush the airbrush between colours and strip the needle and nozzle at the end of the session. Dried paint in the nozzle is the cause of almost every spitting, pulsing airbrush. Never leave paint sitting in the cup while you mask.