Benefits abound for using wood: It gives a sense of natural sturdiness and has an aesthetically pleasing appearance. However, wood isn't always a practical building material, as it can crack, chip, fade and rot. In fact, sometimes plastic is a preferable material, particularly if your structure will have constant exposure to the elements or if, as an environmentalist, you object to the process of cutting down trees. Luckily, you can paint your plastic items so they have the look of wood and the ruggedness of plastic.
Put on protective eye wear and gloves. Go outside or to a well-ventilated area. Spray your plastic pieces with light grey latex primer. Make even back-and-forth movements with your can of spray primer. Allow the primer to dry completely.
Airbrush acrylic brown paint on the plastic, coating it with a very thin mist. Some of the grey should show through. Allow the paint to dry for around 20 minutes.
Rub a 3-inch-wide fibreglass brush against the paint, removing some of the brown you just sprayed on. Be careful not to remove any of the grey primer. Do this to the entire surface area.
Airbrush a light coat of acrylic paint in a medium tan colour on the plastic object until you cover it with a light coat of colour. Allow it to dry completely.
Scratch off some of the tan colour, using your fibreglass brush. Again, do not remove any of the grey primer underneath. Continue in this fashion until you have worked over the entire surface area.
Airbrush a light coat of charcoal coloured acrylic paint on your plastic item. Allow it to dry thoroughly for approximately 20 minutes. Rub off some, but not all, of the charcoal colour with your fibreglass brush. Now your piece of plastic should look like unpainted, slightly weathered wood.