Spray paint from aerosol cans is a great way to get finish, primer and protective overcoats on scale model surfaces. When painting small detailed miniatures there are several techniques that help ensure a good coat from any spray can.
General Tips For Safe Effective Spray Painting
- Only work in a well ventilated area.
- Don't spray near any source of possible ignition (fire, spark, heat, electricity)
- Wet the area you will be spraying in down with a light mist of water first to settle dust.
- Use a spray booth, even one made from a cardboard box is better than none, as it will prevent overspray (the drops that don't hit the model) from hitting other surfaces.
- Avoid painting in direct sunlight or humid weather. Both these conditions can affect the speed the paint dries at, which can affect the 'bumpiness' of the surface.
Handling Spray Paint Cans For the Best Coverage
- Ensure your spray paint has sufficient pressure to create smooth coats - warm the can in tap water before spraying to increase the propellant pressure. (Do not warm cans over direct heat, or with water warmer than from a tap!)
- Always shake the can twice as long as you think it needs. Shake it for at least one to two minutes. Spray paint needs to be well mixed so pigment coats will be even across the project.
- Use the appropriate nozzle - nozzle spray patterns can vary widely and specialized nozzles are available in the spray paint section of art supply stores. If you find a nozzle which works well for your spray paint, save it for use on another can. Nozzles can be gently pulled off and twisted or turned onto the stem of a spray paint can.
- Ensure you keep the can of spray paint the same distance from your project at all stages of each spray stroke. Move your arm to draw even 'lines' across your project rather than arcs.
- Don't spray back and forth, you have better control if you always spray across a project in the same direction. Make one pass, start to finish, then go back and make another pass.
- Always keep your spray can moving. Start your spray before you reach your object and end your spray after you leave the surface of your object. Spray paint cans send out different sized droplets just after starting and finishing pressing the spray button.
- Overlap your strokes by roughly 1/3 to make sure you get even coverage across an entire surface
- Always apply a coat to the entire surface during one session, rather than leaving a project and coming back to finish it.
- When you finish a spray painting session, turn your can upside down and spray to clear the nozzle with air alone for five seconds. This will help prevent clogged nozzles.
- Allow spray paint at least ten minutes between spray coats to 'tack up' before you apply the next coat.
Spray Painting Primer Coats
As with all painting techniques, preparation is everything. Follow these tips for priming small items with spray primers.
- If the surface of your model is high gloss, carefully sand it with a fine sandpaper (220 grit or finer) to roughen the surface so paint will adhere better.
- After any sanding, wash and dry your models with a dish soap or with mineral spirits, depending on the material the model is made from. In general use mineral spirits with metal or wood miniatures only, and with enamel paints. For plastics (and wood or metal painted with acrylics) use liquid dish soap and wash and dry the item well before painting.
- Spray primer coats on lightly. You want the details of the model to be left clear of heavy paint coats. Only apply the least amount of primer necessary to help pain adhere.
- Choose a primer which will suit your overcoat / topcoat color. For most miniatures and models, it is quicker to choose a primer color which will act as a base for any areas you want to drybrush, so choose your primer color accordingly. If you aren't dry brushing, choose light colors for under light colored paints and dark colors for dark paints, or where you need to be able to easily see contrast as you add topcoat details.
Avoiding Spray Painting Problems
- Spray in several light coats. Spraying too close will cause runs every time.
- If you spray too far away from the surface of your project, the paint may dry before it hits the surface resulting in 'orange peel' or uneven pebbled coats.
- For a glossy surface with gloss coats, move in slightly closer to the object on the last passes
- If a nozzle clogs, remove it from the tin and clear the slot at the base of the nozzle
- Don't spray back and forth, one pass, start to finish, then spray again from start to finish.
- Always keep the can moving, holding in one spot will add too much paint and you will get a run.
- Press down on the nozzle before you reach your object with the paint, and stop pressing on the nozzle after your spray pass is past your object. This will give you the best chance of an even coat.