Air Brushing


Unless you have a spray booth, spraying thinner through your airbrush will soon fill a room with noxious fumes. All you need to solve this problem is a 2-litre plastic milk carton and some plastic tubing. Poke a hole in the carton opposite about the bottom of the handle and insert the tubing — a flexible drinking straw is ideal. Make sure that the end of the tubing is at the bottom of the carton then seal around the hole with epoxy where the tube enters the carton. Now fill about one third of the carton with a 50/50 mixture of water and liquid detergent.
After airbrushing, spray any excess paint and thinner through the tubing; the paint and thinner will emerge from the submerged end of the tube creating a foam that prevents most of the fumes from escaping. Additionally, you can put a filter — a piece of old pantyhose or a paper towel — over the mouth of the carton trapping more harmful particulates. Cap the container when you have finished spraying, take it outside, then uncap it and let the fumes escape there. Change the detergent solution occasionally.


File grooves as a rest for your airbrush at one end of a 5” piece of 2” PVC pipe. Drill a ½“ hole in one side of the pipe (for screwdriver access) and a one-eighth inch hole in the opposite side of the pipe (for mounting screw). Bend a 4” long strip of one-sixteenth inch brass or aluminium into a “J” shape. Mount this strip below the ½” hole, then attach the pipe to the side of your workbench. When you are not using the airbrush, coil the airline and hang it up.


Acrylics are an excellent range of paints but can have their own unique drawbacks. They do spray very well but more blockages are likely to occur in the airbrush nozzle than usual. This is probably due to the acrylic pigment being slightly coarser than the more common enamels. To ease the flow of acrylic paints through an airbrush, add just a drop or two of windscreen wash solution to your thinned mixture of paint. The solution is readily available from any motor vehicle accessories shop. Do not go mad with the solution or you will end up with frothy paint — and a very clean model.


Old record players make fantastic painting stands. Place the model to be painted in the centre of the turntable and rotate it by hand as you paint. It works just as well for hand painting as well as spray painting.


Trying to airbrush enclosed freight cars such as covered hoppers, tank cars, box cars as well as passenger cars can be a real challenge because it is difficult to hold onto the shell while painting. This jig makes it easy. The coathanger wires simply slip into the truck-mounting holes on the car. Make the wires long enough so that you can paint the underside of the car without leaning it over. You can adjust the length of the jig by rotating the wires at either end. You may want to build a couple of jigs in different lengths to accommodate various sized cars.


A cheap cake icing turntable or “Lazy Suzan” revolving condiment tray can serve as a useful base for a model while airbrushing. Revolve the turntable for a different angle of spray — this avoids the need to touch the model.


When you are finished spraying with a spray can you have probably been taught to turn the can upside down and spray a short burst to clear the nozzle of paint. This does not completely clear the nozzle and particularly if you are not going to be using the spray can again for a while, it can clog up. Remove the nozzle and soak it in thinner to dissolve any paint still left inside. You don’t have to replace the cap immediately as the paint or propellant in the can will not escape. Just leave the cap in the lid until you are ready to paint again and after fixing the nozzle in place, you will be able to spray with a nice clean nozzle.


Painting from spray cans can produce great finishes but you don’t have the same control with a spray can as you do with an airbrush. You can either mix the colour to try and match the spray can colour you want, or you can download the paint from the spraycan into an airbrush jar. In this way you get the exact colour you want. Simply attach a short section of a plastic drinking straw to the spray can’s nozzle with tape making sure that the orifice is inside the straw. When spraying into the airbrush jar, place the straw against the opposite side of the jar, levelling out the jar as it fills. You don’t have to thin the paint that comes from the spray can, it is ready to use in your airbrush.


A good material for masking is frisket paper or frisket film. This is a thin, paper backed, self adhesive material used by artists to mask airbrush illustrations. Cut it to the desired shape, stick it in position and burnish the edges with your finger nail to stop paint bleeding underneath.
Another art supply product for masking is drafting tape. It is similar to masking tape but the adhesive is less sticky. Whatever material you use for masking, it should be removed as soon as possible. Masking and transparent tapes become harder to remove the longer they are left. To reduce the amount of adhesiveness on masking material, stick them down on a sheet of glass first then onto the material you are masking.


It is a tedious job painting rust colour on the sides of track with a brush and it is much faster to use a spraygun. However, sleepers will need to be masked and to keep the rail heads clean and shiny, apply a light coat of oil with a piece of soft cloth on the tip of your finger. Take care not to get any oil on the sleepers or the sides of the rails. Keep the spraygun low so that only the sides of the rail are painted. After spraying, all you need to do is use a track cleaning rubber along the railheads to eliminate to paint from the spray.


The soft-bristle brushes designed for cleaning between teeth instead of waxed dental floss, are ideal for cleaning airbrushes. Check with your dentist. There are a number of various brands and they have a holder which the brush pushes into. You will find a number of uses for these small brushes around your modelling workbench.


Spray paint from cans flows better, particularly in cold weather, if the can is soaked for a few minutes in hot tap water.


Wear a large plastic trash bag – with arm and head cutouts – when spraying paint. It will not only keep the paint off your clothes, but the static cling of the plastic will attract dust that might otherwise end up on your freshly painted model.


Despite following the instructions on spray cans which say to turn the can upside down and press the nozzle to clear it of paint, it does not always work and some nozzles can remain blocked. A trick is to wipe the nozzle after spraying and push a short length of approximately 45mm wire into the hole on the spray head. Try florists wire, finding one size that is a perfect fit. Leave the wire there between sprays and the hole should remain clear for the next spray assignment.



If you thin paint for use in your airbrush, do not return any unused paint to the original container as this will cause all the paint to go lumpy and eventually solid. It pays to discard this leftover thinned paint as adding thinner to paint certainly allows it to flow through the airbrush, but the balance among pigment, vehicle (thinner) and binder gets out of kilter and chemical changes start to occur. This is quite OK for the paint you use on the model but the paint in the container separates over time forming a rubbery gel between thinner and pigment making the paint unable to be remixed. Discard all leftover thinned paint.


It is possible to spray enamels, lacquers and clear coats over completely cured acrylics, but each brand may behave differently. Never apply a heavy wet coat of anything over a dry or cured coat as you could risk having the new wet coat eat right through the new wet paint. You should build up light, quite dry coats and you should be safe.


If you have had trouble thinning water-based paints such as Polly Scale with their recommended thinner, try using distilled water, or use a mixture of 1:1 Poly Scale clear gloss and water as the thinner. The addition of clear gloss will make the paint spray with less clogging.


If you airbrush in a spray booth, overspray can build up on the walls over time and decrease the reflected light from your work area. Visit your local newspaper and get the left-over core of a newsprint roll which usually has quite a bit of blank white newsprint left on it. Cut several pieces to fit and tape them to the walls of your spraybooth. Change them regularly to keep clean white reflective surfaces.


A useful lubricant is that which band musical instrument players use to keep the valves on their trumpets and other brass instruments moving freely. Add a little to your air brush after cleaning and you are ready to paint next time with no sticking