Airbrush Paint Guide
Selecting The Paint That’s Right For Your Work
An airbrush can be used to spray almost any medium as long as it has the consistency of milk. Paint, commonly used with airbrushes, can be defined by five general headings; Watercolours, Urethanes, Oil Paints, Inks and Dyes and Acrylics. There are many brands of paint all offering slightly different features and, possibly, more suited to a particular application.
Watercolours were the first type of medium to be used with airbrushes as they offered the perfect characteristics. They are easily thinned (reduced) by water and do not clog the head of the airbrush as easily as other mediums. Watercolours are also easily cleaned from the airbrush simply using soap and water.
Unfortunately the characteristic which make watercolours perfect for use in an airbrush (excellent thinning and reduction by water) makes them non durable. If left unprotected the pigments, within the paint, can be affected by moisture within the air.
You can, however, protect your work by airbrushing an acrylic varnish or fixative over the top.
Watercolors are described as transparent and are available in three types: Block, Liquefied and Tube.
Block watercolours are hard compressed blocks of colour pigment which need to be worked with water and a paintbrush and then transferred to a suitable pot or similar. These types of watercolours are most suited to when only a small amount of paint is required.
Liquefied watercolour is already thinned (reduced) to the required consistency and can be used straight from the bottle. Many of the present day liquefied watercolours are transparent and water soluble, however, they are more like a dye than a pigmented watercolour. This type of water colour is preferred by illustrators as they are quick and easy to use.
Tube watercolours are most commonly used with airbrushing. A small amount of paint can be squeezed from the tube and mixed with water, in a suitable vessel, to the required consistency. The reduced paint is then simply poured into the paint cup or jar of the airbrush.
Gouaches are an opaque version of watercolours as they contain a higher level of white paint. They are still great to use through and airbrush but, because they are thicker, less coats are needed and mistakes are more easily covered.
Of all the paints, available for airbrushing, Urethane paints are possibly the most durable and are most suited to applications including work on boats, motorbikes and cars etc. They are highly durable and will provide excellent resistance when exposed to the elements, further protection can be provided when the project is given a clearcoat. The reason that urethanes are very resistance is that they contain more pigment, when compared to lighter-weight acrylics.
Urethanes are available as single stage or two stage.
Single stage urethanes combine the pigment with a clearcoat which removes the need for a final finish coat. These single stage coats take a while longer to dry, however, they can be polished and sanded once the paint is dry.
Two stage urethanes do not have a combined clearcoat, as with the single stage urethanes, and will produce a duller finish. Two stage urethanes offer a greater range of colours and include opaques, pearls and transparent. The final step is to apply a clearcoat which provides the lustre and shine.
*Urethanes contain VOCs (volatile organic compounds) which are hazardous to the lungs and other major organs. Ensure that you use a respirator and good ventilation to reduce exposure.
Oils and Enamels
These are some of the more tricky paints to use through an airbrush as they have to be correctly reduced/thinned to ensure workability. This reduction can be achieved by adding turpentine or mineral spirits at a ratio of 60 paint to 40 thinner. Your airbrush will not spray properly if a correct consistency is not achieved and will lead to clogging and spluttering.
Inks and Dyes
Inks and dyes are another type of medium which are excellently suited for use with an airbrush as they are a thin paint and, as such, require a much lower air pressure than paints such as topcoats, candy and pearl. Many inks and dyes available do not require thinning and can be sprayed straight from the pot. Food grade inks are available in a huge range of colours and can be airbrushed onto cakes to create base coverage or intricate design work.
Dyes, as used in leatherwork, are similarly suitable for use with an airbrush to create affects such as sunburst for a worn or darker outer edge with highlighted central relief areas.
Acrylic paints are the easiest and most flexible for airbrushing in so many different disciplines. They can be used to spray almost any surface and have been developed for use with canvas, fabrics and acetates. Acrylics offer a reduced drying time and spray evenly through an airbrush. Acrylics can be over reduced to give a transparent affect and some brands now offer ready mixed transparent paint.
Acrylics should, as with many other paint types, be thinned to the optimum consistency; some are pre thinned but most are not. A suitable thinning agent should be used to prevent clogging of the airbrush tip. If small bubbles appear in the paint cup then this is an indication that the airbrush tip is or has become clogged.
Soap and water can be used to effectively clean acrylic paints from your airbrush. They are also low in toxicity (VOCs), waterproof and colourfast when dry.
Would you like more information about Acrylic v Enamel Paint?
Head over to Model Space to read their blog post on Scale Model Basics: Acrylic Vs Enamel Paint