The Basics of Airbrush Weathering

By: Eric Siegel

Part 2: Choosing Your Paint

In part 1 of this article, I discussed to equipment you will need in order to weather your trains with an airbrush. In this second part, I will discuss the types of paints typically used in airbrush weathering. In general, there are 2 types of paints you can use for your airbrush weathering jobs: water based acrylic paints or solvent based oil paints. There's no "wrong" choice here. Each type of paint has it's pros and cons.

First, let's talk about water based acrylic paints. The big positive that acrylics have going for them is that they are non-toxic. Remember that an airbrush is creating a fine mist of paint and it's unavoidable that some of that mist is going to circulate around the area in which you are painting, even if you're using a paint booth. Having non-toxic acrylic paints greatly reduces the risk from fumes and requires less protection as a result. Acrylic paints also have the benefit of a very short drying time….usually measured in minutes. This means the time between painting to handling is much less and therefore might appeal to the child-like impatience that many of us train guys have. Finally, acrylic paints are easily thinned with distilled water, which makes for easy cleanup. The downside to acrylic paints is that they are a more fragile than solvent based paints. By that I mean that if you handle a train weathered with acrylics, it's more likely you might rub off some of the paint. This is because acrylic paints do not bond as well to non-porous plastic and metal surfaces as their solvent based oil counterparts. This is why all of the train companies paint their models with solvent based paints and not acrylics. Since all trains are going to be handled on occasion, using acrylic paints for weathering requires the application of extra sealers to insure that the paint stays on the model. There are many companies that make acrylic paints suitable for airbrushing, but most people out there will either use Polly Scale or Tamiya. Most railroad modelers usually chose Polly Scale.

Next, let's talk about solvent based oil paints. The big selling point for solvent based paints is that they adhere very well to plastic and metal surfaces. Once they are on, they are pretty much on for good and will only rub off with extensive handling. The downside of solvent based paints, however, is that they contain toxic chemicals and the fumes created by airbrushing with solvents is very bad for your health. For this reason, extra protection is needed when airbrushing with solvents. You will need to be in a well ventilated area or use a paint booth and you will need to wear a high quality respirator to prevent inhalation of the toxic fumes. Solvent based paints must be thinned with mineral spirits (paint thinner) and cleanup of these paints is a little more involved than their acrylic counterparts. There are several manufacturers of solvent based paints suitable for airbrushing, but the major brands used are either Floquil or Scalecoat paints. My personal recommendation is Scalecoat paints. Scalecoat is sold by Weaver Models and it's what they use to paint their own products.

As for my choice, I weather my trains exclusively with solvent based oil paints. While the extra protection needed when using these paints is somewhat cumbersome, I feel that the end result makes it all worth it. In my opinion, solvent based oil paints adhere to the trains better and just "look" better when it's all said and done. In my upcoming airbrush weathering workshops, I will be demonstrating both acrylic and solvent based paints, but most of the work will be done with the solvent based variety. Don't worry, I will have plenty of protective gear on hand for everyone!

Part 3 of this article will cover painting tips

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