If you can use an aerosol can, you can use an airbrush. The two work in the same way, but the airbrush offers a finer spray and more precise control.
Okay, let's look some basic airbrushing skills, then we'll see how it can be used for wagon, building, track and locomotive weathering.
In a typical kit you'll find the airbrush, a few accessories, instructions and a cleaning brush. This airbrush is set in double-acting form, but it can be converted to single-action using the supplied valve.
An air supply is essential. Aerosol cans of air are not really useful unless you need to work portably. They don't last very long and the pressure supplied drops off. Standing the can in warm water helps to even this out a bit.
The choice of compressors can be bewildering, so talk to other modellers and suppliers for suggestions. Left is a cheap diaphragm compressor that is noisy but effective. The other is a Sparmax unit that is quieter, more sophisticated and does everything your likely to require.
The accessories you'll need are paint mixing cups (we used pound shop shot glasses), a stirrer and pipette for transferring paint thinners from the big bottle to the cups, and lots of kitchen towel.
A mask stops you breathing in paint fumes. Do not rely on a dust mask, as these won't stop the much finer vapour droplets. Work outside if you can, using a large cardboard box as a spray booth.
It might seem obvious to suggest how best to hold an airbrush, but we find this basic position is ideal for precision and control.
Mix up some paint 50:50 with thinners and load some into the airbrush. Then spend time spraying bits of paper to see how more/less air and paint mixes appear. Raiding the recycling bin for old plastic packaging isn't a bad idea either to practice on odd shapes.
Learning how to mix paint takes a bit of time. Here, there is a bit too much thinners in the. We are aiming for lots of thin coats rather than a few thicker ones, so this isn't an issue. A hair-drier speeds up the drying process and reduces the urge to lay on a thick coat.
More than anything else, we use an airbrush for weathering models. It's the only way to lay down a nice hazy colour over a surface and the results will generally look better than anything you've done before. The paints are thinned with white spirit at 75:25 thinner:paint.
Start with black, working from above and on the upper sides. The nozzle is held about 30cm from the model while working. If it's a warm day, the paint dries slightly before hitting the side giving a little texture to the finish. If it's cold, a hair-drier is useful between coats.
Bringing the nozzle too close to the model or over-thinned paint can cause runs. A kitchen towel moist with thinners is useful to quickly remove faulty paint. Another advantage of an airbrush is shown here, painting under the walkways is much harder with a brush.
Work the earth colour into the underframe by spraying from beneath. Start on one side of the wagon and bring the airbrush across making sure you go past it. Several passes may be required to build up the level of grot required. Finish with a coat of track colour. Don't worry about letting each colour dry before moving on, they can blend on the model just as in real life.
Adding a bit of dirt takes less than five minutes but the difference between clean and weathered wagons is huge. If you have a trains-worth of models, airbrushing a batch speeds things up. Being able to vary the colours adds a subtlety that can be missing from some factory weathered finishes too.
Ready to plant buildings, such as this Scenecraft Pendon Wash house, look great. For some reason the chimney is squeaky clean, which is not a good look at all.
Mix some black and dark grey paint, add thinners and gently spray around the chimney pot and nearby roof to add realistic soot. Build the effect up gradually depending on the area your model is set. The method works just as well in scratch-built and card kit-based models.
Correctly thinned, you can airbrush with any paint you like. For this piece we used paint from the Lifecolor Rail Weathering set. While it is possible to thin these with water, a better result is obtained using the correct thinners.
Start with a general coat of ‘Sleeper Grime’, since this is supposed to be a grotty siding. Work along both sides of the track as the rail causes a clean ‘shadow’ to form. Pay attention to the prototype too – steam and diesel tracks get dirty very differently.
A mix of ‘Weathered Black’ and ‘Roof dirt’ is applied where a diesel loco has been standing. Once spraying has finished, rub the edge of a wooden lollypop stick along the rail tops to clean them of paint.
Painting a locomotive
Start by spraying all the nooks and crannies. The chimney and dome are worth painting at this point too. We're holding the model on a sprung metal paint handle, but a piece of wood and Blu-Tack will work. Don't try to hold it with your fingers.
Cover the sides by starting the paint with the spray past one end of the model. Bring it along at a constant pace until you pass the other end. Repeat until the coverage is complete. Remember, many thin coats are better than one thick one.
With a little practice, a good quality paint finish is within the reach of everyone. More complicated liveries are harder, but by this point you’ll need some of the many books available on the subject.
One essential chore is cleaning the airbrush after use. The paint is sprayed through a hole less than half a millimetre across, so if any is allowed to dry inside, it gum things up. Start by running the appropriate thinners through the airbrush until it comes out clear. Then repeat using airbrush cleaner. Put a cloth over the end to bubble the cleaner a little as part of the process. If things do gum up, the tool can be taken apart following the instructions and cleaned with cellulose thinners.