Getting Started with Airbrushes

Firstly, I’m not even going to attempt to discuss the options available when purchasing an airbrush. Just went into our local art supply shop and bought a Testor’s Aztec 4709 airbrush set and a pretty good air compressor. Everyone has there own preference, so I’ll never know unless I buy another brand whether or not it was the right choice. But if you’re in the process of deciding, get a double-action brush – it’s a must if you want to be able to quickly make adjustments to the type of spray as you work, it gives an interactive tangible feel that can really improve your results.

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Now, even after reading pages of airbrush information on the Internet – with all the warnings on how easy it is for the airbrush beginner to get discouraged – the first days were really really frustrating. Having read the instruction sheet & watched the video a few times, I thought things looked straight forward enough – but like most things in life, theory and practice are all too different.

The main issue is the number of variables that come into play when attempting to set up your brush. These variables can be classified into 3 groups:

This in itself does seem pretty straight forward – but it’s the balance of these elements relative to your requirements that can be so difficult to master. The degree that each of these variables can be adjusted means that there's not much between getting it right and getting it wrong - hence defining the set-up for the novice difficult.

What I’ll try to do is document how I personally got from complete novice to successfully completing my first spray-painted model – it may not be expert advice – just how I got the confidence to start working on a model.

I’ll assume that the equipment is working ok and you’ve got to the stage of spraying a water based paint onto scrap paper (artist water colours are perfect for this). Make sure you understand how to correctly setup your brush. For example, with the Aztec, if you don't have the nozzle tightened enough, it effects the airflow and results in a poor spray quality.

Rather than trying to explain the theoretical properties of the various combinations - what in my opinion makes the learning process so hard - I’ll show the consequences of getting these combinations wrong. This may give the beginner a better understanding of how these various elements can effect the results you get.

note: There’s a free guide to download from the Testors web site. It’s on model making in general, but includes as you’d expect, a section on airbrushing. I came across this at a crucial time in my learning process – it confirmed what I was beginning to learn from experience, and represented visually in an easy to understand way. I’m not here to endorse their product’s or anything like that, but they do deserve credit for taking the time to ensure that their customers understand the equipment. (URL is on the Links Page)

I think its easier to display the effects of an incorrectly setup brush, and work back to the cause – this will allow you to take the necessary steps to avoid problems. Its important to mention the consistency of the paint. I don’t think others indicate how vital it is to develop an understanding of the paint you are using. Getting the same consistency each time is difficult to achieve – but knowing when to compensate to avoid poor results is important. People tend to forget that the paint is the key ingredient in airbrushing, hence requires the most attention. Pressure and proximity are key elements in their own right, but they act on the paint - not the other way around.

Too close

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This effect (normally called spidering) is caused when either the paint is too thin and/or the airbrush is held too close to the model. To correct it - move the airbrush away from the surface of the model. But, if you need to keep a fine line, reduce the pressure on your compressor. Alternatively, you could thicken the paint slightly if you want to keep using the same air pressure.

Paint too Thick
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This is normally caused by low air pressure from compressor. But again, you could argue that its a consistency issue, with the paint being too thick, and the low pressure being insufficient to atomise the paint.

To solve this problem; Thin the paint and/or increase air pressure.

Paint Too Thin
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You get this result if the paint consistency is too thin. To fix it,  add more paint and/or decrease the air pressure.


These problems seem to be magnified when working on hard plastic surfaces. I didn’t have any spare models lying around to practice – but any old plastic container will do.

To sum up: if you find that you are unhappy with the quality or definition of the edge of your spray line - the chances are that the paint is too thick. You need to thin it down and back off on the air pressure. Most describe a milk-like consistency. Well this is normally hard to visualise inside a cup of mixing container - quite often you can go quite thin. Remember, if the paint can't atomise the paint well, its going leave the nozzle too thick, and not in the fine mist needed for smooth edges. Backing off on the pressure also reduces the speed and volume of paint delivered to the nozzle - this means that you don't have to work as fast, and that you can work closer to the surface -  hence allowing finer lines.

I know its taking the easy way out, but I'd suggest working on a 1/25th scale kit (I did a Jadgpanther). Working with the larger scale really does allow the beginner a margin of error that you simply won’t get with a smaller model. For example, when I sprayed the camouflaging lines, there was too much overspray at the edges – but by working at a larger scale, I could fit a smaller nozzle, and redefine the edges. If you prefer, work on a scrapped model first, you can still go ahead and get a larger scale when you get the confidence.

Having worked on a number of models larger than 1/35th, have to say I find quite a difference on how you handle the airbrush. With 1/35th you have to work more instinctively - there's less time to build effects up compared with 1/25th or 1/16th. An airbrush really does come into its own at these scales. No doubt in time, I may evolve my skills to work in the smaller scale's - but I'm starting to develop a strong preference for large kits. Of course this has a number of draw-back's - price & range to name but two. But in terms of the finished article, frankly 1/35th kits just don't have the same presence.

Back to the airbrush. Using double action will allow you to adjust the response of the brush on-the-fly. Backing off on the amount of paint delivered to the nozzle is crucial to adjusting the spray pattern.
You really have to keep faith - it just seems to fall together - you just need to be patient. I'm a long way from being expert - but went from despair to reasonably confident  once I acquired the essence of controlling the set-up. Sorry I can't be more specific - but it really is a state of mind more than anything.

Good luck.

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