Almost the last word in choosing an airbrushes

 I’ve entitled this piece “almost the last word in choosing an airbrush.” The reason for this is that someone, or quite a few who read this are going to have a lot to say about this article. Choosing an airbrush is a personal thing. What works for one person may not work for another. However, there are some basic rules that should be considered when you buy an airbrush together with some basic science.

I’m a modeller! I use my airbrushes on a daily basis. I’ve tried most of the airbrushes out there and I would like to believe that I have a good understanding about the pitfalls and the pain when buying an airbrush. I have been there and done that. I spend a lot of time talking to modellers from various backgrounds and at different skill levels.

As an authorised Grex dealer. I make no bones about the fact that the Grex TG is my preferred airbrush. When I came back to the modelling hobby I started with the typical cheap airbrushes in the “blue foam” box. I also bought a very cheap compressor which I returned within a week and exchanged it for a similar model which had a tank. After a lot of frustration, I very quickly moved on to buying an H & S Evolution and a high end Iwata dual piston compressor. Admittedly the compressor was a little bit of an overkill.

After this came the Aztek A777 metal airbrush. If it was favoured by someone like Brett Green I couldn’t go wrong. It was at this point that my airbrushing started to come close to what I was trying to achieve and what I saw others achieving in their models. There was nothing spectacular about the Aztek. What had changed was the fact that I’d gone from .2 mm needle to .3 mm needle unknowingly

Beginners struggle with the concepts of paint thickness as described in a lot of modelling articles. People talked about “thinning your paint until it has the same viscosity as skimmed milk”. When you are at the workbench and pretty new to airbrushing the statement means nothing to most people. Getting good results with an airbrush requires three settings: paint, viscosity (paint thickness), needle size and PSI (compressor air pressure). The type of paint you use will also have a dramatic effect on the results that you achieve.

Using a .3 mm needle does not mean that you cannot produce fine lines. One of the features I like about the Grex is that you can regulate the trigger travel and air flow to the point where you constantly get the finest of lines.

A modelling friend says he can write a signature with these Grex. The reason that he can do this is that Grex has engineered their needle to work with model paints. It has a slightly design to it. I will come back to this.

Illustrators and beauticians use inks or high gloss nail polish. Not model acrylics or enamels. Paint has a completely different viscosity and is thicker than ink. That is why people still struggle with high-end airbrushes from other manufacturers. Don’t get me wrong, if I someone asked me what’s the best airbrush to buy for illustration I would absolutely recommend that they consider the high-end Harder & Steenbeck CR plus or something similar from Iwata or any one of the leading brands.

Having owned a H & S CR Plus one and it’s an amazing airbrush. There is a BUT. When it came to modelling I didn’t get the results that I wanted. The .2mm needle was too small and the .4mm needle to big. I found myself limited to the types of paint that I could use. These were mainly Mr Hobby and Tamiya.  These paints worked well because by this stage I’d learned to thin the paint down to about 65/35  ratio mix of thinner (reducer) to paint. The moment I tried something like Lifecolor which has a very grainy and chalky consistency I found that my very expensive H & S began to splutter. It was not the airbrushes’ fault but it was the needle size. At this stage are still owned by Aztek and I found that I had no problems Lifecolor or Valljeo through it.

I also found that I struggled to pre-shade.   When doing something like a Spitfire with a lot of panel lines I found that my hand would cramp after a period of time. More importantly, most of my pre-shading disappeared once I started with my topcoats. The reason for this was that unless you use Mr hobby in an almost translucent (very thin) state and let it dry between coats, you will very quickly lose your pre-shading lines.

Having read a lot about the Grex pistol grip and watched a number of Youtube videos I hoped that it would at least solve the problem of hand cramping. I wanted a high-end airbrush as I felt that I’d outgrown the Aztek and I was disappointed that I was not getting the results that I wanted with the H&S.

The moment that I started using the Grex TG .3mm I felt that I was now using an airbrush designed for modellers.

People complain that they tried an airbrush at a modelling show and that it performs completely differently when they get home. Why? The first question is “did you actually try the airbrush with the paint that you intend using at home? The answer is usually “No I sprayed whatever was available at the show”. Model paint is expensive and generally people demonstrating airbrushes at shows use food colouring or a very thinned ink. This is not to try and trick you it is simply economics.

Beauticians who use airbrushes to perform nail art will also prefer the .2mm needle because they are using gloss pigments (nail polish) which again flow more easily through the airbrush than do the flat military colours that we as hobbyists generally use. It’s important for model builders to understand that most high quality airbrushes are engineered with inks and gloss pigments in mind and not the flat paint qualities that model builders use on a regular basis.

Let’s pause a moment Flat or Matt colors use in military modelling lacks shine (gloss) high gloss paint finishes reflect light and that is not something that is desirable when try to hide from an enemy. In fact for most military modellers they use a clear flat coat as the last sealing coat to get an even flatter finish.

So what makes an acrylic paint Flat? The coarse molecule of the paint is what gives it a flat look and consequently increases the viscosity and this presents further inherent challenges of the paint flowing through the airbrush as compared to gloss paints and inks.

While it’s possible to utilize the .2mm needle and nozzle combination for model building it does have limitations that could become challenging to the novice airbrush user. To begin with, most hobby paints, whether they are enamels or acrylics, require some amount of thinning to work in an airbrush. The range of proper thinning is very narrow when using a .2mm needle. If the paint is under thinned, then the paint will tend to spatter rather than provide a smooth flow of paint when attempting fine line work. If the paint is thinned too much then the paint ceases to perform as it should. It could become translucent when it should be opaque. The paint may not bond with the surface of the model properly either and easily buff or chafe off. Masking over it may also cause the paint to lift off the model as well.

If you prefer to use acrylic paints specifically more problems could occur. For example, tip dry is a constant problem for most water-based acrylics. The smaller needle size will likely exacerbate the problem more. Also in regard to acrylics, even if the paint is thinned correctly, there is the possibility of an unusually large particulate of pigment in the matrix if the paint that can cause clogging issues as well.  Going from a .2mm needle to a .3mm needle may sound like semantics but trust me, it does make a difference and will reduce or eliminate these problems.

So you may ask, how does the .3mm needle still provide a fine line quality yet be a bigger needle size? As I mentioned above,  the Grex answer to that is in the taper of the needle itself.

Many of Grex’s competitors have what I call a compound taper to their needles. That is to say the needle tapers for a bit then it has a more extreme taper to the point of the needle. This can be seen if the needle is held against a white background showing the profile of the needle. While this type of engineering creates strength in the needle it compromises performance when it comes to detail work. If you look at a Grex needle it has one extreme taper that is consistent from tip to the full diameter of the needle width. Grex Airbrush needles are made of stainless steel to maintain integrity. However even with a strong metal such as stainless steel we recognize the needle can still be damaged. With that said Grex do no not charge an arm and a leg for a replacement needle to the consumer. Dealers offer replacement needles for around £10.00 or $12.00 give or take a few pence/cents.

As such with the .3mm needle in conjunction with our fluid nozzle engineering a fine line capability is easily obtained with less precise thinning of the paint. Practice and knowing the qualities of your preferred brand of paint are still necessary however the likelihood of success is much greater. With regard to water-based paints, tip dry is still an inherent issue but at a reduced level.


With all that has been said, I can say with confidence to the novice airbrush user the .3mm needle is a much preferred needle size to that of the .2mm needle.  My suggestion to the consumer is to start off with an airbrush with the .3mm needle in it. If at some point with experience they wish to change the needle size they may do so.

Grex Airbrush does provide TK-2, TK-3 & TK-5 nozzle kits, which are comprised of three components, the needle, fluid nozzle and nozzle cap, which are matched for the best performance possible. The TK kits are compatible with Grex Tritium TG and TS airbrushes as well as our new Genesis XGi and XSi airbrushes. The suffix number denotes the needle size in the kit, .2mm, .3mm or .5mm.

Should the airbrush user wish to go down in needle size or go to a larger needle size for larger projects they have the capacity to do so. These kits retail for around £27.00 or $34.00.

Grex offers the pistol grip style (TG Range) or the conventional airbrush with and ergonomic moulded cover that can be removed (XGi Range) both in a gravity feed or a side suction cup feed. The added bonus is of course the ability to use a Fan Cap for those really big projects, but that’s the subject of another aticle.

Lastly, the TG annexe XGi range use a combined double action method for their trigger. The more you pull back and the press/depress the trigger means that you get more area and paint. I found that this allows me super fine control. Been able to regulate the travel in the air with the adjustment knob

When people ask me if Grex provide a start to get the answer is yes, if I start to kit you mean everything to get you started – the airbrush, the compressor a DVD, the hose a variety of cups and a sample bottle of paint. If I start to get you mean cheap then the answer is ‘no’.

There’s an old saying buy cheap by twice. I spent a lot of time talking about needle size and I’m grateful to Bryant Dunbar for sharing his time and knowledge and for allowing me to use portions of his article.

Sean Middleton

October 2016

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