Tools and Techniques
August 7, 2016
Given that I’ve spent the last month (or longer) painting the Bluenose, it would seem fitting to spend some time talking about airbrushing.
I try to do as much of my painting as possible with an airbrush (as opposed to hand painting). The main reason is that I’m awful at hand painting, but I also feel that airbrushing gives a better finish.
Getting started with airbrushing can be intimidating (it was for me), but after a few rounds of painting, it gets really easy.
There are a few things to consider when it comes to airbrushing…
Let’s start with the airbrush. An airbrush is a fairly simple device. It takes air from an air compressor and sends it through ‘tube’ where it hits some paint, and sprays it out through a small nozzle. The force of the air turns the paint into a mist, which is blasted onto the part you’re painting.
Since the paint is a fine mist, you get a much smoother, cleaner finish. I find it easier to get large areas covered smoothly. There are no brush strokes visible. The airbrush also makes it easier to get tiny details filled in. Perhaps most importantly, the thin mist of paint doesn’t ‘build up’ like hand-brushed paint does.
When picking an airbrush, there are two main ‘features’ that you need to pay attention to. First, how is paint fed? Some airbrushes use a cup on the top of the airbrush. You pour paint in, and gravity does the rest. Others use a ‘siphon feed’, where you put paint into a special container, and the airbrush pulls paint up through a tube. I’ve always used gravity fed cups. I don’t want to mess with cleaning out a siphon tube every time I use the brush or change colors. Also, you’ll find that you don’t actually use that much paint, so I rarely need so much that I need to fill some container. I typically fill my cup only about 1/3 full for most jobs.
The second feature to pay attention to is ‘double action’ vs. ‘single action’. This determines how much control you have. On an airbrush, the inputs are air and paint. A single action brush controls just the air – the amount of paint fed into the system is constant. A double action brush lets you control air and paint. This gives you more control, but it takes a little longer to get used to. I use double action airbrushes. On mine, there is a lever that you push down to control airflow (further down means more air), and pull back to control paint (pull it further back to get more paint).
I’d recommend a double action, gravity fed airbrush.
My current airbrush is a Paasche Talon. There are a number of things I like about this brush. It has a very solid all-metal construction. It disassembles easily for cleaning. On the rear of the handle, you can tighten or loosen a knob that lets you control the maximum travel of the lever (thus letting you limit how much paint you start spraying).
Another great thing about the Paasche Talon is that you can get it with a set of tips. I got the set without realizing it, and halfway through painting my Bluenose, I discovered the other tips. It was life-changing. The Talon comes with 3 tip sizes. One is for very fine details (like lines). Another is a general purpose, is what I used for about a year without realizing it. The third is a wide tip, that sprays in about a 3″ wide ‘fan’. This wide tip made all the difference when painting the hull. It let me easily and quickly get an even coat across a large area. I strongly recommend getting the set with the additional tips.
To get air to the brush, you need a compressor. I honestly don’t know much about compressors, the one I use came with a cheap airbrush set I bought online. (The actual airbrush from that set quickly died.) If I were buying another one, I’d look for something that was decent quality (mine sometimes overheats and shuts down for a moment to cool off). Look for something with a moisture trap (usually a glass tube somewhere on the compressor). You’ll want something that can push at least 20 psi, which any inexpensive compressor should be able to do.
I envy people who have a workshop and can dedicate space for painting. I don’t have that luxury. I do all my airbrushing out the garage, and I typically have to move the cars out. Most of my painting is done using a paint hood that I bought. This is a small box that opens up to give you a small space for painting. It has fans on the back, and keeps all the mist and such from blowing around.
The Bluenose was too big to fit under my paint hood, so I ended up doing all the painting in the middle of the garage. I set a cardboard box on top of a small work table and started spraying. This worked well because I could move around all sides of the ship while I painted.
Regardless of where you do your painting, you need to wear a mask. Airbrushing turns paint into a mist, and it quickly gets out into the air. Some paints, like enamels, have lots of chemicals in them. You don’t want to breath that.
I use a mask that I bought online. I think when I first bought my airbrush set, Amazon listed this as something other people bought. It has held up well.
I also use thin gloves when I paint – it is just easier than trying to keep paint off my hands. I buy these gloves in boxes of 200, and it takes me a couple years to go through a box.
So, you’ve got an airbrush, connected to your compressor, and you’ve got a space set up to paint. But what paint?
When I first started researching paints, I found a lot of conflicting information. There are paints labeled as being specifically for airbrushes. Their are enamels and acrylics. There is a lot of talk about thinners.
I use exclusively acrylics. The big difference between acrylic and enamel paint is that acrylic is water-based, while enamels are more chemical based. Acrylics are typically thinner to start with, and I’m able to use most acrylics right out of the bottle without thinning. When I do thin, I can do it with water instead of some specialty enamel thinner (which is something I imagine you’d always run out of at the worst possible time).
Thinning…paint needs to be pretty thin to get through your airbrush. If it is too thick, it will quickly clog up. It should be about the consistency of milk, which is always tough for me to gauge. I just try to make sure the paint looks pretty thin.
Most of my painting is done with Testor’s Model Master paints. These are widely available and they come in a ton of colors. Their acrylic paints are thin enough to use in an airbrush without additional thinning. I’ve also done some with Humbrol paints, but these do require thinning (I tried Humbrol without thinning, and it clogged the brush every time).
For priming, I use Tamiya Liquid Surface Primer. The primer is lacquer based, and it needs to be thinned. Tamiya makes a lacquer thinner for this purpose. I use a mix of about 1 part primer to 1 part thinner.
I try to always get a good coat of primer on before I paint. It results in a much smoother finish. I typically do multiple coats of primer, and I sand it down between coats. During priming, I often start sanding with a 150 grit paper, and work my way up to 800 grit.
When painting, I often apply 3 or 4 coats. Apply the paint lightly, and don’t try to get a nice thick coat each time. If you spray too much on at once, it will start to pool and run. My first couple of coats often look splotchy, and don’t seem like they are producing a smooth even finish. However, the 3rd and 4th coats even everything out. Between paint coats I typically sand with 800 grit sandpaper.
When applying paint, you want to use slow and steady passes over the part you’re painting. Start your airbrush spraying off to the side, so it is spraying before it hits your model. (When the brush first fires up, you often get a ‘burst’ of paint, and you don’t want that to result in a spot on your model). Spray straight across off the other side of your part, then reverse direction for a second pass. Do not try to go back-and-forth while your airbrush is over your part – that split second where you’re changing direction will cause a spot of paint to build up.
For large areas, like the hull, I typically give one side of the ship a good quick coat, then turn the model and paint the other side. During that time, the first side dries enough that I can give it another pass. I’ll do this 3 or 4 times, then shut everything down and let the paint dry for a couple hours – this is my first coat. After a couple hours, I sand, and repeat the painting process. I do this whole thing 3-4 times minimum.
With airbrushing, it is important to mask off anything you don’t want to get paint on. I find it easier to spend half an hour covering things with tape so that I can just spray paint everywhere. For masking, I use Tamiya tape.
From time to time, I do end up thinning paint a bit. Sometimes I’ll use a thinned coat as the final coat since I won’t be sanding it. When thinning, I could use water, but I normally use an acrylic thinner. I put some paint in a cup, squirt in a little bit of thinner, and mix. Some people get really particular about thinning ratios – I just squirt a little thinner in. I bought a bunch of disposable plastic measuring cups for mixing, and I use coffee stir sticks to mix.
The most annoying part about airbrushing is cleaning. You have to clean the airbrush any time you are going to set it down for more than about 5 minutes, and every time you are going to change colors. The thin, misted paint in the brush will dry quickly if you don’t clean it right away.
When I’m doing multiple coats of the same color, I’ll do a ‘quick clean’ every time I finish a coat. I dump any unused paint back the bottle (only if you haven’t thinned it). I rinse out the paint cup using water and a sponge, and clean off any paint I spilled on the outside of the brush. Then I fill the paint cup with water, and run the airbrush until it is spraying clear water.
Note that this only works if you’re using acrylic paint. Since acrylics are water based, they clean up with water. If you’re spraying primer or enamel, you’ll need to use the appropriate thinner/cleaning solution to do your cleanup.
When I’m done using the brush for a while, I give it a more detailed cleaning. I remove the tip, the handle, the needle, and the trigger spring. Each part gets wiped down. I use a thin brush to clean inside the airbrush. This gets inserted in the back of the handle, and follows the path of the needle.
Overall, I find painting with an airbrush to be very easy. I certainly feel like I can get much better results than I could with hand painting. I also love the shorter drying time (since the paint goes on so thin, it dries much faster!). The only downside is the extra work to set up and clean up the airbrush, but it seems worth it.
The best way to get comfortable airbrushing is to just dive in. You can’t really do much damage – the paint goes on so thin that if you aren’t happy with it, give it a quick sand and paint over it again!