Airbrushes & Compressors
by Phil Novak
PART 1 The Air Source
So you’ve been thinking that using an airbrush to paint your models may be the best way to go. Well, You’re right! You can spray any color you want, to any opacity, anywhere you want, with total control and finesse. Many modeling techniques and finishes almost mandate their use.
Color modulation, camouflage patterns, glass smooth car finishes, thin layers of dust on vehicles, etc., are all squarely in the airbrush realm. However, if you’re new to all of this, the sheer number of options and choices can be overwhelming. Some people swear by one product or brand, while others clearly state you should use something else.
I’ll attempt to clear some of the waters here, by not recommending anything. (well mostly) “What!?” you ask, “then why am I reading this?! Isn’t this supposed to be about what airbrush supplies to buy?” Well, yes, and no. The thing is, I don’t know exactly what uses you have in mind, what your budget is, and what types of paint you want to spray. All of this makes a big difference, so what I’ll attempt to do here is give you an overview of options, let you know what the strengths and weaknesses are, and let you make the call based on YOUR needs.
What works for one guy may not be the best for you. Knowledge is power, and I know how it feels to waste your hard earned money on something that doesn’t work as advertised (how do you think I learned some of this?). Hopefully, I made the mistakes so you don’t have to! I’ve been airbrushing models for the better part of 20 years, and airbrushes have almost become my hobby within the hobby – so let’s get you off on the right foot!
First thing’s first. An air source. Really, you should work this out before even looking at airbrushes. It tends to be the most expensive part of the equation, and can actually be the hardest part to work out. I’ll break it down in three basic options.
First is canned air. It looks like an aerosol spray can and that’s what it is. There’s just no paint in there. You screw on a valve to the top of the can, attach the air hose and spray away. The pros are that it lets you start airbrushing on a shoestring, takes up zero space, and is dead quiet. The cons are that while it may be cheap in the beginning, the cans don’t last that long, so it gets expensive in the long run.
In addition, when the propellant in the can is released, it cools the can down. The effect of this is that it causes the air pressure to vary dramatically. You may start with 40 PSI and be down to 10 PSI within a matter of minutes as the can cools. This will change the spray pattern, the finish, and could even cause the paint to stop spraying. Usually, you thin your paint to spray at a specific pressure, so this can be a big problem and is generally a deal breaker. However, if you are only using an airbrush once in a blue moon, and don’t need much control over you spray pattern, it may be an option.
Compressed Air Tank
The next option is a compressed air tank. Get a large tank, attach an air regulator and hose, and spray. The larger the tank, the longer it will last, obviously. The easiest way would just be a standard air tank, which you could fill up at the gas station. You can go a bit farther and rent a welding or SCUBA style tank with CO2 in it. The pros of going this route are for one, silence. You’ll only hear the hiss of air coming out of the brush. Also, if you use CO2, the gas is completely dry. No need to worry about any moisture building up in the air line.
A big plus is that you can regulate the pressure. You will be able to spray with a steady, smooth, consistent pressure the whole time you work. It will also last quite a long time; years even, if you get a big enough tank. This does lead to the cons though. Eventually, you will have to lug it somewhere to get it filled, hopefully not in the middle of a project. If you do go the CO2 route, beverage or paintball supply places will be able to refill the tank. I’m told the cost is usually around 30 dollars. Additionally, some welding or SCUBA companies may rent you the tank and just trade for a full one when you empty it.
Ensure that you are using an inert gas for airbrushing though. CO2, Nitrogen, or compressed air is fine, but certainly stay away from oxygen, hydrogen, helium or anything like that. Aside from not wanting to breathe some of that in, you could end up with a nasty explosion. Space could be an issue here as well. The tanks can be fairly large and heavy, so you’ll need to work out where you are going to put it if this way interests you. Remembering of course at some point you’re going to have to move it somewhere to get filled, so think of stairs, accessibility, etc. The final con is that there is a possibility of the tank rupturing. While the chances of this are pretty damn slim, if it does happen, it could mean a 100+ pound missile sailing through your house.
The third option, and perhaps the most obvious, is a compressor. In general, the compressor allows you to have a steady pressure that is always available. No need to go fill it up somewhere, no wonky pressures, and can be space efficient. Sounds great right? Well, this topic alone generates a lot of controversy and options, so I’ll break this section down into yet again three options.
Compressor option #1 is a shop compressor such as what you may find in a hardware store. Relatively inexpensive, they move a ton of air, allow you to regulate pressure, and you can use them for more than just airbrushing. However, they are big, heavy, and LOUD. Like REALLY loud. Now, most do have a tank attached, and will only run to fill it up after the pressure drops to some lower limit. Get one with a big enough tank, and it may only run once or twice in a few days (this is even with near constant use). But still, it may not be something you want to have kick on in the middle of some delicate detail work, or taking up half your modeling room. Now, there are a few ways around the noise thing. First is to move it far away from where you are working, and run a long air hose to your workbench. Second, is to build a box around it to attempt to muffle the noise. Be careful not to overdo this or you could starve the compressor of airflow and cause it to overheat pretty quickly. Finally, you could buy a small air tank and operate off of in your modeling room, and then use the shop compressor in the garage to periodically fill it up. So, if you have a lot of space, don’t mind the noise, or have a good way to muffle it, this can be a pretty good way to go. If any of that is a problem, you may be more suited to a hobby compressor.
Hobby compressors are most likely the most common choice of anything mentioned here. For the definition of “hobby compressor” I’m going to use this to describe compressors made specifically for airbrushes. The cheapest and simplest of these are the small desktop models such as the Iwata Sprint / Smart Jets or the Paasche D500. These are usually oiless compressors with a max pressure output of around 40 PSI, which is perfectly adequate for modeling. The pros are that they aren’t all TOO expensive ($100 – $500, depending on the options) ; they are always ready when you need it, and are pretty quiet. The noise is a dull rattle – you can usually hear the TV or music over it. It certainly won’t wake the neighbors like a shop compressor. The cons to these types are mainly pressure regulation and heat. For the most part, a bleeder valve is used to provide some degree of regulation, but it is not ideal. Also, most of these run constantly to provide pressure, which causes them to get hot during extended use. If you airbrush a lot, you may burn one up in a relatively short amount of time. For the most part, buying a more expensive model mitigates these problems.
Going up the product lines, we see models that have a tank to keep the compressor from constantly running, or an honest to goodness air regulator instead of a bleeder valve. Some models have an auto shutoff valve in them so that the compressor only runs when you push down for air. Keep in mind though, that for the most part, the compressor motors themselves is exactly the same, the price increases to add some of these features. For example, the Iwata Smart Jet Pro is the exact same compressor as the Sprint Jet, but with an auto shutoff valve, and true air regulator. One “issue” that you may see brought up is the issue with air pulsation on a compressor without a tank. Some claim that without a tank to smooth out the air flow, your spray pattern with look like “0-0-0-0-0-0”. In MY experience, I have never had this issue when using tank less compressors. But, as they say, your mileage may vary. They are pretty friendly as far as space is concerned as well, some can even fit right on top of the workbench. For the most part, these types of compressors are more than adequate for modeling. Manufactures like Iwata (Power Jet / Smart Jet Series), Badger, Paasche, and Sparmax all have a good reputation and will serve you well.
I should highlight here that the I am not including the really cheap hobby compressors in this category. Usually housed in plastic cases, these cheapies generally are totally inadequate. They only put out about 15 PSI and have a reputation for breaking pretty quickly. Also stay away from models that are mainly intended for fingernail painting -these just don’t put out enough pressure.
I suppose the true nirvana of airbrushing is in the silent compressors. It’s really all of the pros with none of the cons, save one. Cost. Out of all the options listed here, this is easily the most expensive, with an average street price a bit north of $1000. They are, as the name implies, almost completely silent. They are based on refrigerator designs, so think of how noisy your fridge is and compare. They move a lot of air too. Most can put out up to 100 PSI and are capable of running multiple airbrushes. They are almost always supplied with a true air regulator and tank, so no need to worry about air pressure or air pulsating. They are also oil compressors, so they tend to last longer then the oiless designs. These compressors are generally a bit bigger than the hobby compressors, but it is pretty manageable. I personally use an Iwata Tiger Shark, and it fits nicely in the kneehole under my workbench. I run the air line through the hole that is made for power cables to come through, and this setup has proven to be pretty space efficient. So quiet, always ready, last forever, great air regulation and lots of it.
On the surface they seem great, and they certainly are, but the cost is a hard pill to swallow. Especially if this isn’t something you are doing professionally. With the hobby compressors being perfectly adequate at a tenth of the price, most people wont go this route but if you have the dough, rock on! In addition, I will say that if you find yourself airbrushing a lot (like a few hours a day) this is probably the way to go. While the initial cost may be high, you will find that not having to deal with filling tanks, overheating compressors, or any noise is worth the extra cost. Not to mention that these are designed for that kind of use, and having something that is built to run and last will be beneficial in the long run. The Iwata Shark series, and the UK made Bambi are great compressors that would serve you well.
On a side note, if you are handy with tools, you can find instructions online to build your own silent compressor using a refrigerator compressor. So if you know what you are doing, a silent compressor could be in reach. Also, look out for online deals as well. I was fortunate enough to find the Tiger Shark on clearance when it was discontinued, and was able to end up with a Silent Compressor at a Hobby Compressor price. Keep your eye on the used market as well. I have seen some pretty good deals on used compressors come up on places like Craig’s List, Ebay, and Airbrush / Modeling Forums. Unfortunately, Iwata has eliminated the cheaper /smaller models in the Shark Line, keeping only the Hammerhead (~$1100) and Great White (~$2000), but I have seen used Mako Shark and Tiger Shark models come up for sale at prices well under retail.
One thing to keep in mind with compressors of all types is moisture in the air line. When you compress air, it heats up, and causes water vapor to form. As the air flows down the line the vapor condenses and you end up with water in your air line. Now, you certainly don’t want this spitting all over your work, so you need a way to get rid of it. This is where moisture traps come in. You need to put some thought in this though, its more than a matter of just throwing one somewhere in the line. Remember, the water condenses as the air cools, and the traps won’t work if the water is still a vapor. So if you put it right at the output for the compressor, the air wont cool enough by the time it gets to the trap and you’ll have water in the line. Install it a few feet down the line, or find a way to cool the air before it hits the trap. Redundancy is also a good thing here. For example, I have my main trap a few feet down the line, and then a small secondary trap screwed right on the airbrush. This will remove any water that managed to squeeze through the main trap, which can happen, especially in a humid place like New Orleans. Finally, remember to keep an eye on them and drain them frequently. A trap full of water is basically useless.
Also, in regards to moisture, if you have a tank attached to your compressor, remember that you will need to periodically drain the air tank. If you don’t, water will start to pool up on te inside and could eventually corrode the inside of the tank and cause it to rupture. The tanks have a stopcock on the underside to drain it, so don’t forget.
This should give you enough to chew on as far as air is concerned, and if you have any questions or need clarification, please feel free to ask in email. Next installment, we’ll get into why you probably started reading this series, the Airbrushes themselves.