Sizing and Terminology
For reference, and when you're looking for anything to connect to the line, compressors use attachments called NPT or National Pipe Thread. (North American) In other parts of the world, this rating may be different, for example, the BSP or British Standard Pipe thread.
The size that air compressors use is quarter inch.
So, what you're looking for is 1/4" NPT.
- Water / Dust Trap
Cleaning the filter is a simple matter of unscrewing the bottom to let out water and dust, and replacing the internal filter as required.
It's recommended to place a trap as near your tool as possible - however as I explained with airbrush traps, I don't want the extra weight while I'm painting, so I place it right after the compressor instead.
- Quick Release Valve
It’s just two parts designed to click together. Yes, they're called "Female" and "Male" adapters. Can you guess which is which?
- Manifold (aka, a splitter)
Keep in mind that if your tank is only providing 35psi, two airbrushes (or other tools) at once means your pressure gets split between two devices and won’t be enough to run either one of them; while turning the air up to 70psi would damage both of them. The solution is to use a regulator. (see below)
Splitters are available to split from one to two or three or four or more... or you can connect multiple splitters together.
For example, if you have a compressor / tank in your garage then you might want to use it in both the garage and your hobby room. (one at a time only) Therefore, you put a splitter on the output, have a small tube in the garage and a long tube run to your hobby room with a closed valve on the end of each tube. To work at one place, open it’s valve up.
If you use any kind of valve to adjust pressure (by closing it half-way for example) the pressure on the line doesn't change - it would be like using a smaller tube.
A Regulator (explained below) is different, in that instead of being ON or OFF, it can adjust the actual pressure on the line.
- Automatic Release Valve
A Regulator (explained below) is the usual thing we would use to control pressure passing through a line for our uses.
- In the first photo, it shows that if the valve isn't set, it lets all the air through.
- In the middle photo, the valve is set to 15 psi, meaning you want to ensure that no matter what the pressure on the line is, only 15 psi gets through and the rest is released into the air.
- In the last photo, the valve is set to 25 psi. The line pressure is 30 psi, so the extra 5 psi is released to the air.
These valves don’t solve everything as some might only be able to release so much pressure at once.
In the above example, say the auto release valve is set to 25 psi, but the line is at 50 psi instead of 30. That’s 25 psi too much and the valve will start venting to the air – HOWEVER, your automatic release valve might only be able to release a max of 5 psi. This means you’ll still have an extra 20 psi on the line.
To continue with the above example, you’re in the hobby room and have no idea what the pressure on the line is – unbeknownst to you, it’s at 70psi and could damage your airbrush. If you place a splitter on the line in your hobby room, you can attach a gauge to one of the outputs. This way, you can at least see what the pressure is on the line and know that you’ll have to run to the garage and turn down the pressure.
- Regulator (Gauge w/ Pressure Controlled Valve)
Make sure your regulators can handle that much pressure. Shouldn’t be a problem for most, but hobby grade ones might have lower pressure maximums. Also, regulators can be expensive...
If you start splitting or extending the line, you may want control over the pressure where you’re working or to allow multiple people to work at once. (As a bonus, each person can work with different pressures.) The main pressure will have to be set high enough that it can supply both regulators at the same time.
Once again, you’ve got a compressor / tank in the garage and a splitter to supply air to both the garage and your hobby room. Instead of a valve on both ends, you could use a regulator. That means that in the garage, a regulator could be set to 70psi for tools and 35psi for your airbrush in your hobby room. The main compressor would need to be set to at least 105psi (preferably higher) to supply enough pressure to the line that both tools can be used at once. You won’t damage your tools/airbrush because the regulators will only allow so much pressure through.
Another example would be this: Maybe you don’t want to split the line at all, but you do want to keep the compressor in your garage to avoid the noise. This just means running a long line from the garage to your hobby room, so technically you don’t need a regulator… but the last thing you want to do is run to the garage every time you want to adjust the pressure. Instead, set the compressor to the max pressure your airbrush can handle and add a regulator in your hobby room.
The next post is going to look at practical examples of how to use some of these in-line devices.
Take a look at the Wargaming Tradecraft Techniques Page for links to the entire Airbrushing series and other tips, tutorials and information.