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Hopefully this thread will help a few people who are trying to get started airbrushing. First off, if you live in the USA, NPT fittings are everywhere. The chance of finding a BSP fitting at a local hardware store is almost non-existent. In order to connect most airbrush hoses to a regular compressor you will need both an NPT and a BSP fitting. BSP fittings are easily found on e-bay. The two fittings that the majority of users will need are one FEMALE NPT FITTING 1/8 INCH. and one MALE 1/8 INCH PIPE UNION. You will also need some Teflon tape. Because the BSP fitting is slightly smaller than the NPT fitting you can screw the 1/8 BSP MALE into the 1/8 NPT FEMALE. The connection will be loose if you don't wrap it generously with the Teflon tape. I am posting some pictures below to show the small difference. The 1/4 inch NPT FEMALE part that is shown is from a paintball remote line and is only only used as an example of a 1/8 inch NPT FEMALE fitting. I did not use Teflon tape to secure these fittings but it MUST be done to convert the NPT to BSP. Good Luck!

I'm not quite sure I follow what you are doing here. What kind of hose are you trying to connect to what brand of airbrush? Also, wrapping a joint with extra Teflon won't seal the joint if the threads don't match, Teflon tap does is not a sealant.

The pics are simply to show the difference between the sizes of the fittings. Its rather simple really. The female NPT fitting is large enough for the BSP fitting to fit inside with a small amount of play, the threads match, they are just slightly smaller. Adding the Teflon tape is sufficient enough to stop any air leaks as long as you aren't allowing anything higher than 100 PSI meet the seal. There is no adapter that changes NPT to BSP, so you have to do it yourself unless you want to custom order the part from a machine shop. NPT is the standard fitting in the USA so anyone from the UK may not get why I posted this lol

 JohnDoe1990 wrote:
The pics are simply to show the difference between the sizes of the fittings. Its rather simple really. The female NPT fitting is large enough for the BSP fitting to fit inside with a small amount of play, the threads match, they are just slightly smaller. Adding the Teflon tape is sufficient enough to stop any air leaks as long as you aren't allowing anything higher than 100 PSI meet the seal. There is no adapter that changes NPT to BSP, so you have to do it yourself unless you want to custom order the part from a machine shop. NPT is the standard fitting in the USA so anyone from the UK may not get why I posted this lol

Okay, you didn't answer my question. What brand of hose are connecting to what brand of airbrush?

They are just made in china hoses with 1/8 BSP fittings on each end connecting to an Iwata airbrush. What I have done to make my setup work is this.
The compressor has a standard 1/4 inch NPT industrial plug. I replaced it with one that ends in 1/8 NPT female end. I screwed a 1/8 BSP male pipe union into the 1/8 female NPT port after wrapping it generously with Teflon tape. I screwed the first hose which is coiled into the 1/8 BSP fitting, and screwed the other end onto regulator. From the regulator there is a ten foot braided hose with a quick disconnect on the end which connects to the airbrush.


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Compressor - 1/8 inch NPT female plug - 1/8 inch BSP union(has two male ends) - coiled air hose - regulator - braided air hose - quick disconnect - airbrush.

Totally baffled me there :/ why would you use an NPT adapter in a BSP setup?
Airbrush suppliers will likely be selling the adapters you need in BSP.

I had never understood why Badger use that tiny little connection that they do; perhaps it is purely about availability of BSP fittings in USA?

Wiki certainly seems to suggest that USA are the odd ones out,
http://en.wikipedia.org/wiki/British_Standard_Pipe
if you're the only ones in the world not using BSP... its probably time to join the rest of us

The reason for using the NPT fitting is because there is not a BSP fitting that fits into the quick disconnect. Thus is must be converted. The only NPT fitting is the plug that connects to the compressors quick disconnect.

 JohnDoe1990 wrote:
The reason for using the NPT fitting is because there is not a BSP fitting that fits into the quick disconnect. Thus is must be converted. The only NPT fitting is the plug that connects to the compressors quick disconnect.

Okay, I follow you on that. I have two compressors and 6 airbrushes of various manufacturers and I have never had to use BSP fittings to connect any of them. For instance, here is an airbrush hose for an Iwata airbrush.

I'm confused by your set up as well, why is your regulator midstream and not directly after your compressor (usually screwed directly into the discharge on the compressor)? Also, what brand of air compressor do you have that has an 1/8" discharge?

 ScootyPuffJunior wrote:

 JohnDoe1990 wrote:
The reason for using the NPT fitting is because there is not a BSP fitting that fits into the quick disconnect. Thus is must be converted. The only NPT fitting is the plug that connects to the compressors quick disconnect.

Okay, I follow you on that. I have two compressors and 6 airbrushes of various manufacturers and I have never had to use BSP fittings to connect any of them. For instance, here is an airbrush hose for an Iwata airbrush.

I'm confused by your set up as well, why is your regulator midstream and not directly after your compressor (usually screwed directly into the discharge on the compressor)? Also, what brand of air compressor do you have that has an 1/8" discharge?

This is the compressor ( http://www.homedepot.com/p/HDX-3-Gal-2-Amp-Pancake-Air-Compressor-with-13-Piece-Accessory-Kit-0210384/204339561?N=5yc1vZc27p )

The standard fittings are 1/4 NPT. I use a plug that is 1/4 NPT x 1/8 NPT female, then I wrap a 1/8 BSP union with Teflon tape and screw it into the 1/8 NPT female end on the plug. Then I connect my air hose to the BSP union, its an exact match. The compressor has a built in regulator so the coiled hose is just there to condense any moisture before it meets the second regulator which has the water trap. Then the straight hose provides dry air to the brush. Its confusing to read but if I could show you the parts in action you would just say OH!

I will be upgrading to this compressor soon http://www.homedepot.com/p/California-Air-Tools-6-3-Gal-1-HP-Ultra-Quiet-and-Oil-Free-Steel-Tank-Air-Compressor-6310/202977399

Okay, you are still doing a lot of unnecessary steps to get air to your airbrush. You don't need two regulators, one is plenty. All you need is that hose I linked (it is 1/4" x 1/8" and cost $8) and to take the quick connect chuck off the discharge of the compressor.

Actually, two regulators are not a bad idea with that compressor. High pressure regulators are usually accurate +/- 5-10 PSI. This is fine when regulating framing nailers and other pneumatic tools. To dial it down to the range which is useful for airbrushing though, you want a more precise regulator/gauge set.

You have one regulator on your compressor and then a second near your brush. The one on your compressor is dialed down to something like 50 psi. Then you can adjust the pressure at your workstation with a micrometer regulator without fear of blowing out the regulator.

For me, it has the added benefit in that my compressor is located outside of the house. I have the incoming air regulated to 65 psi. It then goes through the attic to my hobby room. My airbrush station has a manifold with four seperate regulators mounted before quick connects. For some techniques, I will usea couple different brushes with different paints in rapid succession. Each needs its own pressure setting, so that allows me to avoid resetting the pressure each time.

While you can avoid the extra plumbing, it really isnt a problem after you have everything setup. It also has benefits over a single valve setup, especially if you are using something other than an airbrush compressor.


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Also, the coil before seperator is a long held technique to help improve the efficiency of moisture traps. Lets the air cool some before the trap. Since alot of traps are combo seperator/regulators - it doesnt hurt things.