When selecting fittings for your compressed air system, people ponder whether they should get steel or brass air fittings. This article will provide you on all the relevant information on both, and set out the differences!

Table of Contents

What are Air Fittings?

Pneumatic fittings provide an ever so essential link between tubes, hoses and other components in pneumatic systems. Air fittings typically have tighter seals and lower pressure requirements compared to hydraulic fittings and are available in various connector types.

Not only do air fittings connect pneumatic components and stop the flow of unused ports, but they can also be used to control directional flow and air flow pressure. These fittings are available in different styles such as:

  • thread to barb fittings
  • threaded fittings
  • barb to barb fittings
  • push-in fittings
  • metric fittings

What are Steel Air Fittings?

Steel, or stainless steel, fittings are designed to be used with high pressures, vacuums and consistent vibration in order to deliver leak-proof joints. This makes steel fittings suitable to almost any environment, particularly pneumatic and hydraulic applications.

Due to their great strength and corrosion-resistant properties, steel fittings are well-suited to water hammer and vibration applications, whilst delivering excellent sealing and retention of the pipes.

Here’s an example of a 9 piece air compressor hose fitting set made from steel.

What are Brass Air Fittings?

Brass fittings are suitable for a range of applications within pneumatics and medium-pressure hydraulics. They are particularly compatible with various industrial fluids and boast great corrosion-resistance.

Brass is a copper alloy made with Zinc, and the addition of Zinc allows the corrosion resistance, strength and hardness to be greater. Brass fittings are also resistant to high pressures due to their high tensile strength.

Here’s an example of a 30 piece Brass air fittings set readily available on Amazon.

Steel vs Brass Air Fittings – Which is Better?

Both steel and brass air fittings have their own benefits. A major benefit that brass fittings hold over steel fittings is that they boast significantly great corrosion-resistance. In addition to this, in terms of thermal and electrical conductivity, brass outweighs stainless steel by up to 15 times.

Brass fittings are perfect for applications which involve extremely high temperatures as they have a significantly higher thermal expansion coefficient. Stainless steel is more suitable for applications that require fluid control of petroleum and high acidic liquids.

Therefore, in terms of pneumatic applications, brass are the better fittings. However, it is important that you use steel fittings for steel piping as brass fittings are not recommended on steel tubing. Brass is softer than steel and may not seal onto the tubing as well as steel fittings, and so, this may result in air leaks.

It’s possible galvanic corrosion will occur, which is a process where the corrosion is accelerated by 2 dissimilar metals in contact with one another. If you have copper tubing, then this is the ideal time to use brass fittings.

Brass as a material, is typically more expensive than steel. But, it is likely that your brass fittings will seal a lot better than steel

It’s possible to purchase kits which combine brass and steel fittings like the one below on Amazon!

This youtube video below provided by Gregg Distributors LP is a great ultimate guide, covering all aspects of fittings including the materials.

FAQs (Frequently Asked Questions)

Can you mix brass and steel air fittings?

Yes, a lot of people tend to use both types of air fittings in their compressed air systems. But only certain types of stainless steel and brass can be used together. If the wrong types are used together, the system will experience galvanic corrosion. And so, you should try to use steel fittings with steel piping and brass fittings with copper piping only, to avoid this risk.

Can you use brass fittings for air?

Yes, brass fittings are extremely suitable for compressed air systems as they boast great corrosion-resistance and are also resistant to high pressures due to their high tensile strength. It is advised that brass fittings only be used on copper piping and not steel piping, as the coming together of steel and brass may accelerate corrosion.

Useful Reading

If you have any questions regarding steel vs brass air fittings, please leave a comment below, with a photo if applicable, so that someone can help you!