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Aluminum versus cast iron – Which piston compressor material is best?

Thanks in large part due to their versatility and low cost, piston compressors are among the most common air compressors being used today. They are the right choice for a wide range of applications, from DIY to workshops to dentists.

Once you have concluded that a piston compressor also meets your needs best, there is one more decision to make: aluminum versus cast iron.

If you have used our guide on what type of air compressor to choose, then you will know that the first step in selecting the right material for your compressor (which in this case means the pump, cylinders, flywheel and valves) is to figure out how you want to use your new compressor.

When you know, the choice may be easier than you think – even for a layperson. 

Aluminum versus cast iron – lightweight versus heavy duty

To anybody familiar with metals, the main difference between the two is obvious: Aluminum is much lighter. Despite its low weight, aluminium is very strong. It features superior malleability and excellent corrosion resistance, is easy to machine, not susceptible to rust formation, and has good electrical and thermal conductivity. The latter is particularly important for piston compressors because it results in good heat dissipation. In addition, aluminium will heat up enough to vaporize any condensate in the oil. Aluminium’s low density makes it the logical material to use for lightweight compressors that are easier to transport, install, and move around.

Cast iron, on the other hand, is able to withstand high loads. It is a perfect shock absorber. While cast iron is sometimes viewed as problematic because it gives off dust that may be harmful to humans, this is not a problem with Atlas Copco compressors. Among the advantages of cast iron compressors is also that they have long service intervals and feature a high cooling performance. Because it is very durable and much heavier than aluminium, cast iron is the perfect material for compressors that need to operate in heavy duty environments and extreme conditions. One drawback is that cast iron is not very flexible.

Aluminum versus cast iron – your needs decide

Because both materials have distinct advantages, it’s impossible to say which one is better. Ultimately, you have to decide which one is better for you.

However, here is a rule of thumb: If you need a small, flexible compressor, especially for non-stationary use, then aluminium is often the material of choice.

But if durability is most important to you and/or your compressor has to function reliably in tough conditions, then you will probably prefer a cast iron model.

One final note, which is less important for Atlas Copco compressors because of their outstanding durability but should be mentioned in a world in which sustainability is increasingly important: Of the two materials, aluminium is much easier to recycle.

Ask an us about the best options for your needs.

Do you have an idea for our #expertcorner? Let us know!

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Who we are and how Ash Air can help your business!

Ash Air has been around in New Zealand since 1979, and we’ve grown into a nationwide company with international support and a reputation for quality and reliability.We look after all things compressed air for your business!

  • Reciprocating, Screw, air compressors
  • Vacuum pumps
  • Nitrogen
  • An extensive line of air treatment components

Ash Air's range of Chicago Pneumatic, Alup, Pneumatech, and Quincy compressors are used extensively around the world in industries ranging from oil and gas to food, automotive and farming, and we bring you these world class compressors here in the land of the long white cloud.Our technicians are compressed air equipment experts and are dedicated to addressing customer needs. Supported by a 13 locations nationwide, Ash Air offers one of the widest selections of compressed air equipment and parts available today in New Zealand.

Reliability and Efficiency

With Ash Air compressors, you can count on reliability and high performance for even the most demanding applications. We focus our efforts on the following:

  • Increasing uptime
  • Reducing unexpected repairs
  • Reducing energy consumption
  • Improving the cleanliness of compressed air


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