There are many factors to consider when purchasing magnets for your business. You must consider the size, shape, pole strength, magnetization direction, etc. One important factor that is often overlooked is the air gap.  What exactly is the “air gap?”

What’s An Air Gap?

Say you have a neodymium bar magnet and a magnetic iron bar—When you bring them together, they will attract with their full strength. They are secure and may require some force to pull apart. Now, say you place a non-magnetic material, such as plastic or wood, between the bar magnet and the iron bar. You’ll notice that the magnet and steel may still attract each other, but it feels less secure and requires less strength to separate them. The piece of non-magnetic material between them acts as a barrier, also known as an air gap. The term “air gap” tends to be a little misleading because there’s no air between the two magnetic materials; it is a non-magnetic material placed within the magnetic field and decreases the pull force. Think of it as the space between the magnet and the magnetic material.  Additionally, coated magnets, such as plastic or epoxy, naturally contribute to the air gap. They create some space between the magnet and magnetic material; however, the air gap is not as large as placing, say, a wooden block between them. The general rule of thumb is the greater the air gap, the greater the loss of strength. 

How Does An Air Gap Impact Which Magnet You Purchase? 

Often, magnets for business applications require a stronger pull force and must be able to operate in specific environments and temperatures. Keeping this in mind, when an air gap is introduced, it adds to the equation. Therefore, if there’s a large air gap, you will need to purchase a stronger magnet than if there were none. For example, the pull force required to attach a magnetic hook to a typical wooden wall (with a magnet or metal behind it) is higher than the pull force needed to attach it directly to a magnetic wall.

Apex Magnets Can Help!

If you need help determining the magnetic strength needed, whether there’s a large air gap or you need a coated magnet, don’t hesitate to contact us. Our magnet experts are readily available to assist you. We sell a variety of magnets, but if you need something more specific to fit your business needs, we also offer custom magnets, which are particularly useful when considering the air gap.