How to Determine the Difference Between Magnesium and Aluminum


What you will learn in this episode:
Since we released the episode on How to Weld Magnesium we have had the same question come up over and over in comments and emails, "How can you tell the difference between Magnesium and Aluminum?" In this episode of TIG Time we address that question. You will learn two cheap and easy ways to tell whether you have Aluminum or Magnesium. We will also 'debunk' a common myth that you can tell by using a magnet.

Using Vinegar to Determine your Material:
One way to determine whether you have magnesium or Aluminum is by simply pouring some vinegar on the material. When you pour vinegar on Magnesium you will notice that almost instantly it will start to react. You will notice a bubbling or fizzing reaction that will tell you that you indeed do have a piece of Magnesium.

On the other hand, if you try the same test with Aluminum, you will notice that nothing happens. When the vinegar comes in contact with an Aluminum part, it will just sit there, in this case telling you that you do not have to worry about working with Magnesium.

Using the "Shave and Burn" Test:
Magnesium is pyroforic. What this means is that it will catch fire when an open flame is introduced. One of the best ways to tell whether a part is in fact Magnesium, is to shave off some of the material with a knife or file and see if it will catch fire. If it catches fire, congratulations... You've got Magnesium. Aluminum is not pyroforic. So when performing the same test, it will not light up.

Using a Magnet:
We're not quite sure where this one came from, but a common misconception is that you can tell the difference between Magnesium and Aluminum by touching each to a magnet. Neither material is ferrous, so you will actually get the same result for both Magnesium and Aluminum.