How to reinforce aluminum sections or profiles?

Aluminum is a soft material not well suited for bearing any significant loads. There are several means to overcome this limitation:

  1. Increase the wall thickness of the profile.
  2. Change the cross-section of the profile to increase the Modulus of Elasticity (i.e., the "stiffness") of the design. Design a hollow section, I-Beam shaped profile, a Lap profile etc.
  3. Insert additional supporting elements inside, outside, or next-to the aluminum profile in question.

It is here disclosed that a specific material is rather well suited for reinforcing an aluminum profile in light structures. The patents and patent applications below specify only "steel" in general or other material as reinforcing agents - not hardened steel. Though steel is a strong material it is a heavy material as well. Combining aluminum with steel removes quickly the weight advanrage of aluminum extrusion.

However, there is a breed of steel products which possess extremely high strength combined with relatively low weight. These materials are martensitic steels or more commonly referred to as "hardened steels". As these are readily available it will be just a matter of combining a piece of hardened steel to a profile designed to accept such a reinforcement.

Well suited to use with aluminum are AISI 400 Series Stainless Steel grades. They include AISI 410, AISI 420, AISI 430, AISI 440 and many other hardened stainless steels. There exists a wide variety of these products under hundreds of brand names and in various sizes.

Mind you, it may not be as simple as this.

My reply: There are several cases where this solution makes economical sense. Just forget the inherent beauty and calculate the costs.


With these caveats in mind, feel free to apply this method in your designs. There is no patent preventing the use of this method or combination of materials. Now that I have published this there will be no patent. Granting a patent requires novelty: Unpublished and/or not used anywhere before. If this information exists in internet - you bet it is published! Think of this as the principles of Open Source applied to metalworking.

This information is published on the day the domain was registered. January 8 2008.


Some related patents and patents applications:

These may contain examples of how to apply the information given above. Some of them have expired.


Why? Is this not too obvious? Too simple for a patent?

It is and it may be. But the thing is I need to use this method. And it is too hard to predict when a patent will be granted and when not.

I give an example. You can buy the material in the following patent from almost any hardware store. It is a standard shape. And then a patent excludes you from using it. Who would have guessed the application would succeed. - I am not taking my chances. Originally a Swedish patent, Published as Publication number: WO02070833

"This is close: You take a piece of common plumbing and apply for a patent. Surprise, surprise - you will be granted one."