Aluminum vs Stainless Steel: Which is Better?

Metal signs speak volumes. Their sturdiness, malleability, and sleek finish add a level of finesse to business signs. Making the best decisions about the design of your business’ sign shouldn’t be your sole consideration. The type of metal used also plays a major role in how long it will last in external weather conditions. Aluminum and steel are two of the best metals to use in metal signs. The table below compares both types of metals so that you can make an informed decision about the best metal to use for your sign.


Aluminum vs Stainless Steel

Strength to weight ratio

(Force per unit area divided by density)

Aluminum has a tensile strength of 276 MPa and a density of 2.81gcm-3. Aluminum is, therefore, lighter than steel.

Stainless steel has a tensile strength of 505 MPa and a density of 8 gcm-3. Stainless steel is, therefore, stronger than aluminum.


Aluminum creates a passivation layer that helps it resist oxidation and corrosion. Aluminum comes in multiple different alloys with the bulk of all aluminum being 5052 and 6061. 5052 is considered marine grade and is more resistant to corrosion than 6061.

Stainless steel contains chromium which has corrosion resistance properties. Stainless also comes in different alloy, with the bulk of all stainless being 304 and 316. 304 is the most common type of stainless steel. 316 has a greater resistance to corrosion. 316 costs costs more than 304, but it will last longer.


Aluminum is more expensive than stainless steel, when you compare it by weight. However, aluminum is about 1/3rd the weight of stainless steel, and when you compare the cost of the same volume of material, stainless steel is much more expensive, usually by about 30%


5052 aluminum is very malleable. 6061 is likely to crack if bent. Aluminum is weaker than stainless steel and therefore is more likely to bend.

Stainless steel is more likely to keep it’s shape than aluminum,

Electrical Conductivity

Aluminum conducts electricity well.

Steel is one of the poorest conductors of electricity amongst all the metals.


Aluminum is more difficult to weld than steel. When choosing an aluminum to weld, choose 5052, it is easier to weld than 6061.

Steel is less difficult to weld than aluminum.

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What does this mean for you?

Aluminum is a better metal to use for outdoor signs because it has better weather resistance than steel. Steel, however, has superior strength. So, if you’re comfortable with rust developing on your sign overtime in favor of something stronger, steel is your best option. Both metals can be used for indoor signs.

Essentially, the choice you make depends on what you’re willing to live with. Both metals will give you the refined look you desire. Their strength and weather resistance are the ultimate decision factors.


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