Why are some 4'X4' Systems manufactured from steel rather than aluminum?

The reason is the basic cost of steel is less than aluminum. Manufacturing and installation is faster with aluminum because of its lesser weight. However, aluminum is 1/3 the weight of steel and shipping costs are less.

Example: A 6' Module Steel Beam is about 97 lb.., vs. an aluminum unit of about 35 lb.. A 97 lb.. Beam requires two work men to handle etc. Any modification for tool fit up becomes very difficult and slow with the steel, when compared to the modification of aluminum understructure. More.

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