Galvanizing has been used to protect iron and steel from rusting for well over one hundred years, in places as diverse as the wire rope used for the suspension cables on the Brooklyn Bridge to gutters on houses. Galvanizing, which is simply coating steel with zinc, protects steel from rusting by forming a protective barrier between the steel and the environment, like paint does BUT galvanizing goes one giant step further than paint, it provides electrochemical protection of the steel in addition to forming a protective barrier. Since zinc is more reactive than steel,  it oxidizes to protect the steel near it, as a result, even if a galvanized steel surface is scratched down to the bare steel, the galvanizing will prevent the steel from rusting. Galvanized steel, therefore, is a superior product to steel with any other type of coating.  The galvanized steel framing in your new Hawk trailer is additionally primed and painted, unpainted galvanized steel has a rust free life expectancy 5 to 10 times longer than non galvanized steel.  

Galvanized VS Aluminum Frame

The density of aluminum is approximately one third of the density of steel; as a result, structures made of aluminum have the potential to be lighter weight than the same structure made from steel; however, aluminum is not as strong or stiff as steel, and when these factors are considered, the potential weight savings of aluminum over steel is reduced. 

Since the elastic modulus of aluminum is one third the modulus of steel, a structure built from aluminum will deflect more than the same structure built from steel. This can be significant when the structure is subjected to wind loads which may cause movement of the structure which will result in fatigue loading. To compensate for deflection, one either has to increase the size of the members or add additional stiffeners or braces, this increases the weight of the members or adds additional members. 

The life of your trailer is dependent on its ability to withstand fatigue stress as you drive down the road. Galvanized steel has a fatigue strength about 30% higher than aluminum. 

When welded, heat treatable aluminum alloys ( 6000 series ) lose a significant portion of their strength. For example, 6061-T6's tensile strength drops from 42000 to 24000 psi, the is about a 50% reduction in strength and is so significant that it is necessary to locate welds in low stress areas in the design made from aluminum. This often requires the use of thicker tube sections or the addition of extra bracing. 

When welding the galvanized frame on your new Hawk trailer, the loss of strength is of minimum concern for example 48000 to 45000 psi for standard materials. Hawk Trailers uses Allied's Gatorshield galvanized steel for framing, all welds are treated with a cold galvanizing compound for rust resistance. This process provides a rust free life expectancy of 15 to 30 years under normal conditions even when NOT additionally coated with paint, primer or powder coating as in a Hawk Trailer.  

Aluminum does not rust like untreated steel does, however, it does corrode, pit and develop a loose white powdery surface, aluminum corrodes particularly quickly when exposed to urine and manure. 

What about galvanic corrosion? ( sometimes incorrectly referred to as electrolysis) The exterior aluminum on your new Hawk trailer is poly coated UV protected on both sides, additionally, the galvanized frame is fully primed so the aluminum and steel are not in direct contact. Further, double coated acrylic foam tape is used between the metals to prevent their contact and protect from corrosion.