6063 aluminum is the most popular alloy for extrusion and so it is a natural consideration. This alloy is widely used in architectural applications. Because of this, it is often referred to as architectural aluminum. It is a medium strength alloy, which is used for applications such as railing, window frames, door frames, roofs, balustrading, sign frames, shop fittings, irrigation tubing, building products, electrical, marine, piping, recreation equipment, storage tanks, truck frames & trailers.