Aluminum 3105 is a non-heat treatable alloy containing around 98% aluminum with minor additions of manganese, silicon, iron, copper, and magnesium. This alloy exhibits excellent formability, corrosion resistance, and weldability, making it suitable for applications requiring moderate strength like vehicle bodies, gutters, architectural extrusions, and general sheet metal work. 3105 aluminum is stronger than pure 1100 aluminum but more formable than heat-treated alloys, finding use in residential siding, sign making, bottle caps, and armor.