Divine Metal & Alloy Aluminium alloy 3105 is essentially a 98% aluminium alloy with minor additions to increase strength over that of alloy 1100 and 3003. It is not hardenable by heat treatment and it has good corrosion resistance, formability and weldability. Typical applications include general sheet metal work requiring greater strength than is provided by 1000 series aluminium alloys, residential siding, mobile homes and sign making.