When metal roofing manufacturers first introduced aluminum material for roofing, much of the aluminum produced was 0.8mm thick.
However, over the years, the building products industry has been gravitating to thicker roofing and trim materials, especially aluminum.
Consequently, contractors were transitioning from the use of 0.4mm to 0.6mm thick Galvalume or Hot Dipped Galvanized steel roofing and trim products to 0.8mm to 1.2mm thick Aluminum. Many contractors assumed aluminum bent the same as steel and thought minor adjustment was needed to make crisp bends on aluminum as they had done with steel. This resulted in some contractors bending these heavier aluminum products beyond their tensile strength limits resulting in cracking of the metal and paint and leaving a silver look from the crazed aluminum under the paint.
Contractors can keep the aluminum alloy from cracking under the bending strain by properly adjusting the sheet metal bending brake. To set up the hand brake to perform the bend, recess the top clamping leaf of the hand brake.
This will reduce the amount of strain applied to the aluminum and allow you to get a proper bend on the aluminum alloy sheet.
