Construction of durable and watertight soldered sheet metal joints is difficult to achieve in a field environment where dust, dirt, debris and other contaminants can limit the effectiveness and quality of the soldered joint. Although proper material and equipment selection is crucial in preparation for soldering architectural sheet metal, detailed forming, cleaning and soldering techniques are also necessary to ensure durable and watertight soldered joints.
Base Metal Forming
Proper forming techniques begin with cutting and folding of the base metals. If the sheet metal components do not have straight and crisp cuts and folds, the joints between the sections of metal cannot be “dressed” tight to one another, which may inhibit flow of the solder into the joint. Where feasible, perform the majority of any sheet metal cutting and forming operation on a shear and bending brake, respectively. Limit hand shaping, trimming and seaming in the field as much as practicable and ensure that any field work is performed with proper sheet metal hand tools. Form flat lock seams with 1/2 to 3/4-inch legs on the seams. Initially, leave bends in base material under-bent (partially open) to permit proper cleaning and pretinning of joint interior surfaces. Pre-drill any joints to be riveted prior to cleaning the sheet metal to avoid metal shavings remaining within the joint that could inhibit uniform solder flow. Read More.