The disclosed apparatus, systems and methods relate to the design principles for forming a welded joint between two sections of tubing or pipe. The material at the end portion of a first section of tubing to is folded inwardly to create a support surface. This support surface improves the ability to weld light gage material with traditional arc welding and it creates conditions to allow brazing to be as strong as traditional arc welding by using A shaped piece of filler material which is located at the intersection between the support surface of the first section of tubing and a side wall section of the second section of tubing. While holding together the first and second sections of tubing with the filler material, heat is applied at the intersection at a temperature and for a duration sufficient to melt the filler material and form the 3t joint.