Patent ID: 7935211

Claim:
A method of welding a window frame or sash comprising: providing a welding system having movable head fixtures, certain of the head fixtures including cutting structure and each head fixture including heat supplying structure, providing a one-piece lineal having first and second ends and notches therein, loading the lineal with respect to the head fixtures, with portions of the lineal being folded about the notches to define folded corners, one of the certain head fixtures being associated with each folded corner, moving at least some of the head fixtures to clamp on the lineal, employing the cutting structure of the certain head fixtures to cut the lineal generally at each notch to separate each of the folded corners from the lineal, with each corner of the lineal being defined by a pair of ends, repositioning the head fixtures so as to provide a space between each pair of ends, aligning each pair of ends, inserting one of the heat supplying structures into each space to transfer thermal energy to each pair of ends, removing the heat supplying structures, and moving the head fixtures so that each pair of ends contact and join in a thermally welded manner.