Transitions are used to connect two pipes of different diameters and are truncated cone whose upper base parallel to the lower base. Each base is a circle. The transition is made from sheet material (steel, plastic) welding. For making the transition is necessary to make the proper marking of the sheet material, t. E. To build a sheeting unfolding transition, then scan cut and weld to form a transition. When cutting should give allowance for processing edges. Daylight is connected with pipes to the weld. Thus, marking the transition to the construction reduces its scan in a sheeting.