High Density Polyethylene, or HDPE, pipe is a heavy-duty style piping used in physically demanding environments to transport things from water to natural gas on landfills. HDPE pipe is extremely durable, and relatively expensive compared to other pipe, such as PVC. HDPE pipe is generally used underground and with a high rate of flow of whatever is being transported. It would not typically be used in a small scale system, like a home or a school or other general building. Because of its value, it is very important to weld pipe together properly to get the most value out of a length of pipe. This guide will explain how to most efficiently weld HDPE pipe and get the most out of an investment and to have sturdy, solid fuses in the field.