Abstract: A heater box to bend PVC conduit in the form of an elongated metal box, split into upper and lower portions and hinged along one side so as to be openable for insertion of a segment of a plastic conduit lengthwise through the box, the box having, at either end, cutout portions so as to allow the closure of the box around the pipe. In one embodiment, corresponding semicircles are cut from upper and lower end portions of the heating box so as to allow a pipe segment to fit when placed therein. A burner located within the lower box portion extends along the elongated box to provide uniform heating. A baffle extends over the burner along its length. The box bottom and lower sides are perforated to provide combustion air. The hot combustion gases are directed upward around the baffle and up to the conduit segment. Supports, spaced along the length of the elongated box support the heating pipe segment above the hot baffle. These supports run perpendicularly underneath the plastic pipe while heating.