Welding fluoropolymer pipe and fittings

In the art of joining together the ends of tubular flow ducts of fluorine based materials including fluoropolymers, and including fluorocarbon resins identified as fluoroethylenepolymer and perfluoroalkoxy, which are highly chemically inert and have continuous service temperatures in the range of 300.degree. to 500.degree. F., the method steps consisting of

• shaping the end faces of the ducts to lie flat and normal to the duct axis,
• arranging an electrically heated flat faced infrared heater with a temperature of 1250.degree. to 1700.degree. F. and with the glowing faces in confronting and closely spaced relation with the aligned ends and spaced from such ends up to about one-half inch, maintaining the heater between the duct ends for up to forty-five seconds and until the end portions of the duct become visibly molten to depths of up to one-eigth of an inch from the end faces of the ducts,
• removing the heater from the duct ends, and
• immediately moving one of the duct ends into engagement with the other duct end, and with only a minimum of pressure pressing and holding the duct ends together until the molten portion of the duct solidify again.