A method of coupling a first pipe and a second pipe with a coupler, wherein the first pipe and the second pipe are made from a reinforced thermosetting resin (RTR) and each have a tapered, spigot end, wherein the coupler has two tapered socket ends adapted to internally receive the respective tapered, spigot ends of the first pipe and the second pipe, the coupler comprising a resistive element implanted therein and connected to electrodes extending to an exterior of the coupler, wherein a portion of the resistive element is exposed to contact fluids transported within the first pipe and the second pipe, the method comprising:
- coating the tapered, spigot ends of the first and second pipe, and the tapered socket ends of the coupler with a tie layer comprising at least a thermoplastic material, such that the resistive element is implanted adjacent to the tie layer of the coupler,
- inserting the first pipe and the second pipe into the coupler;
- and
- applying of electricity to the electrodes such that the resistive elements heat sufficiently to melt the thermoplastic material such that, when the heat is removed, the hardened thermoplastic material seals the first pipe and the second pipe to the coupler.