An induction heatable corner key, including a generally L-shaped body having an electrically conductive portion and an electrically non-conductive portion wherein the electrically conductive portion is formed of a material that is subject to inductive heating and of sufficient mass to transfer heat to the electrically non-conductive portion and to render the non-conductive portion at least partially molten. And, A method of joining polymer parts, including preassembling at least a first polymer frame part and a second polymer frame part with an induction heatable corner key coupling the first polymer part to the second polymer part and subjecting at least a portion of the induction heatable corner key and at least a portion of each of the first polymer part and the second polymer part to induction heating sufficient to render them molten, terminating the induction heating, and allowing the molten portions to cool and harden.