A method of forming a joint between a first component and a second component, the first component comprising a plurality of layers of fibers impregnated with a thermosetting matrix. A welding interface element is provided with an array of pointed prongs. One or more of the layers of fibers are penetrated with the prongs, either before or after the fibers have been impregnated with the thermosetting matrix. The first component is cured by heating the thermosetting matrix after the prongs have been embedded. A thermoplastic weld is formed between the second component and the welding interface element.