A fastener for splicing wires and the like is mace by forming a tubular sleeve of spring material such as phosphor bronze. In its unrestrained shape, the tubular sleeve is too small to receive the wires, but the tubular sleeve is expanded elastically and held expanded by solder, so that the wires can be inserted. Upon the application of heat the solder melts, flowing into the joint and allowing the sleeve to spring back to its original size or at least to the diameter of the wires. The fastener can be mounted on a stud to provide a replacement for the familiar solder cup terminal. An expanded sleeve can be placed around a piece of heat shrinkable tube. When heated, the tube and the sleeve contract, the sleeve reinforcing the tube giving a much greater compressive force during shrinking. The sleeve then becomes a metallic protector for the tube.