A soldering iron (and a desoldering iron) with a replaceable tip, which is releasably securable on the forward heat-conducting end of a soldering (or desoldering) iron heat assembly. The tip has a tapered heat conducting core in a tip cap. The face of the core can have a depression for mating engagement with a protrusion of the heat-conducting end. Also, the face can lie in the rear plane of the tip cap. An assembly which allows for the easy removal and application of a replacement tip can include a sleeve with tightening bolt, a coil spring sleeve, or a slotted compressible sleeve. The tip can thus be replaced after it has worn out, and the heat assembly unit need not be replaced until it has burnt out. Methods of manufacturing and using the tip are also disclosed.