Soldering is a very important process in jewellery manufacture for joining various component parts into the finished piece. It involves heating the pieces to be joined and applying the solder alloy, which melts and runs along the joint gap. Heating is typically by gas torch although oil lamps and blowpipes are still to be found in workshops. For mass production, soldering can be done in a belt furnace.

Whilst soldering remains the dominant technique, increasing use of laser welding is an alternative approach especially in chain manufacture and for repair work, where heating by the soldering torch may damage gem stones. For most jewellery, solders should be of the same caratage as the jewellery, although there are some exceptions allowed by law in some countries. Many solders have traditionally contained cadmium but this is increasingly beinig banned under national legislation because of health and safety problems associated with cadmium fume. Alternative cadmium-free solders in the full range of caratages are available. See Carat Gold Solders.