Medium solder is the middle grade in the stepped sequence of gold and silver solder alloys used in traditional bench jewellery. Each grade in the sequence is formulated to flow at a different temperature, allowing a jeweller to assemble a piece in successive operations without the heat applied to a later joint melting an earlier one. The standard sequence in gold work runs from extra-hard solder (about 800 °C) through hard, medium, and easy down to extra-easy (about 650 °C); in silver work the temperatures are similar but slightly lower across the sequence.

How the sequence is used

A typical assembly proceeds from highest melting point to lowest. Hard solder is used for the first and most demanding joints — the principal structural joins of a setting, a head, or a frame. Medium solder follows for second-stage operations: attaching shoulders to a shank, soldering on bezels and gallery components, joining bridges and crossbars where the hard-soldered structure must remain intact. Easy solder handles the final delicate operations such as setting prongs, attaching findings, and chain repair.

For gold work, medium solder typically flows at about 730 to 760 °C, depending on the karat and the formulator. The melting range is narrow enough to give the jeweller a workable temperature window while sufficiently below the hard-solder flow point to leave earlier joints undisturbed. Silver medium solder flows at approximately 720 to 740 °C, with similar relationships to silver hard and easy solders.

Composition and karat matching

Solder for karat-gold work is itself karat-rated to match the metal being soldered. A 14-karat yellow gold piece is soldered with 14-karat yellow solder; an 18-karat white gold piece with 18-karat white solder. The solder's melting point is reduced relative to the parent metal by adjustments to the alloy composition — typically by additions of zinc, cadmium (in older formulations, now restricted), and lower-melting metals — that lower the flow point without compromising the colour match too noticeably.

Silver solder follows the same logic but with a more limited karat consideration. Sterling silver solder in hard, medium, and easy grades is the standard for fine silver work; silver brazing alloys for industrial applications follow a separate sequence with higher melting points and different compositional considerations.

Practical bench considerations

Successful stepped soldering requires careful work practice. The piece must be cleaned of flux residue between operations to allow new solder to flow. Heat must be applied locally to the new joint rather than soaking the entire piece, both to economise on fuel and to keep earlier joints below their flow temperatures. A torch with a fine flame and the ability to direct heat precisely is more important than raw heat output for stepped-solder work.

Medium solder is one of the standard supplies in any working bench, alongside hard, easy, and the occasional extra-easy or extra-hard grade for specific operations. The solder is supplied as wire, sheet, or paste, with the choice depending on the application — wire and sheet for general bench use, paste for setting work and for situations where precise placement of a small quantity is needed.

Further reading

• Ganoksin — soldering reference articles
• GIA Gems & Gemology — manufacturing technique articles
• Rio Grande — solder product references