Learn how to heat-harden sterling silver and what common hardness terms mean for fine silver and for sterling.
To harden sterling silver, heat it to 600°F (316°C) for 30–50 minutes in a kiln or furnace. Air-cool the sterling silver before pickling. The hardness will be equal to the hardness achieved by cold-working it to a 50% reduction (or ¾-hard). If you want to make your sterling silver harder than ¾-hard, you must physically reduce the cross-sectional area using the chart below.
|Rockwell Hardness||Common Term||Reduction in Cross-Sectional Area|
|Fine Silver||Sterling Silver||Wire||Sheet|
Example: If you start with a dead-soft wire and reduce the cross-sectional area by drawing it down 50%, your material will become ¾-hard.
This chart shows the Vickers hardness for fine silver, sterling and Argentium® Silver across each common annealing term.
|Vickers Hardness (dph)|
Quickly reference the hardness, Rockwell scale and tensile strength of differently worked silver using this chart.
|Hardness (dph)||Rockwell (15T)||Tensile (PSI)|
Select the best silver solder for the temperature and application you'll be working on with this chart.
When assembling, start with your highest melting point solder. As you assemble each piece, use a lower temperature solder. The chart below describes the uses for and flow temperatures of four standard types of solder.
|Solder||Flow Points||Use for|
|Extra-hard||1490°F/810°C||Laser welding, repair operations|
|Hard||1450°F/788°C||First soldering operations|
|Easy||1325°F/719°C||General soldering and repairs;
intermediate or final operations