If your flow point of solder matches or exceeds sterling silver or gold flow/melt temps you should not need solder. You would be fusing the metal.
Fusing metal occurs just below melt temp. Melting occurs at melt temp. There is a fine line.
Solder comes and can be made to flow at many flow temps.
If there is only one solder joint on your piece you can use any compatible solder for your metal type. For maximum strength I would use as high melt temp solder that I had available and that was compatible with my parent metal.
If you are assembling multiple pieces together in one piece you will want to start off with “Hard” solder and move to an “easy” solder as you assemble the work.
~You may also want to coat your finished solder joints with something to help prevent them from flowing as you move to the easy/lowTemp flow solders.
The flow point of the solder remains below the melt temp of the parent metal.
This chart link should help: https://www.riogrande.com/article?name=Selecting-Silver-Solder-CGl
| Solder | Flow Points | Use for |
|---|---|---|
| Extra-hard | 1490°F/810°C | Laser welding, repair operations |
| Hard | 1450°F/788°C | First soldering operations |
| Medium | 1360°F/738°C | General soldering; |
| intermediate operations | ||
| Easy | 1325°F/719°C | General soldering and repairs; |
| intermediate or final operations | ||
| Extra-easy | 1207°F/653°C | Final soldering |
More resources from Rio Grande: https://www.riogrande.com/category/resource-center/search-results?queryTerm=solder&tags=&contentTypes=&pageSize=32&categoryId=&page=1&searchType=1
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