The plumbers solder with silver in it is referred to as Silver Bearing solder. 420-460 degrees F melting temps. Home Disappointment carries it.
Jewelry grade Silver Solders have melting points just below pure silver in the 1350 degree F range. Using these solders can result in annealing the metal, which may not be desirable. Use caution relying on shock quenching which can open pinholes. I use a hot pickle to quench and clean off the melted on flux and coatings I apply. Mixing powered boric acid in denatured alcohol to make a paste. Apply and burn off alcohol then using a soft flame melt the boric acid to your metal will prevent most discoloration. Powdered not granular BA is available at pharmacies.
However coating with Battern's self pickling flux can protect the temper, if you are quick. The solders I used were 80 -90% silver because I didn't want visible seams in my silver work. The softer (lower temp) the solder the less silver and more non-silvery metal that can be seen. Solders tend to oxidize faster too.
My present source for supplies:
Silver bearing solders are stronger and much more suited for building than the rosin core electrical solders. Most electrical connections are arranged so that the joint does not support the connection.
Only boilers require Silver Solders for strength more than melting temp.