Taylor and others - you can get silver solder from any jewelry supply store, or from a local jeweler, come to think.
It is generally sold by the penny weight (dwt) - 20 dwt to a troy ounce (ozt). It comes in three temp ranges, easy, medium, and hard.
The thin sheet can be cut easily, altho a jeweler has a nifty little punch device to make the chads. They are generally about 1/32" x 1/16".
In use, one or more of the little pieces are laid on your heat pad. Used to be asbestos,, don't know what it is now. Clean and flux your pieces, and fit together. Heat the joint are to almost soldering temp. Now, hold something like a scribe in your non-torch hand, and put the flame to the chad - it will form a wee ball. Pick it up with the pointy part of the scribe, and place along the joint while you heat the work area, and when it reaches the soldering temp, touch the little ball to the edge of the joint. Do that as much as necessary, and always the solder will creep into the joint, following wherever you heat. Results in a neat, tidy joint. Works with gold solder when you go to fix your wife's favorite broach.
Oh - pickle when done, removes the flux.