Metals such as copper, brass and steel can be bonded together with a filler metal by brazing or soldering. Unlike welding, the metals bonded don't have to get hot enough to melt. Only the filler metal needs to melt.
Soldering and Brazing
The American Welding Association describes soldering as fusing metals using a filler metal that melts under 449 degrees Celsius, and brazing as melting at over 840 degrees.
Soldering and Silver Soldering
"Soft" solders melt at around or under 243 degrees Celsius. "Hard" solders--sometimes called "silver" solders because of increasing amounts of silver--melt at between 243 and 448 degrees C.
Soft Silver Solders
Soft silver solder contains as little as .03 per cent silver and as much as five per cent. Adding silver to tin-based soft solder improves its flowing ability and increases the strength of the joint.
Hard Silver Solder
Hard silver solder contains from 20 to 40 per cent silver. Using these solders makes a much stronger joint than soft solder.
Brazing rods, usually made of brass, can have as much as 80 per cent silver for certain applications. Other metals used in brazing rods are copper, palladium and special alloys. Brazing rods make the strongest joints.