A welding rod is a generic name that refers to electrodes or filler metal used to join two other base metals. The rods can be consumable or non-consumable; the consumable rods will disintegrate or melt to form the bonding material that holds the two metals together. Non-consumable rods simply provide enough catalytic reaction with the base metals to propagate their fusing in an oxygen-rich atmospheric environment.
Brazing rods are used in the same process that joins two pieces of base metal, the braze flows across the joint and cools to form a solid bond. Brazing creates an extremely strong joint, usually stronger than the base metal pieces.