Those stick things that weld stuff.
To join two pieces of metal together by welding, an electrode is required to conduct the current through the workpiece to fuse two parts into one. They can either be consumable or non-consumable. Consumable rods are made of several compounds. As the current forms an electric arc between the material and the electrode, the coating of the electrode melts and puts a layer of slag in the material to protect and join it with the other piece.
Sold in most hardware stores.