A tungsten bar can refer to different things, either a tungsten bucking bar or a bar of the metal tungsten. A tungsten bucking bar is a heavy-duty tool used in the process of riveting metal together, and bars of tungsten are used to store and transport the heavy metal.
Not all bucking bars are made of tungsten, but because they face a lot of wear and tear, tungsten is a popular metal to use due to its strength and relatively low price. Bucking bars are placed behind where the rivet is to go in order to counter movement from the front and keep the back of the rivet in place. Due to the density of tungsten, which is 0.36 percent less dense than gold, bars of tungsten are sometimes gold plated and sold as authentic gold bars.