Ceramic Backing

Ceramic backings are inserts that you place on the back side of the joint. They shield the weld root from oxygen and prevent the root from burning through or dripping. You mainly use them for root welding when you can't access one side. Just insert them cleanly, press them in place, and then weld over the joint. The backing melts along and forms a smooth root. If it's positioned incorrectly or the gap doesn't fit, the root will be unclean and you'll get lack of fusion defects.