A backing (strip) is a piece of metal that is placed on the backside of a weld joint to prevent the molten metal from dripping through the open root (burn through). It helps to ensure that 100% of the base metal’s thickness is fused by the weld (full penetration). The backing may be either left on the finished (cofferdam or void space closing welds without both-sides accessibility) weld or removed following welding (Ceramic backing, Copper strips). If the backing is to be removed, the letter R is placed in the backing symbol.  The backing is often removed from a finished weld … Continue reading Backing in welding