Lead Wool

Lead wool is made by scratching fine strands from the surface of a Lead disc. It is used for the caulking of joints in large pipes e.g. gas mains and in some specialist batteries.
Lead Wool, a form of caulking Lead, is long, fine strands of chemical grade Lead which is twisted into 58”rope for use in various applications and is available in 5 lb. cartons or 50 lb. waterproof bags. It averages about 2-½ ft. to one pound. Lead wool is certified to meet Federal Specification QQ-C-40.
The Lead wool is used to seal flanged connections, cast iron, cement and earthenware pipes, and apertures of walls and ceilings. Very good ductility of Lead ensures fast and easy filling and sealing of small slots too. It is also convenient for anti-radiation protection. The Lead resistance to aggressive environment is a warranty of long-term durability of seal.
Lead wool, a loose rope of fibers, is produced by passing molten Lead through a fine sieve and allowing it to solidify. When forced into a crevice under considerable force, the fibrous rope cold welds into a homogeneous mass, forming a solid metal seal. This caulking process is useful where temperature or explosion hazards prohibit the use of flame heating. The gaps between Lead shielding sheets in nuclear submarines are often filled and caulked with Lead wool. It is more convenient to use than molten Lead for caulking purposes because it requires no heating or pouring. Lead Wool properly packed is ideal for caulking and makes a tighter seal than molten Lead which shrinks slightly after casting.