Weld Mold 4333 description: Weld Mold 4333 is a pure deoxidized material with no oxide or nitrite inclusions. This material is for welding pure deoxidized, tough pitch and electrolytic copper. Also for bronze and structural shapes, buss bars, rotors, copper containers and all copper units where high electrical conductivity is a prime requisite. It will also join copper to steel. When welding material as thick as 3/16″ pre-heat between 100F and 200F. Material over 3/16″ thick should be pre-heated between 200 F to 1,000 F.