Weld Mold 309 description: Weld Mold 309 stainless deposits a smooth, porosity-free, austenitic stainless bead in the 25% chrome and 12% nickel range. This wire is for welding 309 types stainless to itself or to alloyed steels. They also can be used for welding 301, 302, 304, 305 and 308 type stainless steels. 309 also welds many combinations of dissimilar metals.