cases. The purity of this grade of iron gives a homogeneous, soft weld of
even texture, great ductility and exceptionally good machining qualities.
For welding heavy steel castings, a rod of rolled carbon steel is employed.
For working on high carbon steel, a rod of the steel being welded must be
employed and for alloy steels, such as nickel, manganese, vanadium, etc.,
special rods of suitable alloy composition are preferable.

Aluminum welding rods are made from this metal alloyed to give the even
flowing that is essential. Aluminum is one of the most difficult of all the
metals to handle in this work and the selection of the proper rod is of
great importance.

Brass is filled with brass wire when in small castings and sheets. For
general work with brass castings, manganese bronze or Tobin bronze may be
used.

Bronze is welded with manganese bronze or Tobin bronze, while copper is
filled with copper wire.

These welding rods should always be used to fill the weld when the
thickness of material makes their employment necessary, and additional
metal should always be added at the weld when possible as the joint cannot
have the same strength as the original piece if made or dressed off flush
with the surfaces around the weld. This is true because the metal welded
into the joint is a casting and will never have more strength than a
casting of the material used for filling.

Great care should be exercised when adding metal from welding rods to make
sure that no metal is added at a point that is not itself melted and molten
when the addition is made. When molten metal is placed upon cooler surfaces