14
The back hand will yield a bead that
is more convex and heavily oxidized. Vertical-up
welding is also the recommended method for copper. The weld should be deposited
as straight stringers
or with a small weaving technique. Wide weaving patterns should be avoided. The
vertical-down technique
may be used for thin materials (under 1/4 in. (6.4mm) thick) but lack of fusion
defects are very likely
to occur. Unlike
all the other materials mentioned, welding in the overhead position is extremely
difficult, although possible.
When it is accomplished, the bead shape and wetting are very poor. This type of
welding should be
avoided if at all possible. Representative
welding conditions for copper materials appear in Table
8-5. Figures 8-10 and 8-11 show accurate
burn-off characteristics for various size copper and silicon-bronze wires and
Figures 8-12 and 8-13
show deposition rates for these wire feed speeds. Figure
8-10 - Burn-Off Characteristics - Deoxidized Copper
Wire Continued
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