Care must be used to see that the work is supported so that it will
maintain the same relative position between the parts as must be present
when the work is finished. In this connection it must be remembered that
the expansion of the metal when heated may be great enough to cause serious
distortion and to provide against this is one of the difficulties to be
overcome.
Perfect alignment should be secured between the separate parts that are to
be joined and the two edges must be held up so that they will be in the
same plane while welding is carried out. If, by any chance, one drops
below the other while molten metal is being added, the whole job may have
to be undone and done over again. One precaution that is necessary is that
of making sure that the clamping or supporting does not in itself pull the
work out of shape while melted.
TORCH PRACTICE
[Illustration: Figure 34.--Rotary Movement of Torch in Welding]
The weld is made by bringing the tip of the welding flame to the edges of
the metals to be joined. The torch should be held in the right hand and
moved slowly along the crack with a rotating motion, traveling in small
circles (Figure 34), so that the Welding flame touches first on one side of
the crack and then on the other. On large work the motion may be simply
back and forth across the crack, advancing regularly as the metal unites.
It is usually best to weld toward the operator rather than from him,
although this rule is governed by circumstances.
Pages:
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119