Lincoln Electric AC-235 Manual page 19

WARNING
ARC RAYS can burn.
The carbon arc torch rays will cause severe
arc burns to exposed skin. Therefore, a pair of
work gloves, long sleeved shirt or sleevelets,
and an apron are recommended.
Use an arc welding headshield or hand shield with a No. 11
or No. 12 lens. Oxyacetylene goggles are not sufficient eye
and face protection.
When adjusting the length of carbons, be sure the welder is
turned off. An arc flash while making this adjustment can
burn hands or eyes.
When laying the torch down, avoid touching the carbons to
the grounded bench or work. This is best done by turning
the welder off. As an alternative, either set the torch on an
insulated surface or lay it on its side with the leads hanging
down over the bench so the handle rests on the bench top.
DO NOT EXCEED THE OUTPUT DUTY CYCLE OF
THE WELDER. Exceeding this duty cycle in successive
10 minute periods can overheat the welder and damage the
windings. (See page 8.)
Heat Settings
Recommended current settings for different material thick-
nesses and carbon sizes are given in the table. Generally, use
only enough current to cause the filler metal to flow freely on
the work. Do not use currents so high that the copper coating
burns away more than 1/2'' (12.7mm) above the arc.
Set the carbons to extend about 2" (50mm) beyond the copper jaws.
WARNING
Be sure the welder is turned off when making this
adjustment.
Thickness of Approximate Current
Base Metal
1/32"(0.8)
1/16"(1.6)
1/8"(3.2)
1/4"(6.4)
After adjusting the welder current and setting the carbon
stickout, start the welder and you are ready to go.
Carbon
Setting (AC) Diameter
30-50 amps 1/4"(6.4)
50-60 amps 1/4"(6.4)
70-80 amps 5/16"(7.9)
90-100 amps 3/8"(9.5)
2.00"
0.06"
Use the thumb control on the arc torch to rotate the carbons until
they touch. Start the arc by reversing the thumb control setting
to spread the carbons 1/16 to 3/16" (1.6 to 4.8mm) apart. As the
carbons burn away use the thumb control to maintain the
desired arc. When the proper arc can no longer be maintained,
turn the welder off and readjust the carbon stickout.
A wide, soft, quiet flame gives the best results for most
jobs. When the carbon tips are too close together a small
flame accompanied by a hissing or crackling sound results.
The shape of a good flame is illustrated below. The flame
fans out to form a "fish tail" shape with inner and outer
cone. To heat a crack or a corner, position the flame as illus-
trated.
Heat intensity is controlled by changing the current setting,
by moving the carbons closer together or farther apart, or
by changing the distance between the flame and work.
When the work sets on a metal table, the table absorbs
some of the heat. To avoid high heat loss, the part can be set
on thin metal strips or some insulation.
Removal of Nuts and Bolts: Apply heat with the arc torch
for a few seconds and nuts can be easily turned off.
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