The Correct Way To Strike An Arc; The Correct Contact Tip To Work Distance; The Correct Welding Speed (Travel Speed) - Lincoln Electric LTW1 Manual De Instrucciones

LEARNING TO WELD
WARNING
ARC RAYS can burn eyes and skin.
When using an open arc process, it Is
necessary to use correct eye, head and
body protection.
Protect yourself and others, read "ARC RAYS can burn" at
the front of the Operators Manual supplied with welder.

2. The Correct Way To Strike An Arc

1. Be sure the work clamp makes good electrical contact to
the work.
2. Position gun over joint. End of wire may be lightly touch-
ing the work.
3. Position face shield to protect face and eyes, close gun
trigger, and begin welding. Hold the gun so that the con-
tact tip to work distance is about 3/8" to 1/2"
(10 – 12 mm).
4. To stop welding, release the gun trigger and the pull the
gun away from the work after the arc goes out.
5. A ball may form at the tip end of the wire after welding.
For easier restrikes (with Innershield wire), the ball may
be removed by feeding out a few inches of wire and sim-
ply bending the wire back and forth until it breaks off.
6. When no more welding is to be done, turn off the
machine.
3. The Correct Contact Tip to Work Distance (CTWD)
The Contact Tip to Work Distance (CTWD) is the distance from the end
of the contact tip to the work.
See Figure 13.
Once the arc has been established, maintaining the correct CTWD
becomes extremely important. The CTWD should be approximately
3/8" to 1/2" (10 to 12 mm) long.
FIGURE 13
Contact Tip
Wire Electrode
The easiest way to tell whether the CTWD is the correct length is by
listening to its sound. The correct CTWD has a distinctive "crackling"
sound, very much like eggs frying in a pan. A long CTWD has a hollow
blowing or hissing sound. If the CTWD is too short, you may stick the
contact tip or nozzle to the weld puddle or both fuse the wire to the
contact tip.

4. The Correct Welding Speed (Travel Speed)

The important thing to watch while welding is the puddle of molten
metal right behind the arc. See Figure 14. Do not watch the arc itself.
It is the appearance of the puddle and the ridge where the molten
puddle solidifies that indicates correct welding speed. The ridge
should be approximately 3/8" (10 mm) behind the wire electrode.
Welding too fast is a common problem. Pay attention to the molten
bead that forms as you weld. If you notice that your bead is thin,
uneven, and wormy looking, reduce your travel speed.
FIGURE 14
3/8 - 1/2" (10 - 12 mm)
(CTWD)
7
Solidifying ridge
Molten puddle
Direction of Travel