Lincoln Electric SP 170-I, Operator'S Manual

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Helpful Hints
1. For general welding, it is not necessary to weave
the arc, neither forward or backward nor sideways.
Weld along at a steady pace. You will find it easier.
2. When welding on thin plate, you will find that you
will have to increase the welding speed, whereas
when welding on heavy plate, it is necessary to go
more slowly in order to get good penetration.
3. When welding sheet metal 16 gauge (1.5 mm) and
lighter, heat buildup may cause part warpage and
burn through. One way to eliminate these problems
is to use the back-stepping method illustrated in
Figure B.21.
Practice
The best way of getting practice in the four skills that
enable you to maintain:
1. Correct welding position
2. Correct way to strike an arc
3. Correct electrical stickout
4. Correct welding speed
is to perform the following exercise.
Refer to Figure B.22.
1. Learn to strike an arc by positioning the gun over
the joint and touching the wire to the work.
2. Position face shield to protect face and eyes.
3. Depress gun trigger, hold gun so contact tip to
work distance Is about 3/8 to 1/2 inch (10 to 12
mm) and the gun is at proper angle.
Mild Steel 16 gauge or 1/16 inch
(1.6 mm)
Electrode Lincolnweld 0.025 L-56
electrode
CO
2
Voltage Setting “ V ” C
Wire Feed Speed “ o|o ” 4
For the SP 170-I, use the following:
B-15
SP 170-I
B-15
LEARNING TO WELD
FIGURE B.24
3. The Correct Electrical Stickout (ESO)
The electrical stickout (ESO) is the distance from
the end of the contact tip to the end of the wire.
See Figure B.24.
Once the arc has been established, maintaining
the correct ESO becomes extremely important.
The ESO should be approximately 3/8 to 1/2 inch
(10 to 12 mm) long.
The easiest way to tell whether the ESO is the cor-
rect length is by listening to its sound. The correct
ESO has a distinctive
“ crackling ” sound, very much
like eggs frying in a pan. A long ESO has a hollow,
blowing or hissing sound. If the ESO is too short,
you may stick the contact tip or nozzle to the weld
puddle and/or fuse the wire to the contact tip.
4. The Correct Welding Speed
The important thing to watch while welding is the
puddle of molten metal right behind the arc. See
Figure B.25. Do not watch the arc itself. It is the
appearance of the puddle and the ridge where the
molten Puddle solidifies that indicates correct weld-
ing speed. The ridge should be approximately 3/8
”
(10 mm) behind the wire electrode.
Most beginners tend to weld too fast, resulting in a
thin, uneven,
“ wormy ” looking bead. They are not
watching the molten metal.
FIGURE B.25
Contact Tip
Wire Electrode
ESO
Molten puddle
Base metal
Weld metal ridge