Lincoln Electric LTW1 User Manual
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“LEARNING TO WELD”
“APRENDIENDO A SOLDAR”
“APPRENEZ À SOUDER”
WORKPIECE
ARC
ARCO
ARC
WORK CLAMP
PINZA DE TRABAJO
BRIDE DE TRAVAIL
GUN AND CABLE
ANTORCHA Y CABLE
PISTOLET ET C BLE
PIEZA DE TRABAJO
MORCEAU DE TRAVAIL
May, 2006
LTW1
Copyright © 2006 Lincoln Global Inc.
Safety Depends on You
Lincoln arc welding and cutting equipment
is designed and built with safety in mind.
However, your overall safety can be
increased by proper installation ... and
thoughtful operation on your part. DO NOT
INSTALL, OPERATE OR REPAIR THIS
EQUIPMENT WITHOUT READING THE
OPERATORS MANUAL WHICH IS PROVIDED WITH YOUR MACHINE AND THE
SAFETY PRECAUTIONS CONTAINED
THROUGHOUT. And, most importantly,
think before you act and be careful.
La seguridad depende de usted
El equipo de soldadura por arco y corte de
Lincoln está diseñado y construido teniendo
en mente la seguridad. Sin embargo, la
seguridad general puede ser mejor si instala
y opera la máquina adecuadamente.
NO
INSTALE, NO PONGA EN FUNCIONAMIENTO NI REPARE ESTE EQUIPO
SIN LA LECTURA DEL MANUAL DE LOS
OPERADORES QUE SE PROPORCIONA
CON SU MÁQUINA Y LAS MEDIDAS DE
SEGURIDAD CONTENIDAS EN EL MISMO.
Lo más importante, piense antes de actuar
y tenga cuidado.
La sécurité dépend de vous
Le matériel de soudage et de coupage à
l'arc Lincoln est conçu et construit en tenant
compte de la sécurité. Toutefois, la sécurité
en général peut être accrue grâce à une
bonne installation... et à la plus grande prudence de votre part.
NE PAS INSTALLER,
N'ACTIONNEZ PAS OU NE RÉPARER PAS
CET EQUIPEMENT SANS LIRE LE MANUEL
D'OPÉRATEURS QUI EST EQUIPEMENT DE
VOTRE MACHINE ET DE MESURES DE
SÉCURITÉ CONTENUES PARTOUT.
Et, par
dessus tout, réfléchissez avant d'agir et
exercez la plus grande prudence.
RETURN TO MAIN MENU
1
1
TABLE OF CONTENTS
Page
Learn to Weld.................................................................................................................2
Arc Welding Circuit....................................................................................................2
Self-Shielded FCAW (Flux Core Arc Welding)..........................................................3
GMAW (Gas Metal Arc Welding) ..............................................................................3
Process Selection......................................................................................................4
For GMAW (MIG) Process..................................................................................4
For FCAW (Innershield) Process........................................................................4
Common Metals..................................................................................................4
Joint Types and Positions .........................................................................................4
Butt Joints...........................................................................................................4
Penetration .........................................................................................................5
Fillet Joints..........................................................................................................5
Welding In The Vertical Position ...............................................................................5
Vertical-up And Overhead Welding ....................................................................5
Vertical-down Welding........................................................................................6
Machine Set Up For The Self-Shielded FCAW Process...........................................6
Welding Techniques For The Self-Shielded FCAW Process....................................6
1. The Correct Welding Position.........................................................................6
2. The Correct Way To Strike An Arc .................................................................7
3. The Correct Contact Tip To Work Distance....................................................7
4. The Correct Welding Speed (Travel Speed)...................................................7
Helpful Hints..............................................................................................................8
Practice .....................................................................................................................8
Machine Set Up For The GMAW (MIG) Process ......................................................9
Weld Techniques For The GMAW (MIG) Process....................................................9
1. The Correct Welding Position.........................................................................9
2. The Correct Way To Strike An Arc .................................................................9
3. The Correct (CTWD) Contact Tip To Work Distance....................................10
4. The Correct Welding Speed ........................................................................10
Helpful Hints............................................................................................................10
Practice ...................................................................................................................10
Troubleshooting Welds ..............................................................................................11
2
LEARNING TO WELD
2
LEARNING TO WELD
Welding is a skill that can only be learned by practicing. No one can become an accomplished welder
simply by reading about it. The following pages will
help the inexperienced operator to understand the
basics about wire welding and provide guidance to
help develop this skill. For more detailed information,
order a copy of “New Lessons in Arc Welding”.
THE ARC-WELDING CIRCUIT
The operators knowledge of arc welding must go
beyond the arc itself. The operator must know how to
control the arc, and this requires a knowledge of the
welding circuit and the equipment that provides the
electric current used in the arc. Figure 1 illustrates the
welding circuit for a typical welding machine. The circuit begins where the gun cable is attached to the
welding machine. Current flows through the gun
cable, gun, and contact tip, to the wire and across the
arc. On the work side of the arc, current flows through
the base metal to the work cable and back to the
welding machine. This circuit must be complete for the
current to flow. Loose or poor connections anywhere
in the circuit will rob voltage from the arc and cause it
to become erratic.
This machine’s welding circuit has a voltage output of
32 volts DC maximum. This voltage is quite low and is
only present when the gun trigger is pressed.
FIGURE 1
To weld, the work clamp must be tightly connected to
clean base metal. Clean the joints by removing
excessive scale, rust, moisture, paint, oil and grease
from the surface. As with all welding applications, joint
cleanliness is necessary to avoid porosity and to
attain the best weld quality. Connect the work clamp
“as close as possible” to the area you wish to weld.
This helps prevent current from going through an
unwanted path. Avoid allowing the welding circuit to
pass through hinges, bearings, electronic components, or similar devices that can be damaged. See
Figure 2. Always disconnect electrical devices before
welding upon them.
FIGURE 2
Fumes and slag generated from
Innershield type electrodes recommended for use with this welding
machine can produce fumes and
gases hazardous to your health.
• Avoid contact with eyes and skin.
• Do not take internally.
• Keep slag away from children.
• Keep out of reach of children.
• Follow all safety precautions found in your
operator’s manual.
-----------------------------------------------------------------------
The gun and cable assembly is held by the operator
who guides the automatically fed wire along the joint,
maintaining a contact tip to work distance of about 3/8
to 1/2 inch (10 – 12 mm) This is called Contact Tip to
Work Distance. The welding arc is established in the
gap between the work and the end of a small diameter wire. When the power source is properly set, the
length of the arc is maintained automatically.
Arc welding is a manual skill requiring a steady hand,
good physical condition, and good eyesight. The operator controls the welding arc, and, therefore, the quality of the weld made.
WRONG
WRONG
CURRENT
CURRENT
PATH
TH
Bearings
Hinges
Electrical Components
CORRECT
CORRECT
CURRENT
CURRENT
PATH
TH
*
* For best results position work clamp approximantely
12 inches(294mm) from the welded area.
WARNING
WORKPIECE
ARC
GUN and CABLE
WORK CLAMP
3
LEARNING TO WELD
3
SELF-SHIELDED FCAW (FLUX CORE
ARC WELDING)
Figure 3 illustrates the action taking place in the selfshielded FCAW (Innershield) welding arc. It closely
resembles what is actually seen while welding.
FIGURE 3
The “arc stream” is seen in the middle of the picture.
This is the electric arc created by the electric current
flowing through the space between the end of the wire
electrode and the base metal. The temperature of this
arc is about 6000°F, which is more than enough to
melt metal.
The arc is very bright, as well as hot, and cannot be
looked at with the naked eye without risking painful
injury. A very dark lens, specifically designed for arc
welding, must be used with the hand or face shield
whenever viewing the arc .(ANSI Z49.1-88)
The arc melts the base metal and actually digs into it
much as water through a nozzle on a garden hose
digs into the earth. The molten metal forms a molten
pool or crater and tends to flow away from the arc. As
it moves away from the arc, it cools and solidifies.
The function of the Innershield cored wire electrode is
much more than simply to carry current to the arc. The
wire core is composed of fluxes and/or alloying ingredients around which a steel sheath has been formed.
It is simply a stick electrode turned inside out in a continuous wire form.
The cored wire melts in the arc and tiny droplets of
molten metal shoot across the arc into the molten
pool. The wire sheath provides additional filler metal
for the joint to fill the groove or gap between the two
pieces of base metal.
The core materials also melt or burn in the arc and
perform several functions. They make the arc steadier, provide a shield of smoke-like gas around the arc
to keep oxygen and nitrogen in the air away from the
molten metal, and provide a flux for the molten pool.
The flux picks up impurities and forms the protective
slag on top of the weld during cooling.
After running a weld bead, the slag may be removed
with a chipping hammer and wire brush. This
improves appearance and allows for inspection of the
finished weld.
Since machine size and output characteristics limit the
size and type of wire electrode which can be used, check
your Instruction Manual “Application Chart” or see the
Application Guide on the inside door of the Machine. This
will give you the proper electrode size and control settings to be used.
GMAW (GAS METALARC WELDING)
Figure 4 illustrates the GMAW (Also referred to as MIG)
welding arc. Solid wire does not contain fluxes or ingredients to form its own shielding and no slag forms to protect the molten weld metal. For this reason, a continuous
even flow of shielding gas is needed to protect the
molten weld metal from atmospheric contaminant’s such
as oxygen and nitrogen. Shielding gas is supplied
through the gun and cable assembly, through the gas
nozzle and into the welding zone.
Important!
The MIG welding process requires that the welder has a
gas solenoid valve installed in order to control the flow of
the shielding gas. Read your Operators Manual to see if
your machine requires additional items to MIG weld.
When comparing the GMAW and FCAW processes, you
can see that the principal difference between the two lies
in the type of shielding used. GMAW uses gas for shielding, thus we have Gas Metal Arc Welding. FCAW uses
the melting or burning of the core ingredients for shielding, and is thus termed Self-Shielded Flux-Cored Arc
Welding.
The recommended LINCOLN Super Arc L-56 solid wire
and gas for Gas Metal Arc Welding (MIG)Metal Inert Gas
is also located in the Instruction Manual “Application
Chart” or see the Application Guide on the inside door of
the Machine. This machine is capable of welding a wide
range of mild steels in all positions, however, more skill
IS required for out-of-position welding with the GMAW
process.
FIGURE 4
Gas nozzle
Shielding gasSolid wire
electrode
Contact Tip
Base metal
Weld metal
Burning of core materials
inside the wire electrode
provides a gas to shield
the molten metal as it
solidifies.
Arc Stream
Weld Puddle
Cored Wire
Protective Slag
Weld Metal
DRAG TECHNIQUE
PUSH TECHNIQUE
DIRECTION OF TRAVEL
DIRECTION OF TRAVEL
WARNING
4
LEARNING TO WELD
4
PROCESS SELECTION
By gaining knowledge of the differences between the
two processes, you will be able to select the best
process for the job you have at hand. In selecting a
process, you should consider:
For GMAW (MIG) Process
1. Is most of my welding performed on 16 gauge and
lighter materials?
2. Can I afford the extra expense, space, and lack of
portability required for gas cylinders and gas supply?
3. Do I require clean, finished-looking welds?
4. Base metal must be clean.
If you have answered yes to all the above questions
GMAW may be the process for you. If you have
answered no to any of the above questions, then you
should consider using the FCAW process.
For FCAW (Innershield) Process
1. Do I want simplicity and portability?
2. Will welding be performed outdoors or under windy
conditions?
3. Do I require good all position welding capability?
4. Will most welding be performed on 16 gauge and
heavier, somewhat rusty or dirty materials?
5. Weld must be cleaned prior to painting.
6. Please note that your machine may or may not be
set up to handle both FCAW and GMAW welding
processes. Refer to your “Operators Manual” to
determine Option Accessories are required to adapt
to your machine.
COMMON METALS
Most metals found around the farm, small shop or
home are low carbon steel, sometimes referred to as
mild steel. Typical items made with this type of steel
include most sheet metal, plate, pipe and rolled
shapes such as channels and angle irons. This type of
steel can usually be easily welded without special precautions. Some steels, however, contain higher carbon levels or other alloys and are more difficult to
weld. Basically, if a magnet sticks to the metal and
you can easily cut the metal with a file, chances are
good that the metal is mild steel and that you will be
able to weld the material. If you plan to weld on aluminum, special drive rolls or aluminum Welding Kits
may be required or highly recommended. Consult
your machines Operators Manual. Pure Argon shielding gas and a spool of aluminum welding wire will also
be required. For further information on identifying various types of steels and other metals, and for proper
procedures for welding them, we again suggest you
purchase a copy of “Metals and How to Weld Them”.
Regardless of the type of metal being welded, in order
to get a quality weld, it is important that the metal is
free of oil, paint, rust or other contaminant’s.
JOINT TYPES AND POSITIONS
Five types of welding joints are: Butt joint, Fillet joint,
Lap joint, Edge joint and Corner joint. See Figure 5.
Of these, the Butt Joint and Fillet Joint are the two
most common welds.
FIGURE 5
Butt Joints
Place two plates side by side with a tight Fit-up to prevent burn thru when welding.
Securely clamp or tack weld the plates at both ends,
otherwise the heat will cause the plates to move apart.
See Figure 6.
Now weld the two plates together. Weld from left to
right (if right handed). Point the wire electrode
between the two plates, keeping the gun slightly tilted
in the direction of travel. Watch the molten metal to be
sure it distributes itself evenly on both edges and in
between the plates. This is referred to as the “pull
technique”. On thin gauge sheet metal, use the “push
technique”. See “Welding Techniques for GMAW
(MIG) Process”.
FIGURE 6
Butt joint Lap joint
Edge joint Fillet joint Corner joint
5
LEARNING TO WELD
5
Penetration
Unless a weld penetrates close to 100% of the metal
thickness, a butt joint will be weaker than the material
welded together. In the example shown in Figure 7,
the total weld is only half the thickness of the material
thus the weld is only approximately half as strong as
the metal.
FIGURE 7
FIGURE 8
In the example shown in Figure 8, the joint has been
welded so that 100% penetration could be achieved.
The weld, if properly made, is as strong as or stronger
than the original metal.
Fillet Joints
When welding fillet joints, it is very important to hold
the wire electrode at a 45° angle between the two
sides or the metal will not distribute itself evenly. The
gun nozzle is generally formed at an angle to facilitate
this. See Figure 9.
FIGURE 9
Welding In The Vertical Position
Welding in the vertical position can be done either vertical-up or vertical-down. Vertical-up is used whenever
a larger, stronger weld is desired 1/4”(6.4mm) and
thicker material. Vertical-down is used primarily on
sheet metal 3/16”(4.8mm)and thinner materials cause
for fast, low penetrating welds.
Use of this unit on thicker materials than recommended may result in welds of poor quality. The
welds may appear to be fine, but may lack the
fusion or bonding necessary to give a strong
weld. This is called "Cold Casting" or "cold lapping" and is some what similar to a cold solder
joint. Weld failure may result.
------------------------------------------------------------------------
Vertical-up And Overhead Welding
The problem, when welding vertical-up 1/4”(6.4mm)
and thicker material, is to put the molten metal where
it is wanted and make it stay there. If too much molten
metal is deposited, gravity will pull it down wards and
make it “drip”. Therefore, a certain technique has to
be followed.
When welding out-of-position, run stringer beads.
Don’t whip, break the arc, move out of the puddle, or
move too fast in any direction. Use Wire Feed Speed
(WFS) in the low portion of the range. The general
technique and proper gun angle is illustrated in Figure
10.
Generally, keep the electrode nearly perpendicular to
the joint as illustrated. The maximum angle above perpendicular may be required if porosity becomes a
problem.
FIGURE 10
45¡ CENTER LINE
TO HORIZONTAL PLATE
WARNING
PROPER GUN ANGLE
FOR GMAW PROCESS
WELDING IN THE VERTICAL DOWN POSITION
3/16 INCH AND THINNER
1/4 INCH AND THICKER
PROPER GUN ANGLE
FOR FCAW PROCESS
WELDING IN THE VERTICAL UP POSITION
45° CENTERLINE OF GUN TO
HORIZONTAL PLATE
6
LEARNING TO WELD
6
Vertical-down Welding
Refer to Figure 11 Vertical-down welds are applied at
a fast pace. These welds are therefore shallow and
narrow and, as such, are excellent for sheet metal.
Vertical-down welds may be applied by a table which
is found in the Instruction Manual for lighter material.
Use stringer beads and tip the gun in the direction of
travel so the arc force helps hold the molten metal in
the joint. Move as fast as possible consistent with
desired bead shape.
The important thing is to continue lowering the entire
arm as the weld is made so the angle of the gun does
not change. Move the electrode wire fast enough that
the slag does not catch up with the arc. Vertical-down
welding gives thin, shallow welds. It should not be
used on heavy material where large welds are
required. Use the vertical up technique for where large
welds are required.
FIGURE 11
MACHINE SET UP FOR THE
SELF-SHIELDED FCAW PROCESS
1. See PROCESS GUIDELINES in the OPERATION
section for selection of welding wire and voltage,
and for range of metal thicknesses that can be
welded.
2. See the Application Guide on the inside of wire
feed section door for information on setting the
controls.
3. Set the “Voltage” and “Wire Speed” controls to the
settings suggested on the Application Guide for the
welding wire and base metal thickness being used.
The voltage control is marked “V” and the wire feed
speed is marked “olo.”
4. Check that the polarity is correct for the welding
wire being used. Set the polarity for DC(–) when
welding with Innershield NR-211-MP electrode.
See Work Cable Installation in the INSTALLATION
section for instructions on changing polarity.
5. When using Innershield electrode, the gasless nozzle may be used instead of a gas nozzle to improve
visibility of the arc.
6. Connect work clamp to metal to be welded. Work
clamp must make good electrical contact to the
work piece. The work piece must also be grounded
as stated in the “Arc Welding Safety Precautions”
at the beginning of the Instruction Manual which is
supplied with each welder.
WELDING TECHNIQUES FOR THE SELFSHIELDED FCAW PROCESS
Four simple manipulations are of prime importance
when welding. With complete mastery of the four,
welding will be easy. They are as follows:
1. The Correct Welding Position
Figure 12 illustrates the correct welding position for
right handed people. (For left handed people, it is
the opposite.)
Hold the gun (of the gun and cable assembly) in
your right hand and hold the shield with your left
hand. (Left handers simply do the opposite.)
When using the FCAW Process, weld from left to
right (if you are right handed). This enables you to
clearly see what you are doing. (Left handers do
the opposite.) Tilt the gun toward the direction of
travel holding the electrode at an angle as shown
in Figure 12.
FIGURE 12
7
LEARNING TO WELD
7
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 Instruction 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 touching the work.
3. Position face shield to protect face and eyes,
close gun trigger, and begin welding. Hold the
gun so that the contact tip to work distance is
about 3/8 to 1/2 inch (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 simply 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 inch
(10 to 12 mm) long.
FIGURE 13
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 and/or 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.
Most beginners tend to weld too fast, resulting in a
thin uneven, “wormy” looking bead. If this occurs
slow down your travel speed.
FIGURE 14
WARNING
Contact Tip
Wire Electrode
3/8 - 1/2" (10 - 12 mm)
(CTWD)
Solidifying ridge
Molten puddle
Direction of Travel
8
LEARNING TO WELD
8
Helpful Hints
• 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.
• 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.
• 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 15.
FIGURE 15
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 Contact Tip to Work Distance.
4. Correct welding speed is to perform the following
exercise. Refer to Figure 16. Use PROCESS
GUIDELINES in the Instruction Manual and
Application Guide on the inside of wire feed section
door for selection of welding wire, wire feed speed,
voltage, and for range of metal thicknesses that
can be welded.
1. Position face shield to protect face and eyes.
2. Learn to strike an arc by positioning the gun over
the joint and touching the wire to the work.
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.
4. After you strike the arc, practice the correct CTWD.
Learn to distinguish it by its sound.
5. When you are sure that you can hold the CTWD,
with a smooth “crackling” arc start moving. Look at
the molten puddle constantly, and look at the
“ridge” where the metal solidifies.
6. Run beads on a flat plate. Run them parallel to the
top edge (the edge farthest away from you). This
gives you practice in running straight welds, and
also gives you an easy way to check your
progress. The 10th weld will look considerably better than the first weld. By constantly checking on
your mistakes and your progress, welding will soon
be a matter of routine.
First weld from A to B; then from C to A; then
from D to C; then from E to D, and so on.
BACDE
Back-Stepping
Contact
Tip
Gun Angle
CTWD
15°-20°
Direction of Travel
FIGURE 16
Example of good consistent welding beads
after practicing.
9
LEARNING TO WELD
9
MACHINE SET UP FOR THE GMAW (MIG)
PROCESS
1. See APPLICATION CHART in the OPERATION
section or Application Chart on the inside of wire
feed section door for selection of welding wire and
shielding gas, and for range of metal thicknesses
that can be welded. Also setting the proper controls, Drive Roll Orientation and Output Polarity.
2 Set the “Voltage” and “Wire Speed” controls to the
settings suggested on the Application Guide for the
welding wire and base metal thickness being used.
The voltage control is marked “V” and the wire feed
speed is marked with the icon “olo.’’
3 Check that the polarity is correct for the welding
wire being used. Set the polarity for DC(+) when
welding with the GMAW (MIG) process. See
INSTALLATION section of the Operators Manual
for instructions for changing polarity.
4. Check that the gas nozzle and proper size liner
and contact tip are being used and that the gas
supply is turned on. If adjustable, set for 30 to 40
cubic feet per hour (7 to 10 l/min..) under normal
conditions, increase to as high as 45 CFH (17
I/min.) under drafty (slightly windy) conditions.
5. Connect work clamp to metal to be welded. Work
clamp MUST make good electrical contact to the
work piece. The work piece must also be grounded
as stated in the “Arc Welding Safety Precautions”
at the beginning of the Instruction Manual which is
supplied with each welder.
WELDING TECHNIQUES FOR THE GMAW
(MIG) PROCESS
Four simple manipulations are of prime importance
when welding. With complete mastery of the four,
welding will be easy. They are as follows:
1. The Correct Welding Position
Figure 17 illustrates the correct welding position for
right handed people. (For left handed people, it is
the opposite.)
When GMAW (MIG) welding on sheet metal, it is
important to use the “forehand” push technique.
Hold the gun (of the gun and cable assembly) in
your right hand and hold the shield with your left
hand. (Left handers simply do the opposite.)
FIGURE 17
When using the GMAW process on light gauge material, weld from right to left (if you are right handed).
This results in a colder weld and has less tendency for
burn through.
2. The Correct Way To Strike An Arc
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 Instruction Manual supplied
with welder.(ANSI Z.49.1-88)
-----------------------------------------------------------------------
1. Be sure the work clamp makes good electrical contact to the work.
2. Position gun over joint. End of wire may be lightly
touching the work.
3. Position face shield to protect face and eyes, close
gun trigger, and begin welding. Hold the gun so
that the contact tip to work distance is about 3/8 to
1/2 inch (10 – 12 mm).
4. To stop welding, release the gun trigger and 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, the ball may be
removed by feeding out a few inches of wire and
cutting off the end of the wire with wire cutters.
6. When no more welding is to be done, close the
valve on the gas cylinder, momentarily operate the
gun trigger to release gas pressure, then turn off
the machine.
WARNING
15°-20°
Push
10
LEARNING TO WELD
10
3. The 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 18.
Once the arc has been established, maintaining
the correct CTWD becomes extremely important.
The CTWD should be approximately 3/8 to 1/2 inch
(10 to 12 mm) long.
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 and/or fuse the wire to the contact
tip.
FIGURE 18
4. The Correct Welding Speed
The important thing to watch while welding is the
puddle of molten metal right behind the arc. See
Figure 19. 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.
Most beginners tend to weld too fast, resulting in a
thin, uneven, “wormy” looking bead. They are not
watching the molten metal.
FIGURE 19
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 or else
burn through, 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 15.
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 Contact Tip to Work Distance.
4. Correct welding speed is to perform the following
exercise. Refer to Figure 16. Use PROCESS
GUIDELINES in the Instruction Manual and
Application Guide on the inside of wire feed section
door for selection of welding wire, shielding gas,
wire feed speed, voltage, and for range of metal
thicknesses that can be welded.
1. Position face shield to protect face and eyes.
2. Learn to strike an arc by positioning the gun over
the joint and touching the wire to the work.
3. Press 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.
Contact Tip
Wire Electrode
CTWD
Molten puddle
Base metal
Push Technique
Weld metal ridge
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