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Table of Contents
Introduction to Welding .......................................................................................5
Glossary of Welding Terms...................................................................................6
Safety Precautions...............................................................................................9
Basic Setup.........................................................................................................10
Stick Setup...................................................................................................10
Lift TIG Setup...............................................................................................12
Starting with the Basics......................................................................................14
The Arc................................................................................................................15
Rate of Travel......................................................................................................16
Types of Welds and Joints....................................................................................17
Stick Process...............................................................................................21
TIG Process.................................................................................................22
2

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3

Thermal Arc Presents Basic Techniques in Welding
Thermal Arc presents a helpful reference guide for beginning and intermediate
welders. This guide was written to educate you on the basics of welding, including
welding terminology, basic setup, safety precautions, Stick and TIG welding techniques,
and types of welds and joints. This guide is not meant to replace training nor to
serve as a safety guide.
I. Introduction to Welding
Thermal Arc thanks you for your interest in this guide, and we’re thrilled you’ve chosen
to further your interest in the world of welding. While welding may not be your area of
expertise, we’d like to help you learn some basics. The information in this guide is an
excellent reference to help you tackle several projects from those around your home and
garage, to light fabrication, and maintenance / repair applications.
4

Glossary of Terms
Alloy
A mixture with metallic properties composed of two or more elements, of which at least
one is a metal.
Amperage
Amperage is a measure of how much electricity is flowing through your electrode, also
referred to as current.
Arc
The arc is the physical gap between the end of the electrode and the base of the metal while
current is passing through.
Bead
A bead is the completed weld joint on the work surface produced when the electrode or wire
is fused into the base metal.
Collet
The piece inside the torch body that holds the tungsten electrode in the TIG torch.
Consumable
Consumable refers to an electrode, or component that is consumed or used during the welding
process, such as an electrode coated in flux.
Current
Current is the flow of electricity through an electric circuit. Current is measured by amperage.
Duty Cycle
The Duty Cycle is the length of time a welding machine can operate during a ten-minute
interval at a given amperage.
Electrode
Also called a welding rod, is a filler metal in the form of wire or rod, through which current
is conducted between the electrode holder and the welding arc.
5

Electrode Holder
A device that holds the electrode (welding rod) and conducts electricity through the rod.
Filler Metal
Filler Metal is the material added to the weld pool typically to strengthen the weld joint.
Flux
A cleaning agent used to dissolve oxides, release trapped gases and slag, and to cleanse metals
for welding, soldering, and brazing.
Joint
A joint is the intersection where two pieces of metal meet. There are many different types
of welding joints.
Lift Arc
Lift-Arc is a method of starting the arc during TIG welding. As the tungsten is lifted from
the base metal, the arc is established.
Polarity
Electrical current has a negative and positive pole, thus giving it polarity. AC (Alternating
Current) and DC (Direct Current) are types of electrical current.
AC current reverses its direction in regular intervals, whereas DC current flows in one direction.
Power Source
The power source is the primary component of your welding system. It is your source of
electrical power, and can provide adjustable current and/or voltage.
Shielding Gas
Protective gas used to prevent atmospheric contamination of the weld pool.
Slag
The hardened protective coating over the weld, produced when the flux on a welding rod
melts while welding. Slag should be scraped / chipped from the weld and cleaned with
a metal wire brush.
Spatter
Spatter is small droplets of filler metal that have blown out onto the work surface by the arc.
6

Spot Weld
A process in which two metal surfaces are joined by the heat from resistance to electric
current flow, typically a very small weld size.
Steel
A type of metal that is made from mined iron ore, purified in blast furnaces, and then carbon
is added during its molten stage.
Stick Welding (SMAW, Shielded Metal Arc Welding)
Stick welding uses a consumable electrode that is coated in flux to create the weld. An electric
arc forms between the electrode and the base metal. As you weld, the flux coating melts from
the electrode (which creates vapors that act as the shielding gas) and leaves behind a layer of
slag that protects the weld from contamination.
Stinger
Stinger is another name for the electrode holder. You’ll typically hear it used in the shop
or field.
Tack Weld
A tack weld refers to a small weld that is used to hold what you’re welding in its place.
Tack welds can be broken if changes need to be made.
Tensile Strength
Tensile strength is an indication of a material’s ability to resist being pulled apart by tension.
TIG Welding (GTAW, Gas Tungsten Arc Welding)
TIG welding utilizes a non-consumable tungsten electrode, and in certain cases a separate
filler metal. Current flows through the TIG Torch and electrode, while an inert gas passes
through the torch. The arc is created between the base metal and the tungsten electrode.
The welding arc is shielded with an inert gas such as Argon.
Weld Pool
Also known as the weld puddle, the weld pool is the molten material produced while the arc
is created, and during the welding process. It is important to protect the weld pool from
contaminants while it solidifies.
Wire Brush
An important tool for cleaning the welding surface both before and after welding.
Voltage
Voltage is the force that makes electrons flow through the conductor.
7

Safety Precautions
It’s always important to be familiar with the welding equipment you’re using. Be sure to
read the operator’s manual for safety precautions specific to your equipment.
Electrical Shock
There’s always the threat of electrical shock when you’re welding, so taking proper
measures to prevent this is a must every time you gear up to weld.
• Never stand in water. Stand on a rubber mat or a dry area when welding.
• Make sure your welding equipment doesn’t make contact with water.
• Keep your clothes dry. This includes gloves, shoes, your shirt and pants, etc.
Perspiration can make you more vulnerable to electrical shock.
The Welding Environment
The heat produced while welding is capable of igniting flammable materials.
Be sure not to weld in areas containing flammable gases, vapors, or liquids.
Proper Safety Attire
As standard practice, you should always wear the proper clothing and safety equipment
when welding. This includes, but is not limited to:
• Eye protection • Welding helmet • Long sleeve shirts
• Leather gloves • Pants that cover your legs • Close-toed shoes
8

II. Basic Setup
Get to know your welding power source before you hook up anything. You should see
a negative output terminal, a positive output terminal, and a knob that adjusts your
welding current.
To set up for Stick Welding
1. With the power source off and unplugged, connect the ground clamp cable to the
negative output terminal, and the electrode holder cable to the positive output terminal.
2. Connect the ground clamp to your work piece.
3. Making sure the electrode holder is not touching the work piece, plug the power
cable into the appropriate outlet, and turn the power source on.
4. Make sure the process selection switch is set to STICK.
5. Set the weld current control knob to the desired amperage.
6. Install a stick electrode in the electrode holder.
7. You are now ready to begin Stick welding.
9

Stick (SMAW) Setup
Set Process Selection
Switch to Stick.
Negative Output
Terminal
(Dinse 25)
10
200A
Set Welding Current
as specied by the
Electrode Manufacturer.
Positive Output
Terminal
(Dinse 25)
Art #: A-08602

To set up for TIG Welding
1. With the power source off and unplugged, connect the ground clamp to the positive
output terminal, and the TIG torch cable to the negative output terminal.
2. Using a secured Argon cylinder, slowly crack open and then close the cylinder valve
while standing off to the side. This will remove any debris that may be around the
valve and regulator seat area.
3. Install the regulator on the Argon cylinder and tighten with a wrench.
4. Connect the gas hose to the outlet of the Argon regulator, and tighten
with a wrench.
5. Be sure the gas valve on the torch is closed, and slowly open the Argon Cylinder
Valve to the fully open position and adjust the flow to approx 20 cfh.
6. Connect the ground clamp to your work piece.
7. Making sure the electrode holder is not touching the work piece, plug the power
cable into the appropriate outlet, and turn the switch to the “ON” position.
8. Make sure the process selection switch is set to LIFT TIG.
9. Set the weld current control knob to the desired amperage.
10. The tungsten must be ground to a blunt point in order to achieve optimum welding
results. It is critical to grind the tungsten electrode in the direction the grinding
wheel is turning.
11. Install the tungsten with approximately 1/8” to ¼” sticking out from the gas cap,
ensuring you have the correct sized collet.
12. Tighten the back cap.
13. You are now ready to begin TIG welding.
11

Lift TIG (GTAW) Setup
12

III. Starting with the Basics
Basic Welding Techniques
Relaxation is Important
Place yourself in a comfortable position before beginning to weld. Utilize a seat with
the appropriate height and do as much work as possible sitting down. Don’t hold your
body tense. A taut attitude of mind and a tensed body will soon make you feel tired.
Relax and you will find that the job becomes much easier. Proper safety equipment will
keep you from being burned or sparks burning your clothes.
Establishing an Electrical Circuit
It’s important to establish an electrical circuit between the power source and the base
metal. So make sure that the work clamp is making good electrical contact with the
work piece, either directly or through the work table. For light gauge material, always
clamp the work lead directly to the job, otherwise a poor circuit could result.
Practice with Scrap
The simplest way to practice welding is to run beads on a piece of scrap plate. Clean
any paint, loose scale or grease off the plate and set it firmly on a solid surface like a
work bench so that you can practice.
The Line of Your Weld
Position the scrap piece so you can pull the weld across your body, rather than to and
from your body. The electrode holder lead should be clear of any obstruction so that
you can move your arm freely along as the electrode burns down. If the electrode cable
is slung over your shoulder, it allows greater freedom of movement and takes a lot of
weight off your hand. Be sure the insulation on your cable and electrode holder has no
damage; otherwise you are risking electrical shock.
STICK (SMAW) Electrode Polarity
Stick electrode leads are generally connected to the “+” Positive Output Terminal and
the work lead to the “−” Negative Output Terminal but if in doubt consult the electrode
manufacturers literature for specific information.
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Types of STICK (SMAW) Electrodes
Arc Welding electrodes are classified into a number of groups depending on their
applications. There are a great number of electrodes used for specialized industrial
purposes which are not of particular interest for everyday general work. These include
some low hydrogen types for high tensile steel, cellulose types for welding large
diameter pipes, etc. The range of electrodes dealt with in this publication will cover
the vast majority of applications likely to be encountered.
The ARC
Striking the Arc
Before welding, practice striking the arc on a piece of scrap plate. To strike an arc,
scratch the electrode along the plate’s surface in the same way a match is struck.
As soon as the arc is established, maintain a 1/16” to 1/8” gap between the burning
electrode and the base metal. Move the electrode slowly along your joint. A good weld
will look like a line of coins layered along one another.
Problems with Striking
You may at first experience difficulty due to the electrode “sticking” to the work piece.
This is caused by making contact with the work piece too heavily and failing to withdraw
the electrode quickly enough. Low amperage settings on your power source can
accentuate this problem.
14

Establishing the Arc Length
Establishing a good arc length is necessary to produce a quality weld. After striking,
maintain a 1/16” to 1/8” gap between the burning electrode and the work piece.
A good arc will produce a crackling noise.
Problems with Arc Length
A common problem after the arc is established is the tendency to pull the electrode
so far away from the weld piece that the arc breaks.
A little practice and persistence and you’ll develop a feel for the correct length
of your arc.
Striking the Arc
Rate of Travel
Direction of Travel
After the arc is struck, your next concern is to maintain it, and this requires moving
the electrode towards the molten pool at the same rate as it is melting away. At the
same time, the electrode has to move along the plate to form a bead. The electrode is
directed at the weld pool at about 20 degrees from the vertical. The rate of travel has
to be adjusted so that a well-formed bead is produced. If the travel is too fast, the
bead will be narrow and strung out and may even be broken up into individual globules.
If the travel is too slow, the weld metal piles up and the bead will be too large.
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IV. Types of Welds and Joints
Making Welded Joints
Convinced you can now weld like a pro? Well let’s not get ahead of ourselves. After
practicing on scrap plates it’s time to move to welded joints. Having attained some
skill in the handling of an electrode, you will be ready to create welded joints. Remember
though, in many cases it will be possible to weld steel sections without any special
preparation. However, for heavier sections and for repair work on castings, etc., it may
be necessary to cut or grind an angle or a bevel, between the pieces being joined to
ensure proper penetration of the weld metal and to produce sound joints. In general,
surfaces being welded should be clean and free of rust, scale, dirt, grease, etc. Slag
should be removed from oxy-cut surfaces.
Types of Welds & Joints
A. Butt Weld Joints
Set up two plates with their edges parallel, allowing 1/16” to 3/32” gap between them
and tack weld at both ends. This is to prevent weld metal from pulling the plates out of
alignment. Do not weave the electrode, but maintain a steady rate of travel along the
joint sufficient to produce a well-formed bead. At first you may notice a tendency for
undercut to form, but keeping the arc length short, the angle of the electrode needs to
be moved along fast enough to prevent the slag pool from getting ahead of the arc.
Heavy plate may require several passes to complete the joint, and perhaps a small
beveled edge. After completing the first pass, chip the slag out and clean the weld
with a wire brush. It is important to do this to prevent slag being trapped by the
second pass. Subsequent passes are then deposited using either a weave technique or
single stringer beads. The width of weave should not be more than three times the core
wire diameter of the electrode. When the joint is completely filled, the back can
be machined, ground or gouged out to remove slag which may be trapped in the
root, and to prepare a suitable joint for welding the back section.
16

Typical Butt Weld Joint
B. Fillet Weld Joints
These typically are welds that join two sections meeting at right angles. Tack together a
piece of angle iron, or two lengths of strip steel at right angles to begin. Strike the arc
and immediately bring the electrode to a position perpendicular to the line of the fillet
and about 45 degrees from vertical. Some electrodes require to be sloped about 20
degrees away from the perpendicular position to prevent slag from running ahead of the
weld. Do not attempt to build up too much weld metal as it tends to sag, and undercut
can form on the vertical leg.
Typical Fillet Weld Joint
17

C. Vertical Welds
Tack weld a section of angle iron to your work bench in an upright position. Make
yourself comfortable on a seat and strike the arc in the corner of the fillet. The
electrode needs to be about 10 degrees from the horizontal to enable a good bead to
be deposited. Use a short arc, and do not attempt to weave on the first pass. When
the first pass has been completed chip the slag from the weld, wire bush it, and begin
the second pass. This time a slight weaving motion may be necessary to cover the
first pass and obtain good fusion at the edges. At the completion of each side motion,
pause for a moment to allow weld metal to build up at the edges, otherwise undercut
can form and too much metal will accumulate in the center of the weld.
Typical Vertical Fillet Weld
18

Overhead Welds
Apart from the rather awkward position, overhead welding is not that difficult. Set
up a test piece for overhead welding by first tacking two pieces together forming right
angles. Then tack this to the work bench or hold in a vice so that it is in the overhead
position. The electrode is held at approximately 45 degrees to the horizontal and tilted
10 degrees in the line of travel. The electrode may lightly touch the metal, which helps
it remain steady. A weave technique is not advisable for overhead fillet welds.
Typical Overhead Weld Example
19

Additional Weld Joint Types
Open Square Butt
Joint
Gap varies from
1/16” (1.6mm) to 3/16” (4.8mm)
depending on plate thickness
Single Vee Butt Joint
Lap Joint
Fillet Joint
Corner Weld
Plug Weld
Not less than
45°
Single Vee Butt Joint
Double Vee Butt Joint
Tee Joints
(Fillet both sides of the
joint)
20
Edge Joint
Plug Weld
1.6mm (1/16”)
1/16” (1.6mm)
Not less than
70°
Not less than
70°
1/16” (1.6mm) max
1/16” (1.6mm) max

Effects of Stick Welding Various Materials
High Tensile and Alloy Steels
The two most prominent effects of welding these steels are the formation of a hardened
zone in the weld area, and, if suitable precautions are not taken, the occurrence in this
zone of under-bead cracks. Hardened zone and under-bead cracks in the weld area may
be reduced by using the correct electrodes, preheating, using higher current settings, or
using larger electrodes sizes.
Manganese Steels
The effect on manganese steel of slow cooling from high temperatures is to embrittle it.
For this reason it is absolutely essential to keep manganese steel cool during welding by
quenching after each weld or skip welding to distribute the heat.
Cast Iron
Most types of cast iron, except white iron, are weldable. White iron, because of its
extreme brittleness, generally cracks when attempts are made to weld it. Trouble may
also be experienced when welding white-heart malleable, due to the porosity caused by
gas held in this type of iron.
Copper and Alloys
The most important factor is the high rate of heat conductivity of copper, making
pre-heating of heavy sections necessary to give proper fusion of weld and base metal.
TIG (Gas Tungsten Arc Welding, GTAW)
TIG (GTAW) Electrode Polarity
Connect the TIG torch to the “-” Negative Output Terminal and the work lead to the
“+” Positive Output Terminal for direct current straight polarity. Direct current straight
polarity is the most widely used polarity for DC TIG welding. It allows limited wear of the
electrode since 70% of the heat is concentrated at the work piece.
21

Tungsten Preparation & Sharpening
For DC TIG welding, it is ideal to sharpen the tungsten electrode to a blunt point. This
will help concentrate the welding arc as you complete the joint. Be sure to hold the
tungsten in line with the direction the grinding wheel is turning. This will ensure the
“grind marks” are running in line with the tungsten to help direct the current to the
work piece.
Basic Tungsten Electrode Types
TIG Welding Direction of Travel and Torch Position
Direction of travel should progress away from the section being welded. Torch angle
should be that so the filler rod and torch form approximately a 90 degree angle.
The torch should also be angled slightly towards the direction you are traveling.
22

TIG Welding Parameters
Tungsten Electrode Current Ranges
Shielding Gas Selection
Typical shielding gas flow rates can range between 10-25 cubic feet per hour (cfh).
Filler Rods
Filler rods ranging in various sizes may be used to “dip” into the weld pool to strengthen
the weld joint. Most come in 36” cut lengths, and different alloys. Be sure to choose
the appropriate alloy for your application.
23