WIA MC105-0 User manual

MC105-40 Rev A
Weldarc 200i AC/DC
Weldarc 200i AC/DC Arc/TIG Welder
Model No. MC105-0
Iss A
Operators Manual
02/16

Welding Industries of Australia
A division of ITW Australia Pty Ltd
1300 300 884
[email protected]
welding.com.au

Weldmatic 200i AC/DC
Model No MC105, Iss A 02/16 1
Contents
Section General Information Page
Safe Practices 2
1 Introduction 5
2 Receiving 6
3 Operation 6
4 Specifications 7
5 Controls 9
6 Installation 14
7 Basic Welding Information 15
8 External Trouble Shooting 19
9 Service Information 20
9.1 Circuit Diagram 21
10 Assembly and Parts Lists
Power Source 22
11 Warranty Information 26

Operators Manual
2 Trusted by the best
Read First
The information contained in this
manual is set out to enable you
to properly maintain your new
equipment and ensure that you obtain
maximum operating efficiency.
Please ensure that this information is
kept in a safe place for ready reference
when required at any future time.
When ordering spare parts, please
quote the model and serial number
of the power source and part number
of the item required. All relevant
numbers are shown in lists contained
in this manual. Failure to supply this
information may result in unnecessary
delays in supplying the correct parts.
Safety
Before this equipment is put into
operation, please read the Safe
Practices section of this manual.
This will help to avoid possible injury
due to misuse or improper welding
applications.
Plastic Handles on Power
Source
Please note that the handle fitted to
the Weldarc 200i inverter is intended
for carrying the equipment by hand
only.
DO NOT use this handle for
suspending or mounting the Weldarc
in any other manner.
Safe Practices When Using
Welding Equipment
These notes are provided in the interests
of improving operator safety. They should
be considered only as a basic guide to Safe
Working Habits. A full list of Standards
pertaining to industry is available from
the Standards Association of Australia,
also various State Electricity Authorities,
Departments of Labour and Industry or
Mines Department and other Local Health
or Safety Inspection Authorities may have
additional requirements. Australian Standard
AS1674.2 provides a comprehensive guide to
safe practices in welding.
Eye Protection
NEVER LOOK AT AN ARC WITHOUT
PROTECTION. Wear a helmet with
safety goggles or glasses with side shields
underneath, with appropriate filter lenses
protected by clear cover lens. This is a MUST
for welding, cutting, and chipping to protect
the eyes from radiant energy and flying
metal. Replace the cover lens when broken,
pitted, or spattered.
Recommended Shade Filter Lens
Amps TIG MMAW MIG
Pulsed
MIG
0-100 10 9 10 12-13
100-150 11 10 10 12-13
150-200 12 10-11 11-12 12-13
200-300 13 11 12-13 12-13
300-400 14 12 13 14
400-500 — 13 14 14
500 + — — 14 14

Weldmatic 200i AC/DC
Model No MC105, Iss A 02/16 3
Burn Protection
The welding arc is intense and visibly bright.
Its radiation can damage eyes, penetrate
light-weight clothing, reflect from light-
coloured surfaces, and burn the skin and
eyes. Burns resulting from gas-shielded arcs
resemble acute sunburn, but can be more
severe and painful.
Wear protective clothing – leather or heat
resistant gloves, hat, and safety-toed boots.
Button shirt collar and pocket flaps, and
wear cuffless trousers to avoid entry of
sparks and slag.
Avoid oily or greasy clothing. A spark may
ignite them. Hot metal such as electrode
stubs and work pieces should never be
handled without gloves.
Ear plugs should be worn when welding in
overhead positions or in a confined space.
A hard hat should be worn when others are
working overhead.
Flammable hair preparations should not be
used by persons intending to weld or cut.
Toxic Fumes
Adequate ventilation with air is essential.
Severe discomfort, illness or death can
result from fumes, vapours, heat, or oxygen
depletion that welding or cutting may
produce. NEVER ventilate with oxygen.
Lead, cadmium, zinc, mercury, and beryllium
bearing and similar materials when welded
or cut may produce harmful concentrations
of toxic fumes. Adequate local exhaust
ventilation must be used, or each person in
the area as well as the operator must wear
an air-supplied respirator. For beryllium, both
must be used.
Metals coated with or containing materials
that emit fumes should not be heated unless
coating is removed from the work surface,
the area is well ventilated, or the operator
wears an air-supplied respirator.
Work in a confined space only while it is
being ventilated and, if necessary, while
wearing air-supplied respirator.
Vapours from chlorinated solvents can be
decomposed by the heat of the arc (or
flame) to form phosgene, a highly toxic
gas, and lung and eye irritating products.
The ultra-violet (radiant) energy of the arc
can also decompose trichlorethylene and
perchlorethylene vapours to form phosgene.
Do not weld or cut where solvent vapours
can be drawn into the welding or cutting
atmosphere or where the radiant energy
can penetrate to atmospheres containing
even minute amounts of trichlorethylene or
percholorethylene.
Fire And Explosion Prevention
Be aware that flying sparks or falling slag can
pass through cracks, along pipes, through
windows or doors, and through wall or floor
openings, out of sight of the operator. Sparks
and slag can travel up to 10 metres from the arc.
Keep equipment clean and operable, free of
oil, grease, and (in electrical parts) of metallic
particles that can cause short circuits.
If combustibles are present in the work
area, do NOT weld or cut. Move the work if
practicable, to an area free of combustibles.
Avoid paint spray rooms, dip tanks, storage
areas, ventilators. If the work can not be
moved, move combustibles at least 10 metres
away out of reach of sparks and heat; or
protect against ignition with suitable and
snug-fitting fire-resistant covers or shields.
Walls touching combustibles on opposite
sides should not be welded on or cut. Walls,
ceilings, and floor near work should be
protected by heat-resistant covers or shields.

Operators Manual
4 Trusted by the best
A person acting as Fire Watcher must be
standing by with suitable fire extinguishing
equipment during and for some time after
welding or cutting if;
• Combustibles (including building
construction) are within 10 metres.
• Combustibles are further than 10 metres
but can be ignited by sparks.
• Openings (concealed or visible) in floors
or walls within 10 metres may expose
combustibles to sparks.
• Combustibles adjacent to walls, ceilings,
roofs, or metal partitions can be ignited
by radiant or conducted heat.
After work is done, check that area is free of
sparks, glowing embers, and flames.
A tank or drum which has contained
combustibles can produce flammable
vapours when heated. Such a container must
never be welded on or cut, unless it has first
been cleaned as described in AS.1674-2.
This includes a thorough steam or caustic
cleaning (or a solvent or water washing,
depending on the combustible’s solubility),
followed by purging and inerting with nitrogen
or carbon dioxide, and using protective
equipment as recommended in AS.1674-2.
Water-filling just below working level may
substitute for inerting.
Hollow castings or containers must be vented
before welding or cutting. They can explode.
Never weld or cut where the air may contain
flammable dust, gas, or liquid vapours.
Shock Prevention
Exposed conductors or other bare metal
in the welding circuit, or ungrounded
electrically alive equipment can fatally shock
a person whose body becomes a conductor.
Ensure that the equipment is correctly
connected and earthed. If unsure have the
equipment installed by a qualified electrician.
On mobile or portable equipment, regularly
inspect condition of trailing power leads
and connecting plugs. Repair or replace
damaged leads.
Fully insulated electrode holders should be
used. Do not use holders with protruding
screws. Fully insulated lock-type connectors
should be used to join welding cable lengths.
Terminals and other exposed parts of
electrical units should have insulated knobs
or covers secured before operation.

Weldmatic 200i AC/DC
Model No MC105, Iss A 02/16 5
1 Introduction
MMAW (Stick Welding)
Manual Metal Arc Welding (MMAW) is a
process where an arc is struck between a
flux-coated consumable electrode and the
work piece. The arc and the weld pool are
both shielded by gases generated by the flux
coating of the electrode.
The Weldarc 200i has been designed to
be used with 2.0mm, 2.5mm, 3.2mm and
4.0mm diameter electrodes. The smaller
electrodes are used when welding at lower
currents, such as sheet metal applications.
Increasing the electrode diameter permits
higher welding currents to be selected.
WIA supplies a wide range of mild steel and
special purpose electrodes which cater for home
workshop, rural, and industrial requirements.
Some popular AUSTARC electrodes are listed
below. The correctly selected AUSTARC
electrode will influence the quality of the weld,
and the stability of the arc.
Austarc 12P, Classification E4313-A
A popular general purpose electrode
used with ease in all positions, vertical up
or down. The smooth forceful arc makes
it an ideal electrode for all general mild
steel applications.
Austarc 13S, Classification E4313-A
A smooth running electrode with a soft arc,
particularly suited to light sheetmetal and
smooth mitre fillet welds.
Austarc 16TC, Classification E4916-A
A low hydrogen electrode with good
arc stability and out-of-position welding
characteristics. This electrode is ideal
for medium carbon steels, or steels of
unknown analysis.
Austarc 11, Classification E4311-A
A high cellulose electrode for all positional
welding, AC or DC. Particularly suited for
vertical and incline pipe welding where
complete root penetration is required.
Unicord 312, Classification ES312-16
A high tensile (50tsi), chromium nickel
electrode specially formulated for joining
all alloy steels and irons, and for tool and
die maintenance.
GTAW (TIG Welding)
Gas Tungsten Arc Welding (GTAW) is a
welding process where the arc is struck
between a non-consumable tungsten
electrode and the work piece. A ceramic
nozzle surrounds the tungsten electrode and
directs a flow of inert gas, usually Argon,
over the electrode and the weld zone. If
filler metal is required, it is hand fed into
the welding arc. The DC current output of
the Weldarc inverter is suitable for welding
most ferrous and non-ferrous metals. The AC
current output is for welding Aluminium.

Operators Manual
6 Trusted by the best
If the supply cable is damaged it
must be replaced by the manufacturer,
their service agent or a similarly
qualified person.
IMPORTANT NOTICE: Warranty may
be voided if equipment is powered
from an unsuitable engine driven
generator.
Generators used to power this equipment
must have a minimum capacity of 10 kW
continuous and incorporate output
voltage regulation.
Due to variation between generators by
different manufacturers, it is impossible
for WIA to validate operation from all
generators. Therefore, we recommend
that operation of equipment on
the generator is received from the
manufacturer before purchasing the
generator.
2 Receiving
Check the equipment received against the
shipping invoice to make sure the shipment
is complete and undamaged. If any damage
has occurred in transit, please immediately
notify your supplier.
The Weldarc inverter package contains;
• Weldarc Inverter Power Source
• Twist-lock Electrode Holder
• Work Clamp 3m
• (This) Operating Manual MC105-40.
• TIG Torch Complete WP17V121625
with valve, 5m cable with twist-lock
connection and fitted with 2.4mm collet
and ceriated tungsten
• TIG Consumable KIT
• Argon flow gauge regulator REG003
3 Operation
VRD Function - Only active during
MMA
Whenever the welding output of the Weldarc
inverter is open circuit (ie not arcing), the
voltage across the welding leads is reduced
to a safe level. This provides an increased
level of safety to the welding operator during
operations such as changing the electrode.
The “VRD SAFE” indicator on the front
panel is on to confirm the output is in the
safe condition.
The term VRD refers to a “Voltage Reducing
Device”which complies with AS1674.2 for
Category “C” conditions.

Weldmatic 200i AC/DC
Model No MC105, Iss A 02/16 7
4 Specifications
Manufactured to Australian Standard
IEC60974-10 6.3.2 6.3.3.
TERM VALUE UNIT
Rated Input Voltage 220 - 240 V
Power Frequency 50/60 Hz
Rated Input Capacity 7.9 KVA
Generator Capacity 10 KVA
Rated Maximum Supply Current Imax 34 A
Maximum Effective Supply Current Ieff 13 A
Output No Load Voltage 71 V
Supply Main Circuit Breaker 25 A
Supply Cable 2.5mm2 & Plug Rating 15 A
Extension Lead Rating 15 A
VRD Safe 13.5 V
Rated Output 240 ° C
Stick MMA 170 Amps @26.8 Volts 15% Duty
Stick MMA 66 Amps @22.6 Volts 100% Duty
TIG 200 Amps 18 Volts 15% Duty
TIG 77 Amps 13.1 Volts 100% Duty
Current Up Slope Time 0 ~ 15 S
Current Down slope Time 0 ~ 25 S
Pulse Frequency 0.5 ~ 200 Hz
Pulse Width Adjustment (DC) 15 ~ 85 %
AC Balance Control, Negative 15 ~ 65 %
Arc Force Control MMA 0 -100 %
Arc Start MMA 0 - 70 A
Arc Start MMA 0.2 S
Post Gas Time 0 ~ 30 S
Pre Gas Time 0 ~ 5 S
Cooling Type Fan on Demand
Efficiency ≥85% n
Power Factor 0.92 Cos§

Operators Manual
8 Trusted by the best
Insulation Degree H
Cover Protection Degree IP21S IP
Weight 19.5 kg
Shipping Weight 25 kg
Dimension L × W × H 530 x 240 x 420 mm
Shipping Dimension L × W × H 770 x 335 x 460 mm
4 Specifications (cont)

6/11/15
200i AC/DC
WIN567B 200i AC/DC (PREVIEW) B
HOT
STA R T
IGNITION
CURRENT
UP
SLOPE
WELDING
CURRENT
PEAK
CURRENT
HERTZ
BASE
CURRENT
DOWN
SLOPE
CRATER
CURRENT
PULSE
RATIO
PRESS
GAS PURGE
AMPS
HF
PULSE
AC/DC
MODE GAS
WIN567B
Welding Industries of Australia
welding.com.au
Weldmatic 200i AC/DC
Model No MC105, Iss A 02/16 9
Fig 1 Weldarc 200i AC/DC Controls
5 Controls
13 14 Power Switch
Located on the rear panel
11
1
12
1 VRD Safe Mode Indicator
When the machine is in MMA stick mode
the light will be on when the voltage across
the output terminals is reduced to safe level.
The VRD will operate in accordance the
requirements of AS1672.2 2007 Category C
Environment.
3
2
4
5
66 78
10
9
2 Over Temperature Indicator
This light will come on if any internal thermal
protection devices have operated due to
overheating, caused by the duty cycle
being exceeded.
The machine will not weld but the fan will
continue to operate to cool the machine.
When a safe temperature has been reached,
the thermal protection device will reset and
welding can continue.

Operators Manual
10 Trusted by the best
3 Voltage Range Indicator
This light will be on when the input supply
voltage is too high or too low. There will be
no output.
Low voltage can occur on a weak power
supply, or if the machine is operated from a
long power cable from a weak supply, or an
under rated generator.
High voltage can occur on some rural power
supplies and lightly loaded generators.
4 Latch Mode 2T/4T
Latch mode provides a 2 STEP or 4 STEP
trigger control while in TIG mode:
4.1 2 STEP
In this mode the torch trigger must be
pressed on to initiate welding and held
on till welding is finished.
Up slope and down slope, ignition
current and crater current cannot
used in the 2 STEP.
4.2 4 STEP
In this mode the torch trigger switch is
pressed to start the arc.
The current will stay at the ARC IGNITION
setting.
When trigger is released the current
will increase to the WELDING CURRENT
setting, according to the UP SLOPE time.
Output will continue at WELDING
CURRENT setting.
When torch trigger is pressed again then
the weld output will decrease down to
CRATER CURRENT setting, according to the
DOWN SLOPE time.
Weld output will remain at CRATER
CURRENT until torch trigger is released,
then gas will flow for POST GAS time.
Fig 3 Latch Mode–4 STEP
Time
Amps
IGNITION
CURRENT
PRE GASPOST GAS
UP SLOPE
WELDING CURRENT
DOWN SLOPECRATER
CURRENT
Press +Hold
Torch Trigger
Press +Hold
Torch Trigger
Release
Torch Trigger
Release
Torch Trigger
Fig 2 Latch Mode–2 STEP
Time
Amps
PRE GASPOST GAS
WELDING CURRENT
Press +Hold
Torch Trigger
Release
Torch Trigger
5 Controls

Weldmatic 200i AC/DC
Model No MC105, Iss A 02/16 11
5 Gas Purge
Press and hold the gas purge button to allow
gas to flow without output weld voltage or
current. This feature can be used when a gas
bottle is connected and air can be purged
from the gas line and torch. It can also be
used to safely set shielding gas flow rate
at the gas flowmeter, without the welding
current outputs being live.
6 Parameter Select
Use these buttons to cycle through the
Welding parameters, which can then be
adjusted by knob 7. If no adjustment is made
after 4 seconds the parameter will change
back to WELDING CURRENT.
7 Adjustment Knob
This knob is used to adjust the parameter of
the weld function, as selected by button 6.
8 Weld Mode Selection
The Weld Mode can select between the three
mode of operation.
8.1 Stick MMA Mode
In this mode the machine performs as
a DC stick MMA welding machine. The
HOT START and ARC FORCE parameters
can be adjusted on the front panel.
8.2 Lift Arc TIG
In this mode the machine will perform as
a AC or DC TIG machine. The arc start is
by Lift Arc technique.
8.3 High Frequency Start TIG
In this mode the machine will perform as
AC or DC machine with High Frequency
(HF) arc start. When the tungsten is near
the work piece and the torch trigger
is pressed, then a high energy spark is
created to jump from the tungsten to
work piece and initiate an Arc.
9 Pulse Mode
When in LIFT-ARC TIG or HF TIG mode, then
Pulse TIG can be selected and the parameters
for adjusting the pulse shape will be available
for adjustment.
Peak Current, Pulse Ratio, Frequency Hertz,
and Base Current.
10 AC/DC Mode
The polarity of the output current can be
selected between Alternating Current (AC)
or Direct Current (DC).
AC mode can only be selected in TIG mode.
The alternating current arc can be used
specifically for welding aluminium.
11 AMPS Display
The Left hand digital display will show
Amps while adjusting current with knob 7,
and then display weld Amps while welding
is in progress.
12 Multi Parameter Display
The right hand display will show the value
of a parameter being adjusted. The type of
parameter will be indicated by one of the 4
indicators next to the display.
For example if the AC Frequency is being
adjusted then Hz indicator will be on and the
display will show the frequency that is being
adjusted by knob 7.

Operators Manual
12 Trusted by the best
13 Welding Parameters
13.1 Pre Gas
Pre gas flow can be set to a maximum
of 5 seconds, to allow gas flow before
Arc Start.
13.2 Hot Start
Only available in Stick MMA mode, Hot
Start will provide a current boost at the
start of the arc. The parameter can be
adjusted up to 70Amps which will add
to the preset welding current.
13.3 Ignition Current
While in 4 STEP latch mode the arc will
start and maintain the Ignition current
output until the trigger torch is released.
The IGNITION CURRENT can be more or
less than the WELD CURRENT setting.
Setting the IGNITION CURRENT high
can be useful for joint preheat.
13.4 Up Slope
The UP SLOPE time is the time taken
for the weld current to transition from
the IGNITION CURRENT value to WELD
CURRENT value. The time can be
adjusted from 0 to 15 seconds.
13.5 Welding Current
The setting for actual weld current.
13.6 Pulse Welding
Pulse welding allows the current to
be pulsed between two different
values, the frequency and ratio can be
adjusted. This feature can be used on
thin material.
13.6.1 Peak Current
Set the Peak current Amps.
13.6.2 Pulse Ratio
Set the ratio in % for the peak
current compared to the back
ground current. Range is 15%
to 85%.
13.6.3 Hertz
The frequency of the pulse can be
set, as number of pulses for second
(HERTZ) 0.5Hz to 200Hz.
13.6.4 Base Current
Set the Base current Amps.
HOT
STAR T
IGNITION
CURRENT
UP
SLOPE
WELDING
CURRENT
PEAK
CURRENT
HERTZ
BASE
CURRENT
DOWN
SLOPE
CRATER
CURRENT
PULSE
RATIO
Fig 4 Weldarc 200i AC/DC Welding Parameters
5 Controls

Weldmatic 200i AC/DC
Model No MC105, Iss A 02/16 13
13.6.5 Down Slope
The DOWN SLOPE time is the
time taken for the weld current
to transition from the WELDING
CURRENT value to CRATER
CURRENT value. The time can be
adjusted from 0 to 25 seconds.
13.6.6 Crater Current
The current at the end of WELD
can be adjusted to a value which
will allow controlled finish of the
weld. The end of weld pool (Crater)
can be filled.
13.6.7 Post Gas
The Post Gas time can be adjusted
to allow gas to flow after weld has
stopped. This feature can be used to
provide a gas shield to the cooling
weld pool. Adjustable from 0 to 30
seconds.
13.7 AC Frequency
When AC mode is selected by button
(10) then actual AC frequency can be
adjusted from 20 to 200Hz.
Increasing the frequency makes the
welding current change direction at a
faster rate. The arc becomes constricted,
more stable and directional, providing
deep penetrating narrow welds.
When the frequency is lower the arc is
wide with shallow penetration, suitable
for butt or edge welds on thin material.
13.8 AC Balance Or Arc Force
13.8.1 AC Balance
When AC TIG mode is selected
then the proportion of positive
and negative in the cycle can be
adjusted. This is referred to as the
BALANCE and is expressed as a
% of the time that the polarity
is negative. Adjustment is from
15% - 65%.
Arc Welding of aluminium is difficult
because the metal readily forms an
oxide layer, which is an electrical
insulator, and inhibits arc formation.
The Oxide needs to be “cleaned
off”. Electrode positive will remove
the oxide off the surface as the
electrons flow off the aluminium to
the tungsten electrode. Continuous
electrode positive will burn the
tip away, so the current has to be
reversed to electrode negative, for
some of the time.
For new clean aluminium an
AC BALANCE of 65% is a good
starting point.
++
%
−%
−
Fig 5 AC Balance

Operators Manual
14 Trusted by the best
13.8.1.1 Low % Balance
› Less time negative
› More time positive
› More cleaning action
› More heat in the tungsten
› Wider weld with shallower
penetration
13.8.1.2 High % Balance
› More time negative
› Less time positive
› Less cleaning action
› Less heat in the tungsten,
higher current for smaller
electrode
› Narrow weld beads with
deeper penetration
› Smaller heat affected zone
13.8.2 Arc Force
When machine is in Stick MMA
mode, selecting the ARC FORCE
allows adjustment of the % increase
in current that will occur when the
arc starts to short circuit, or snap out.
Adjusting this value can be useful
when using cellulose electrodes.
14 Power On/Off Switch
In the OFF position, this switch isolates the
power source from mains power supply.
The switch is located on the rear panel.
6 Installation
Connection to Electrical Mains Power
Supply
The Weldarc 200i AC/DC is fitted with a
15 Amp plug and socket, recognisable by
a wide Earth pin. Power Supply authorities
require that equipment fitted with a 15 Amp
plug shall ONLY be connected to a 240 Volt,
15 Amp power point. DO NOT modify
the plug.
The minimum capacity of the main power
supply wiring and power outlet supplying a
welder is selected according to the Effective
Primary Current of the equipment. Refer to
Section 4.
The minimum recommended main power
supply circuit breaker rating for Weldarc
inverter are listed in Section 4.
The current rating of the mains cable
depends on cable size and method of
installation. Refer to AS/NZS 3008.1, Table 9.
If it becomes necessary to replace the mains
flexible supply cable, use only cable with
correct current rating. See Section 4.
If it is necessary to use an extension power
supply cable, ensure that it is rated as per
Section 4. Voltage drop which will occur over
long lengths of cable will reduce the quality
of welds and the maximum welding current
available from the equipment.
As noted previously, it is not recommended
that the Weldarc inverter be powered from
small engine-driven generator sets unless
they have adequate voltage regulation. Poor
regulation results in peaks of supply voltage
which can occur with some equipment
of this type. Excessive voltage peaks can
damage the circuits of the welder.
5 Controls

Weldmatic 200i AC/DC
Model No MC105, Iss A 02/16 15
7 Basic Welding Information
Stick Welding (MMAW)
Connection for Stick Welding
It is important to select the electrode polarity
in accordance with the manufacturers
recommendations for that electrode. Most
common electrodes, including cellulose
types, are operated with the electrode at
positive polarity, as illustrated in Figure 6.
Stick Welding
Be certain that you are wearing suitable
protective clothing, gloves etc and that
you are working in a non-hazardous area.
If necessary, refer again to Section 1 - Safe
Practices in this manual.
Connect the work clamp to the work
piece. Place the desired electrode in the
electrode holder.
Turn on the power switch located on the rear
panel. Wait approximately 5 seconds as the
unit goes through its initiation sequence.
Use the Weld Mode Selection button to
select Stick Mode.
Select an appropriate welding current for
the electrode diameter by setting the knob
on the machine front panel. WIA AUSTARC
electrodes will give the best results.
Work
ClampElectrode
To strike the arc, drag the end of the
electrode along the work piece as if striking
a match. As the arc initiates, lift the electrode
slightly away, aiming to establish an arc
length of approximately 3mm.
As the electrode end is consumed, feed the
electrode into the arc in order to maintain
arc length. As a general rule, the arc should
be held as short as possible while still giving
stable burn off and good weld appearance.
An arc which is too long causes an unwieldy
flow of metal with a rough weld appearance
and reduced penetration. An arc too short
leads to a narrow weld deposit and “stuttery”
arc characteristics, and the electrode is liable
to freeze onto the work piece.
As the solidified weld deposit forms, move
the end of the electrode slowly along
the weld path, aiming to maintain a pool
of molten weld metal behind the arc.
Decreasing this rate of travel will result in a
wider weld deposit, and similarly increasing it
will narrow the weld deposit.
Always fill the crater which tends to form
at the end of a weld deposit, by pausing
momentarily before withdrawing the electrode
to break the arc. Unfilled craters are a point
of weakness, and can lead to weld cracking.
Current Range for General Purpose
Electrodes
Diameter (mm) Current (Amps)
2.0 40 -60
2.5 60 - 85
3.2 90 - 130
4.0 130 - 180
Fig 6 Connections for Stick Welding (MMAW)

Operators Manual
16 Trusted by the best
TIG Welding (GTAW)
Connection for TIG Welding
For TIG Welding, the TIG torch is connected
to the negative terminal. Figure 7 illustrates
the correct connection of the welding torch
and gas supply. Welding grade Argon is the
shielding gas most commonly used for AC/
DC GTAW welding. The torch will require a
tungsten electrode.
Before first use of the welding torch,
allow gas to purge the torch and hoses for
1 minutes at approximately 10 litres/min. For
welding purposes, the gas flow rate should
be set in the range 5-11 litres/min.
Fig 7 Connections for TIG Welding
Electrode TIG
Thoriated Tungsten electrodes are normally
used for DC welding current, and Zirconiated
Tungsten electrodes are normally used for AC
TIG welding.
For AC TIG welding a Thoritated tungsten
(red tip) can be used for low current AC TIG
but the tip does not ball well and the arc can
then wander.
Ceriated or Lanthinated are preferred for
advanced AC Welding with square wave
output. They can also be used on DC TIG,
so they are a good AC or DC electrode if
only one electrode type is to be used.
Tungsten Electrode Preperation
The tungstens needs to be ground to a point,
the grinding should only be in the direction
of the point and should be done on a fine
grit grinding wheel. The resulting grind
pattern will produce a sharp directed arc.
Poor tip preparation will result in arc wander.
A common practice is to grind the tip such
that the length of the points is approximately
2 times the diameter. The result will be an
included angle of 30 degrees.
For AC tip preparation, creating a blunt end
will assist a symmetrical and small ball to
develop at the tip.
It is important to maintain the electrode
point for DC or ball for AC. If the tip
accidently touches weld pool it will become
contaminated and the arc will become
erratic, and will need to be re ground.
Tungstens containing at least 2% lanthana
will hold a point when used with both DC
and AC welding currents
7 Basic Welding Information
TIG
Torch
Work
Clamp

Weldmatic 200i AC/DC
Model No MC105, Iss A 02/16 17
D
x
Fig 9 AC Advanced Preparation
x = 1.5 to 4 times diameter
Fig 10 Correct Grind Direction
Fig 11 Incorrect Grind Direction
D
30°
30° x
Fig 8 Tungsten Preparation
x = 1.5 to 4 times diameter
(2 x D = 30° included angle)
Tungsten Current Ranges
Electrode
Diameter (mm)
Gas
Cup Size
DC
Current Amps
AC
Current Amps
Filler Wire
Diameter (mm)
1.0 6 15-80 20-60 1.6
1.6 6 70-150 50-100 1.6-2.4
2.4 8 150-250 100-160 2.4-3.2
Safety Consideration Thoritated
Tungsten.
Thoriated Tungsten contains the element
Thorium (Th). Thorium is a radioactive
element which mainly emits alpha
particles. Alpha particles cannot penetrate
skin, or clothing, but can be a harmful
carcinogen if released inside the digestive
tract, or lungs.
There is almost no release of radioactive
material during arcing.
There is no significant hazard in handling
and storage. The Thoria is inside the
tungsten electrode, it is enclosed in a
tungsten matrix and so there is little
radiation emitted externally.
The greatest risk of exposure is during
the grinding of the thoriated tungsten
electrodes. Care needs to be taken, to
control the dust. A dust mask should be
worn, and grinder area clean up should
be done with a vacuum cleaner.

Operators Manual
18 Trusted by the best
TIG Welding Operation
Connect the Work Clamp to the work piece.
Turn on the power switch located on the rear
panel. Wait approximately 5 seconds as the
unit goes through its initiation sequence.
Use the Weld Mode Selection Switch to
select LIFT TIG or HF TIG Mode.
Select an appropriate welding current for
the job by setting the knob on the machine
front panel.
HF Start
When HF Start TIG is selected then the
electrode tip is bought close to the work
piece, but not touching.
Pressing the trigger will produce a high
voltage spark that will jump to the work
piece and initiate an arc.
HF TIG can be used where work piece
contamination by the electrode is a
concern. Also where repetitive starts causes
contamination of the electrode, which
produces an unstable arc.
1 32 4
Fig 12 Lift TIG Operation Procedure
LIFT TIG Operation
When the Welding mode is set to LIFT TIG
then the arc start can be achieved with the
following procedure.
1 Touch the electrode lightly against the
work piece.
2 Press the torch trigger switch. The
shielding gas will start to flow and a
small current will pass through the
electrode.
3 While still holding the electrode against
the work piece, roll the hand piece over
until the cup rests on the work piece.
Use the cup as a pivot point to roll the
hand piece over allowing the electrode to
lift of the work piece.
The arc will ignite.
4 Immediately lift the cup of the work
piece, the current will rise to the welding
level within the up-slope time.
Use of a copper striking plate can be
used to avoid electrode contamination.
The electrode can also be contaminated
by contact with the filler rod.
A contaminated electrode produces an
unstable arc. If this occurs regrind the
electrode tip.
7 Basic Welding Information