Weldclass WeldForce WF-140ST User manual

WF-140ST / WF-180ST
© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03 1
Edition 1
OPERATING INSTRUCTIONS
IMPORTANT!
To qualify for full 36 month warranty, you must register within 30 days of purchase. See inside for details.
Read these Operating Instructions Completely before attempting to use this machine. Save this manual and
keep it handy for quick reference. Pay particular attention to the safety instructions we have provided for
your protection. Contact your distributor if you do not fully understand anything in this manual.

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2© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03
Congratulations & thank you for choosing WeldForce!
The WeldForce range from Weldclass provides market leading value, features and durability. WeldForce
machines have been designed with emphasis on robust construction, with simple and functional operation.
Register Your Warranty Now
Standard warranty without registration is 24 months.
To qualify for an extended full 36 month warranty on your purchase you must register within 30 days of
purchase.
Please register your warranty now by going to:
www.weldclass.com.au/weldforcewarranty
You will need;
a) A copy of your purchase invoice / receipt.
b) Your machine serial number which can be found on the technical data plate on the back of the
machine, or on the outside of the box that your machine came in.

WF-140ST / WF-180ST
© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03 3
1CONTENTS
1CONTENTS...............................................................................................................................................3
2BASIC SPECIFICATIONS ............................................................................................................................6
3KNOW YOUR MACHINE...........................................................................................................................7
3.1 Machine Front................................................................................................................................7
3.2 Machine Rear .................................................................................................................................7
3.3 Control Panel..................................................................................................................................8
3.4 Symbols chart.................................................................................................................................9
4CONTROLS EXPLAINED..........................................................................................................................10
4.1 Weld Process Selection ................................................................................................................10
4.2Setting Selection...........................................................................................................................10
4.2.1 Amps ........................................................................................................................................11
4.2.2 Hot Start Adjustment (Stick) ....................................................................................................11
4.2.3 Arc Force Adjustment (Stick)....................................................................................................11
4.3 Error/Over Temperature Indicator Light.......................................................................................11
4.4 Optional VRD Function.................................................................................................................11
5POWER SUPPLY .....................................................................................................................................12
5.1 Electrical Connection....................................................................................................................12
5.2Extension Leads............................................................................................................................12
5.3 Generator Use..............................................................................................................................12
5.3.1 Generator Size..........................................................................................................................12
5.3.2 Generator Quality & Warranty Limitations..............................................................................12
5.3.3 3 Golden Rules of Generator use.............................................................................................13
6OPERATING ENVIRONMENT..................................................................................................................14
6.1 Location........................................................................................................................................14
6.2 Ventilation....................................................................................................................................14
7BASIC OPERATION.................................................................................................................................15
7.1 Stick (MMA) Welding Operation ..................................................................................................15
7.2 Lift TIG Operation.........................................................................................................................16
8ACCESSORIES, SPARE PARTS & CIRCUIT DIAGRAMS..............................................................................17
8.1 TIG Torch and Spares (Optional Extra): ........................................................................................17
8.2 Optional Accessories....................................................................................................................18
8.3 Machine Spare Parts: ...................................................................................................................18
8.4 Primary Schematic Circuit Diagram..............................................................................................20
9CARE & MAINTENANCE.........................................................................................................................21
9.1 Keep your Welding Machine in Top Condition.............................................................................21
9.2 Storing the Welder .......................................................................................................................21

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4© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03
10 GENERAL GUIDE TO WELDING .........................................................................................................22
10.1 Duty Cycle Rating .........................................................................................................................22
10.2 Choosing a Welding Process – Stick or TIG?.................................................................................22
10.2.1 The Stick (MMA) Process .....................................................................................................22
10.2.2 The TIG Process....................................................................................................................23
10.3 Joint Preparations.........................................................................................................................24
11 STICK (MMA) BASIC WELDING GUIDE..............................................................................................26
11.1 Size of Electrodes .........................................................................................................................26
11.2 Storage of Electrodes ...................................................................................................................26
11.3 Electrode Polarity.........................................................................................................................26
11.4 Effects of Stick (MMA) Welding on Various Materials..................................................................26
11.4.1 High Tensile and Alloy Steels................................................................................................26
11.4.2 Manganese Steels ................................................................................................................26
11.4.3 Cast Iron...............................................................................................................................26
11.5 Types of Electrodes ......................................................................................................................27
11.5.1 MILD STEEL: .........................................................................................................................27
11.5.2 CAST IRON:...........................................................................................................................27
11.5.3 STAINLESS STEEL: .................................................................................................................27
11.6 Suggested Settings for Typical Stick (MMA) Applications ............................................................27
11.7 MMA Welding Techniques ...........................................................................................................28
11.7.1 A Word for Beginners...........................................................................................................28
11.7.2 The Welder...........................................................................................................................28
11.7.3 Striking the Arc.....................................................................................................................28
11.7.4 Arc Length............................................................................................................................29
11.7.5 Rate of Travel .......................................................................................................................29
11.8 Making Welded Joints ..................................................................................................................30
11.8.1 Butt Welds............................................................................................................................30
11.8.2 Fillet Welds...........................................................................................................................31
11.8.3 Vertical Welds ......................................................................................................................32
11.8.4 Overhead Welds...................................................................................................................33
11.9 MMA (Stick) Troubleshooting.......................................................................................................34
12 TIG BASIC WELDING GUIDE..............................................................................................................36
12.1 TIG Electrode Selection and Preparation .....................................................................................36
12.1.1 Electrode Polarity.................................................................................................................36
12.1.2 Preparing Tungsten for DC Electrode Negative (DCEN) Welding .........................................37
12.1.3 Shielding Gas for TIG Welding..............................................................................................38
12.1.4 Typical TIG Welding Settings................................................................................................38
12.2 TIG Welding Troubleshooting.......................................................................................................39
13 KNOWLEDGE & RESOURCES.............................................................................................................40

WF-140ST / WF-180ST
© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03 5
14 SAFETY..............................................................................................................................................40
14.1 Store and Retain this Manual.......................................................................................................40
14.2 Important Safety Information ......................................................................................................40
14.3 Welding Operation .......................................................................................................................40
14.4 Welding Safety Instructions & Warnings......................................................................................42
14.4.1 Personal Safety.....................................................................................................................43
14.4.2 Arc Rays can Burn Eyes and Skin..........................................................................................43
14.4.3 Noise Can Damage Hearing .................................................................................................43
14.4.4 Work Environment Safety ....................................................................................................44
14.4.5 Electricity Can Kill.................................................................................................................44
14.4.6 Fumes And Gases.................................................................................................................45
14.4.7 Fire & Explosive Risks...........................................................................................................46
14.4.8 Sparks & Hot Metal..............................................................................................................46
14.4.9 Gas Cylinders........................................................................................................................47
15 WARRANTY.......................................................................................................................................48
15.1 Warranty period...........................................................................................................................48
15.2 Warranty Includes and Covers......................................................................................................48
15.3 Warranty Excludes / Does Not Cover ...........................................................................................48
15.4 Warranty Conditions ....................................................................................................................49

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6© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03
2BASIC SPECIFICATIONS
Description
WeldForce WF-140ST
WeldForce WF-180ST
Part Number
WF-06170
WF-06171
Dimensions of Power Source (L x
W x H)
250 x 135 x 220mm
290 x 135 x 220mm
Weight of Power Source
4kg
4.5kg
Standard
AS 60974.1
Power Supply
240V +/- 15% 50hz Single Phase
Factory Fitting Supply Plug Rating
10A
15A
Effective Input Current (I1eff)
10A
15A
Maximum Input Current (I1max)
35A
38A
Output Terminals
Dinse™ style 10-25
Dinse™ style 35-50
Protection Class
IP23
Stick (MMA) Welding
Welding Current Output
10 – 140A
10 – 180A
Duty Cycle
140A / 25.6V @ 15%
70A / 22.8V @ 60%
55A / 22.2V @ 100%
180A / 27.2V @ 15%
90A / 23.6V % 60%
70A / 22.8V @ 100%
Nominal Open Circuit Voltage
55V
70V
MMA Electrode Size
1.6 – 3.2mm
1.6 – 4.0mm
TIG Welding
Welding Current Output
10 – 200A
10 -180A
Duty Cycle
140A / 15.6V @ 15%
70A / 12.8V @ 60%
55A / 12.2V @ 100%
180A / 17.2V @ 15%
70A / 12.8V @ 60%
55A / 12.2V @ 100%
Nominal Open Circuit Voltage
55V
70V
TIG Tungsten Size
1.6 – 2.4mm
1.6 – 3.2mm
Table 1
For full machine specifications, refer to technical data plate on back of machine – or go to:
www.Weldclass.com.au/WF-140MST / www.Weldclass.com.au/WF-180MST

WF-140ST / WF-180ST
© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03 7
3KNOW YOUR MACHINE
3.1 Machine Front
1. Carry Handle
2. Control panel
3. Positive (+) Welding Power Output Connection Socket
4. Negative (-) Welding Power Output Connection Socket
3.2 Machine Rear
5. Mains Power Switch
6. 240V AC Mains Power Input Lead
3
4
2
1
Figure 1
5
6
Figure 2

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8© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03
3.3 Control Panel
7. Power On Indicator Light
8. Stick (MMA) Process Indicator Light
9. VRD Active Indicator Light
10. Process Selection Button (Process)
11. Lift TIG Process Indicator Light
12. Selection Knob
13. Arc Force Setting Indicator Light
14. Hot Start Setting Indicator Light
15. Amps Setting Indictor Light
16. Error/Over Temperature Indicator Light
17. LCD Readout
Figure 3
10
14
7
8
9
11
12
13
15
16
17

WF-140ST / WF-180ST
© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03 9
3.4 Symbols chart
I
Power On
O
Power Off
Power On
Indication
Fault Indication
Caution / Hazard
Read Instruction
Manual
VRD Active
TIG Function
Stick/MMA
Function
Hot Start
Arc Force
Amperage (current)
output
Voltage output
Increase/Decrease
Single phase
Inverter power
source DC
Stick/MMA
(SMAW) Function
TIG (GTAW)
Function
Power Supply
Connection
Single Phase
Direct Current (DC)
–
Negative
+
Positive
Hertz (cycles/sec)
Duty Cycle
Amperage
(Current)
Voltage
Table 2

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10 © Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03
4CONTROLS EXPLAINED
4.1 Weld Process Selection
1. Press ‘Process’ button (10) until the desired Welding Process Indicator Light (8 or 11) is lit.
4.2 Setting Selection
1. Press the Selection Knob (12) down until the desired Setting Indicator Light is illuminated (13, 14
or 15)
2. Rotate the Selection Knob (12) to adjust parameter for the chosen Setting
Figure 5
1
2
Figure 4
1

WF-140ST / WF-180ST
© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03 11
4.2.1 Amps
This is the output welding amperage.
4.2.2 Hot Start Adjustment (Stick)
Hot Start setting is adjustable from 0 – 10. Hot start provides extra power when the weld starts to
counteract the high resistance of the electrode and workpiece as the arc is started. It makes igniting the
electrode easier and prevents it from sticking when cold. 0 is Hot-Start off, 10 is maximum Arc Force
(around 20-30A higher than the set welding current/amps).
4.2.3 Arc Force Adjustment (Stick)
Arc Force setting is adjustable from 0 – 10. (Sometimes called ‘Dig’ or ‘Arc Control’). A Stick welder is
designed to produce constant output current (CC). This means with different types of electrode and arc
length; the welding voltage varies to keep the current constant. This can cause instability in some
welding conditions as Stick welding electrodes will have a minimum voltage they can operate with and
still have a stable arc.
Arc Force control boosts the welding power if its senses the welding voltage is getting too low. The
higher the arc force adjustment, the higher the minimum voltage that the power source will allow. This
effect will also cause the welding current to increase. 0 is Arc Force off, 10 is maximum Arc Force (around
20-30A higher than the set welding current/amps). This is practically useful for electrode types that have
a higher operating voltage requirement or joint types that require a short arc length such as out of
position welds.
4.3 Error/Over Temperature Indicator Light
Error/Over Temperature Indicator Light (16) illuminates when duty cycle is exceeded and thermal
protection is activated. When thermal protection is activated, welding output will be disabled until
machines cools sufficiently and overload indicator lamp goes out.
This may also activate if there are electronic circuit failure issues.
4.4 Optional VRD Function
This function is disabled by default. To have this feature enabled please contact your WeldForce
distributor.
When enabled VRD function reduces the welding machines’ open circuit voltage (OCV, or no-load
voltage) to a much safer level of U0<24V. OCV is the voltage measured across the positive and
negative terminals when welding is not in progress.
The VRD function will turn on full welding power/voltage when the resistance between the electrode
and work piece is less than 200 Ohms (i.e. metal to metal contact).
When the VRD function is active, the VRD Active Indicator Light (9) is illuminated.
Figure 7
Figure 6

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12 © Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03
5POWER SUPPLY
5.1 Electrical Connection
WF-140ST
The WF-140ST is designed to operate on a 10A 240V AC power supply.
WF-180ST
The WF-180ST is designed to operate on a 15A 240V AC power supply.
5.2 Extension Leads
If an extension cord must be used, it should be minimum cable core size 2.5mm2.
Using extension leads of over 50m is not recommended.
5.3 Generator Use
This machine is designed with generator use in mind and incorporates wide voltage tolerance and
intelligent voltage sensing technology to provide maximum protection from power fluctuations that
can occur with motor generators.
5.3.1 Generator Size
WF-140ST
Generator size should be not less than 7kva. An 7kVa generator may not provide enough power to
enable full output and duty of this welder.
To ensure full output and duty cycle of this welder a minimum recommended generator size is
minimum 8kVa.
WF-180ST
Generator size should be not less than 8kva. An 8kVa generator will not provide enough power to
enable full output and duty of this welder. However, it should provide sufficient power to run a
general purpose 3.2mm with reasonable duty cycle.
To enable full output and duty cycle of this welder a minimum recommended generator size is
minimum 10kVa.
5.3.2 Generator Quality & Warranty Limitations
Avoid using poor, low quality generators as these have the greatest risk of power spikes etc. A
suitable quality generator should have a THD (total harmonic distortion) rating of no more than 6%.
Most reputable generator suppliers will be able to specify the THD ratings on their product.
Any damage caused by poor quality generator power supply or incorrect use is not covered under
warranty.

WF-140ST / WF-180ST
© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03 13
5.3.3 3 Golden Rules of Generator use
When running an inverter welder off a generator there are 3 VERY IMPORTANT Golden Rules that
MUST be followed:
1. Do NOT plug welder into generator until AFTER generator has been started up and is running
smoothly
2. UNPLUG welder from generator BEFORE shutting generator down/turning generator off
3. NEVER let your generator run out of fuel whilst the welder is plugged in.
Following these Golden Rules will significantly reduce the risk of any damage resulting from
generator power supply.

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14 © Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03
6OPERATING ENVIRONMENT
6.1 Location
The machine has electrical components and control circuit boards which may be damaged by excessive
moisture, dust and dirt, so a clean and dry operating environment is important for reliable product life.
The enclosure design of this power source meets the requirements of IP23S as outlined in AS60529.
This provides adequate protection against solid objects (greater than 12mm), and direct protection
from vertical drops. Under no circumstances should the unit be operated or connected in a micro
environment that will exceed the stated conditions. For further information please refer to AS 60529.
6.2 Ventilation
Adequate ventilation is required to provide proper cooling for the machine. Ensure that the machine
is placed on a stable level surface where clean cool air can easily flow through the unit.

WF-140ST / WF-180ST
© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03 15
7BASIC OPERATION
7.1 Stick (MMA) Welding Operation
1. Connect the earth cable quick connector to the Negative (-) Welding Power Output Socket (4)
2. Connect the earth clamp to the work piece. Contact with the work piece must be firm contact
with clean, bare metal, with no corrosion, paint or scale at the contact point.
3. Insert an electrode into the electrode holder and connect the electrode holder and work lead to
the Positive (+) Welding Power Output Socket (3).
NOTE: This polarity connection configuration is valid for most GP (General Purpose)
MMA electrodes. There are variances to this, also many electrodes will run in either
polarity setting (electrodes positive or electrode negative, with slight difference in
performance. If in doubt, check the electrode specifications or consult the electrode
manufacturer.
4. Connect the machine to suitable power. Switch the mains power switch (5) to ‘on’ to power up
the machine.
5. Set welding process selector to ‘Stick’ (refer to 4.1)
6. Select the required output current using the Selection Knob (12). The LCD Readout (17) will
display the set amperage output.
7. Adjust special Function settings if required (refer to 4.2)
8. You are now ready to weld!
Figure 8

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16 © Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03
7.2 Lift TIG Operation
NOTE: Lift TIG operation requires an optional manual valved TIG torch, argon gas cylinder & regulator.
NOTE: The WF-140ST / WF-180ST is a DC (Direct Current) output welder only, this means that it is unable
to TIG weld reactive metals such as Aluminium alloys and Brass (which require AC output). DC TIG output
is suitable for steel, stainless steel and copper.
1. Connect the earth cable to the Positive (+) Welding Power Output Socket (3)
2. Connect the earth clamp to the work piece. Contact with the work piece must be firm contact
with clean, bare metal, with no corrosion, paint or scale at the contact point.
3. Insert TIG torch power connection into the Negative (-) Welding Power Output Socket (4)
4. Connect valve TIG torch gas line to the regulator, ensuring all connections are tight.
5. Open gas cylinder valve and adjust regulator. Flow should be between 5-10 l/min depending on
application. Re-check regulator flow pressure with torch valve open as static gas flow setting may
drop once gas is flowing.
6. Connect the machine to suitable power. Switch the mains power switch (5) to ‘I’ to power up the
machine.
7. Set welding process selector to ‘TIG’ (refer to 4.1)
8. Select the required output current using the Selection Knob (12). The LCD Digital Readout (17)
will display the set amperage output.
9. You are now ready to weld!
Figure 9

WF-140ST / WF-180ST
© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03 17
8ACCESSORIES, SPARE PARTS & CIRCUIT
DIAGRAMS
8.1 TIG Torch and Spares (Optional Extra):
The compatible TIG torch for this machine is the Weldclass 3-TTU2917V/4 torch.
To view this torch and parts, go to: www.weldclass.com.au
Part No.
Description
3-TTU2917V/4
Complete TIG Torch – with Valve – 4m
3-TTU2917V/8
Complete TIG Torch – with Valve – 8m
P3-TB17V
Torch Body - 17 Standard (Valved)
P3-TB17FV
Torch Body - 17FV Flexible (Valved)
WC-57Y02P
Back cap – Long Pk2
WC-57Y05P
Back cap – Medium Pk2
WC-57Y04P
Back cap – Short Pk2
P3-10N23
Collet – 1.6mm
P3-10N24
Collet – 2.4mm
P3-10N25
Collet – 3.2mm
P3-10N31
Collect Body – 1.6mm Pk2
P3-10N32
Collect Body – 2.4mm Pk2
P3-10N28
Collect Body – 3.2mm Pk2
P3-10N49
TIG Ceramic Cup - #5 7.9mm Pk2
P3-10N48
TIG Ceramic Cup - #6 9.5mm Pk2
P3-10N47
TIG Ceramic Cup - #7 11.1mm Pk2
P3-10N46
TIG Ceramic Cup - #8 12.7mm Pk2
P3-10N45
TIG Ceramic Cup - #10 15.8mm Pk2
WC-05192
TIG Tungsten RE4 – 1.6mm Pk10
WC-05193
TIG Tungsten RE4 – 2.4mm Pk10
WC-05194
TIG Tungsten RE4 – 3.2mm Pk10
Table 3
Figure 10

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18 © Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03
8.2 Optional Accessories
Optional Accessories
Part No.
Drive Roller
WC-06235
Welding Trolley
WC-01775
Welding Gloves
Table 4
8.3 Machine Spare Parts:
For machine parts, go to www.weldclass.com.au/machines or contact your Weldclass distributor.
WF-140ST
Ref.
Description
1
Handle
2
Cover
3
Rear panel
4
On/Off switch
5
Power cable clip
6
Cooling fan assembly sheet
7
Cooling fan
8
Support pillar
9
Heatsink
10
Base panel
11
Recovery diode
12
Main PCB
13
Front panel
14
Euro socket
15
Front panel assembly sheet
16
Knob
17
Control PCB
18
Heatsink
19
Heatsink
20
Heatsink
21
Insulation part
22
IGBT
23
Rectifier
24
EMC PCB assembly sheet
25
EMC PCB
Table 5
WF-180ST
Ref.
Description
1
Handle
2
Cover
3
Heatsink
4
Rear panel
5
On/Off switch
6
Power cable clip
7
Cooling fan assembly sheet
8
Cooling fan
9
Heatsink
10
Inductor
11
Base panel
12
Assembly part
13
Recovery diode
14
Heatsink
15
Front panel
16
Euro socket
17
Front panel assembly sheet
18
Knob
19
Control PCB
20
IGBT
21
Insulation part
22
Recovery diode
23
Main PCB
24
Insulation part
25
Rectifier
26
EMC PCB assembly sheet
27
EMC PCB
Table 6

WF-140ST / WF-180ST
© Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03 19
WF-140ST
Figure 11
WF-180ST
Figure 12

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20 © Weldclass | E.&O.E. | Edition 1.1 | 2019.05.03
8.4 Primary Schematic Circuit Diagram
Figure 13