WELDTECH WT200MP User manual

OPERATING INSTRUCTIONS
WT200MP
200A MULTI-PROCESS
MIG/MMA(STICK)/TIG WELDER
www.weldtech.net.nz

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Congratulations on your new Weldtech product!
The Weldtech range from Euroquip uses latest technology design and engineering
to produce welding products that combine market leading value and features with
durability. Designed for discerning operators who seek professional results and
product quality without the price tag of a full professional setup. Design emphasis
is placed on simple, functional design and operation. Weldtech product is subject
to stringent quality control and designed and manufactured to NZ & Australian
standards.
Common use of Weldtech products include:
 • LightEngineering
 • Automotive
 • Home/HobbyEngineering
 • Farming
 • Maintenance&Repairs
Forindustrialweldingsolutions,checkouttheStratarangefromEuroquip:
www.strata.co.nz
Euroquip is a market leading provider of innovative power equipment solutions
to a wide range of industries across New Zealand and Australia. Key product
categories are; welding equipment, air compressors, power generators and
cleaning equipment.
Euroquip’s slogan is ‘empowering industries’, nd out more about the advantage
Euroquip brings at www.euroquip.co.nz.
Providing exceptional product support is a key component of Euroquip’s market
leading customer advantage focus. As part of this program, it is required for all
products to be registered with Euroquip to qualify for product support. Products
not registered with Euroquip are supported by a base 12 month warranty only.
Sparepartsandtechnicalsupportwillnotbeavailableforanunregisteredproduct
outside of this base warranty period. If a Euroquip dealer has not already registered
your product, please register it online at www.euroquip.co.nz. To request a physical
registration form, please contact Euroquip customer service on 0800 387 678.
We Appreciate Your Business!

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WT200MP Welding Machine
www.weldtech.net.nz
Contents
Welcome to Euroquip..........................................2
KnowYourMachine..............................................5
ControlsExplained.................................................5
QuickStartGuide....................................................6
Tips & Tricks.................................................................9
WeldingSettings...................................................10
Accessories..............................................................11
Care&Maintenance............................................12
MIGBasicWeldingGuide..............................12
MIGWeldingTroubleshooting....................16
MMA(Stick)BasicWeldingGuide................18
MMA(Stick)Troubleshooting.......................24
TIGBasicWeldingGuide...................................25
TIGTroubleshooting...........................................27
Knowledge&Resources..................................28
Safety .........................................................................28
Warranty....................................................................33

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200A - INVERTER MULTI-PROCESS WELDER
WT200MP
Powerful - 200A welding power up to 12mm steel thickness
Portable - Only 13kg super light weight and portable
Multi-Process - All in one machine for ARC, MIG and TIG
• Compact design - only 13kg
• MIG, TIG and ARC welding
• Latest IGBT inverter technology for the best results
• Inductance adjustment for precise weld control
• Optional spool gun available for aluminium and silicon bronze
• MIG 60% duty cycle @160A, ARC 60% duty cycle @ 130A
• 230V single phase on 15A plug
• Live digital displays for accurate feedback of welding output
• Stepless voltage and wire feed control for optimum weld control
• Lift TIG with optional TIG torch
• 3m Binzel Euro Connect MIG torch
• Exceptional results on gasless welding!
Cutting edge IGBT Inverter Technology with MIG, TIG and ARC processes available.
Produces professional results on workshop or on-site projects!
With 15A Plug - Ideal for workshop projects - cars, trailers and structural steel!
TAKES
15KG SPOOL
OF WIRE
OPTIONAL
SPOOL GUN
FOR
ALUMINIUM
(#13323)
60% @ 130A - MIG
60% @ 120A - ARC
Dimensions: (L x W x H) 485 x 220 x 390mm
Weight: 13kg
Input Power: 230V, 15A
Max. Input Current: 29.4A
Generator Capacity: 7kVA
Output Power:
Duty Cycle:
Electrode Size: 1.6 - 4.0mm
Wire Size: 0.6, 0.8, 0.9, 0.10
Spool Size: 5kg / 15kg
60% @ 160A - MIG
60% @ 130A - ARC
40 - 200A - MIG
30 - 170A - ARC
Welding Gloves
(#AWG02)
4 Sensor Auto Helmet
with grind
function
(#DW3000)
2 Sensor Auto Helmet
(#DW2500)
Flip Front Helmet
(#AFF1000)
Welding Magnet
(#WMG05)
Spool Gun for Alloy
(#13323)
Tips
0.6 (#MMT1506)
0.8 (#MMT1508)
0.9 (#MMT1509)
Chipping Hammer
(#SPCH)
TIG Torch
(#TWP17V-12-2D + CP3550)
Optional accessories to help you get the job done!
MIG Wire
0.6 (#MWM5KG06)
0.8 (#MW5KG08)
0.9 (#MW5KG09)
Flux Cored
0.8 (#MWMS08FC)
0.9 (#MWMS09FC)
0.9 (#MW5KG09FC)
MWMS = Mini Spool
MW5KG = 5kg
FC = Flux Cored

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WT200MP Welding Machine
www.weldtech.net.nz
Know Your Machine
1. MIG Torch Euro Connection
2. Spool Gun Connection Socket
3. Spool Gun Switch
4. LCD Current Meter
- Displays output current (amps) in real time*
5. LCD Voltage Meter
- Displays output voltage in real time*
6. Welding Output Mode Switch
- Sets power source in MIG, MMA or Lift TIG mode*
7. Overload Indicator Lamp*
8. Welding Voltage Adjustment Knob
- Adjusts welding voltage in MIG mode*
9. MIG Wire Feed Speed Adjustment Knob/ MMA
Current Adjustment Knob*
10. MIG inductance Control Knob*
11. Cooling Fan Inlet
12. Positive (+) Welding Power Output Connection Socket
13. Negative (-) Welding Power Output Connection Socket
14. MIG Torch Power Connection Lead
15. Shielding Gas Inlet Connection
16. 230V AC Mains Power Input Lead
17. Mains Power Switch
18. Wire Spool Holder
19. Wire Drive Inlet Guide
20. Wire Feed Tension Adjustment
21. Wire Feed Tension Arm
22. Wire Drive Roller Retainer
23. Wire Drive Roller (Obscured)
LCD Current & Voltage Display Meters
These indicate the actual voltage and current read-
ings at the output terminals of the welding machine.
The current meter should read ‘0’ except when weld-
ing is actually taking place. The voltage meter will
indicate output voltage during welding and the
welding open circuit voltage when the machine
is powered up but not welding. In MIG mode the
open circuit voltage will only appear once the torch
is triggered to activate the circuit, in MMA and Lift
TIGmode,theopencircuitvoltagewillshowonthe
display continuously. The digital meters are very sen-
sitive and accurate, so it is not abnormal to observe
some small uctuations on them when the machine
is at rest.
Controls Explained
1
2
3
4
5
67
89
10
11
12
13
14
17
16
15
18
19
20
21
22
23

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Quick Start Guide
Electrical Connection
TheWT200MPisdesignedtooperateona15A230V
AC power supply. If an extension cord must be used,
it should be a heavy duty version with a minimum
cablecoresizeof2.5mm2.Itisrecommendedtouse
theEuroquipindustrialduty15Aextensionlead,part
number16895.
Operating Environment
Adequate ventilation is required to provide proper
coolingfortheWT200MP.Ensurethatthemachine
is placed on a stable level surface where clean cool
aircaneasilyowthroughtheunit.TheWT200MP
has electrical components and control circuit boards
which may be damaged by excessive dust and dirt,
so a clean operating environment is essential.
Mig Voltage & Mig Wire Speed / MMA
& Lift Tig Current Control Knobs
MIG Welding Mode
TheMIG voltagecontrolis essentially thepower in
the welding arc that sets the heat. The wire speed
feed simply controls the rate at which the welding
wire is fed into the weld pool.
Foranyvoltagepositionsetting,therewillbeaspe-
cic corresponding ‘sweet spot’ in the wire feeding
speed that will give the smoothest and most stable
welding arc. The correct wire feeding speed for a giv-
en voltage setting is aected by welding wire type
and size, shielding gas, welding material and joint
type.
It is recommended to set the welding voltage as
desired and then slowly adjust the wire speed un-
til the arc is smooth and stable. When reaching this
point, if the penetration/ heat input is too much/
not enough, adjust the voltage setting and repeat
the process. If the operator is not able to achieve a
smooth and stable arc with the desired heat input
fortheweld,itislikelythatachangeinwiresizeand/
orshieldinggastypeisrequired(assumingallother
factorsarecorrect).
A chart with recommended settings using this ma-
chine for common welding applications is located
on the underside 0f the wire feeder cover door and
further on in this manual.
MMA/ Lift TIG Welding Mode
The current control knob sets the target welding
output current for either mode selected. The voltage
knobhasnoeectinMMAorTIGmode.
MIG Inductance Control- Inductance adjustment
controls the rate of the current rise and fall as the
welding wire contacts the workpiece (known as a
short circuit). More inductance increases the short
circuit time and decreases the short circuit frequency
rate. This causes a wider and more penetrating arc,
useful for thicker weld joints. Less inductance will
create a narrow more focused arc. This eect can also
be used to ne tune the arc to produce less splatter.
Wire speed, wire size and type, shielding gas will all
change the eect that the inductance setting has on
the welding arc. As a general rule, CO2 based shield-
ing gas will weld more smoothly with increased in-
ductance, while argon shielding gas will perform
better with less inductance. Inductance setting will
havenoeectonMIGspraytransferprocess(asop-
posedtoshortcircuitprocess),MMAorTIGwelding
process.
Lift TIG Mode
LiftTIGisanarcignitionsystemforbasicTIGwelding
that removes the need to ‘scratch’ start or strike the
tungsten on the work piece to start the arc, which
can have a negative eect on the weld quality due
totungstencontamination.Liftarcstartingworksby
gently touching the tungsten on the work piece and
then lifting it o. The control circuit will sense when
the tungsten is removed from the work piece and
send a pulse of electricity through the torch that will
causetheTIGarctoinitiate.
Overload Indicator Lamp
Lights when duty cycle is exceeded and thermal
protection is activated. When thermal protection is
activated, welding output will be disabled until ma-
chines cools suciently and overload indicator lamp
goes out. Also may activate with inverter circuit fail-
ure issues.

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WT200MP Welding Machine
www.weldtech.net.nz
Basic Operation - MIG Welding
1. Fitting Wire Spool
1.1 Openthewirefeedercompartmentdoor.Remove
thewirespoolholder(18)bythreadingitanticlock-
wise.Ifusing5kg/D.200spool,checkthatthe5kg
spoolspacersleeveisttedtothespoolholder.Fit
the wire spool to spool holder, ensuring that the
wire exits the spool towards the wire feeder from
bottom the spool.
1.2 To replace the spool holder, set the spool brake
tension by adjusting the spool tension adjust-
ment hex screw in the middle of the spool holder.
Clockwise to increase spool brake tension and an-
ti-clockwise to decrease. The spool brake tension
should be set so that the spool can rotate freely,
but does not continue to rotate once the wire feed
stops. This may need to be adjusted as the wire is
used up and the spool weight decreases.
WARNING!
Excessive spool brake tension will cause wire feeding
issues and aect welding performance as well as
premature failure/ wear of wire feed components.
Insucient brake tension will cause the spool to
‘freewheel’ and the welding wire will unravel from
the spool (known as a ‘birds nest’)
1.3 Feed the wire from the spool through the wire
driveinletguide(19)intothewirefeeder.
2. Loading Wire Feeder
2.1 Release the wire feed tension arm (21) by pivot-
ingthewirefeedtensionadjustmentlever(20)to-
wards you from the vertical ‘locked’position.
2.2 Checkthewiredriveroller(23)groovematchesthe
selectedMIGwiretypeandsize.Thedriverollerwill
have two dierent sized grooves; the size of the
groove in use is stamped on the side of the drive
roller.Foruxcored‘soft’wire,suchasthatusedin
gaslessMIGwelding,thedriverollergroovehasa
serratedprole(knownasknurled).Forsolidcore
‘hard’MIGwire,thedriverollergrooveusedhasa
‘v’ shaped prole. For Aluminum solid core‘soft’
MIGwire,thedriverollerrequiredhasa‘u’shaped
groove. If necessary, remove and change the drive
rollerbyunthreadingthedriverollerretainer(22).
 Once the correct drive roller (23) is selected and
tted and the drive roller retainer (22) is secured
in place, manually feed the wire through the wire
drive inlet guide (19), through the drive roller
groove and into the outlet wire guide tube. En-
suring that the wire is correctly seated in the drive
roller groove, replace the wire feed tension arm
(21)andlockitintoplacebypivotingthewirefeed
tensionadjustmentlever(20)backtothevertical
position.
2.3 Adjusting wire feed tension. This is accomplished
by winding the knob on the tension adjustment
lever (20). Clockwise will increase tension, anti-
clockwise will decrease drive tension. Ideal tension
is as little as possible, while maintaining a consist-
ent wire feed with no drive roller slippage.
2.4 Check all other causes of excess wire feeding fric-
tioncausingslippagerst,suchas;incorrect/worn
drive roller, worn/ damaged torch consumables,
blocked/ damaged torchwire guide liner, before
increasing wire feed tension. There is a number
scaleonthetensionadjustmentlever(20)toindi-
cate the adjustment position. The higher the num-
ber indicated, the higher the tension that is set.
WARNING!
Before changing the feed roller or wire spool, ensure
that the mains power is switched o.
WARNING!
The use of excessive feed tension will cause rapid
and premature wear of the drive roller, the support
bearing and the drive motor/ gearbox.
2.5 ConnecttheMIGTorchEuroConnectortotheMIG
torch Euro connection socket (1) on the front of
themachine.Securebyrmlyhandtighteningthe
threadedcollarontheMIGTorchconnectorclock-
wise.
2.6 Check that the correct matching MIG wire, drive
roller(23)andMIGtorchtiparetted.
2.7 Connect the machine to suitable mains power us-
ing the mains input power lead (16). Switch the
mains power switch (17) to‘on’ to power up the
machine.Settheweldingmodeswitch(6)to‘MIG’
position.
2.8 You are now ready to feed the wire through the
torch. With the wire feeder cover open, pull the
triggeroftheMIGtorchtocheckthatthewireis
feeding smoothly through the feeder and into the
torch.
2.9 Setthewirefeedingspeedknob(9)tomaximum.
With the torch tip removed from the torch and the
torchlaidoutasstraightaspossible,depressMIG
torch trigger until the wire feeds out through the

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endoftheMIGtorch.ReplacethetipontheMIG
torch and trim o any excess wire.
3. Gasless Welding Operation
3.1 Connect the earth cable quick connector to the
positive welding power output socket (12). Con-
nect the earth clamp to the work piece. Contact
with the work piece must be rm contact with
clean, bare metal, with no corrosion, paint or scale
at the contact point.
3.2 Connect the MIGpowerconnection lead (14) to
the negative welding power output socket (13).
Note if this connection is not made, there will be
no electrical connection to the welding torch!
3.3 Settheweldingvoltageadjustmentknob(8),wire
speed control knob (9) and inductance control
knob (10) to the desired positions.You are now
ready to weld!
4. Gas MIG Welding Operation
NOTE: Gas MIG welding will require a gas cylinder. (Argon
mix or CO2)
4.1 Connect the earth cable quick connector to the
negativeweldingpoweroutputsocket(13).Con-
nect the earth clamp to the work piece. Contact
with the work piece must be rm contact with
clean, bare metal, with no corrosion, paint or scale
at the contact point.
4.2 Connect the MIGpowerconnection lead (14) to
the positive welding power output socket (12).
Note if this connection is not made, there will be
no electrical connection to the welding torch!
4.3 Connect the gas regulator to a gas cylinder (not
includedwithmachine)andconnectthegashose
from the regulator to the gas inlet on the rear of
themachine(15).Ensureallhoseconnectionsare
tight. Open gas cylinder valve and adjust regulator,
owshouldbebetween10-25L/mindepending
onapplication.Re-checkregulatorowpressure
with torch triggered as static gas ow setting may
drop once gas is owing.
4.4 Settheweldingvoltageadjustmentknob(8),wire
speed control knob (9) and inductance control
knob (10) to the desired positions.You are now
ready to weld!
MIG welding with aluminium provides a unique
challenge, due to the low column strength and
surface friction of the wire. This causes the wire
to deform more as it is pushed through the feed
mechanism and the torch wire delivery liner, great-
lyincreasing friction. Because good MIG welding
results are dependent on a smooth wire feed, cer-
tain changes must be made to the wire feed sys-
tem to minimise friction caused issues.
 Forastandard‘push’fedtorch,alengthofnolong-
er than 3m cable should be used, as well as the
torch feed liner must be changed to a special Tef-
lon/PVCliner,rather than the conventionalsteel
liner. Also the correct style drive roller must be
used and specic Aluminium rated torch contact
tip(orastandardtipinonesizeoversize,e.g0.8mm
aluminiumwire,usestandard1.0mmcontacttip).
For this reason, it is quite common for operators
tohavean extra MIGtorchspecically set upfor
aluminium use, if the machine is used for weld-
ing steel as well. Another option to overcome the
friction issues is using a spool gun, which will give
better results than a 3m push torch when welding
aluminium.TheWT200MPis spoolgun capable,
refer following section for use with a spool gun on
theWT200MP.
5. Spool Gun Operation
NOTE: Spool Gun is an optional extra for the WT200MP.
Spool gun part number: 13323
ThespoolgunisaveryusefuladditiontoaMIGwelder.
It canbeusedforalltypesofMIGwelding,but ithas
two primary advantages over a conventional‘push’wire
feeder. The main advantage is that distance that the
wire has to travel from the spool to the welding tip is
very short, compared with a conventional torch. This
greatly reduces the wire feeding friction and improves
the wire feed speed smoothness and consistency, thus
the welding quality is greatly improved. This is especial-
ly so with ‘soft’ wires such as Aluminium. It is dicult to
get Aluminium to feed smoothly in welding machines
equipped with standard design wire feeders, even with
special torch liners and short torch lengths.
The second advantage is that the gun can allow the
use of the small D100 wire spools at a distance from
thepowersource(Thisdistanceisonlylimitedbythe
lengthofthespoolgunlead).Thisisadvantageousfor
highcostwire,thatisnotusedcommonlysuchasStain-
lessSteelorMIGbrazingwire.Itsavestheoutlaycostfor
a much more expensive, larger D200 spool.
5.1 Connect the earth cable quick connector to the
negativeweldingpoweroutputsocket(13).Con-

9
WT200MP Welding Machine
www.weldtech.net.nz
nect the earth clamp to the work piece. Contact
with the work piece must be rm contact with
clean, bare metal, with no corrosion, paint or scale
at the contact point.
5.2 Connect the MIG power connection lead (14) to
the positive welding power output socket (12).
Note if this connection is not made, there will be
no electrical connection to the welding torch!
5.3 ConnectthespoolgunEuroConnectortotheMIG
torch Euro connection socket (1) on the front of
themachine.Securebyrmlyhandtighteningthe
threadedcollarontheMIGTorchconnectorclock-
wise. Connect the spool gun interface plug to the
spoolgunconnectionsocket(2).Setthespoolgun
switch(3)to‘on’position.
5.4 Connect the gas regulator to a gas cylinder (not
includedwithmachine)andconnectthegashose
from the regulator to the gas inlet on the rear of
themachine(15).Ensureallhoseconnectionsare
tight. Open gas cylinder valve and adjust regulator,
owshould be between10-25 l/min depending
onapplication.Re-checkregulatorowpressure
with torch triggered as static gas ow setting may
drop once gas is owing.
5.5 Settheweldingvoltageadjustmentknob(8),wire
speed control knob (9) and inductance control
knob (10) to the desired positions.You are now
ready to weld!
7. Lift TIG Operation
NOTE: Lift TIG operation requires an optional valve control
TIG torch, and argon gas cylinder.
7.1 Connect the earth cable quick connector to the
positive welding power output socket (12). Con-
nect the earth clamp to the work piece. Contact
with the work piece must be rm contact with
clean, bare metal, with no corrosion, paint or scale
at the contact point.
7.2 InsertTIGtorchpowerconnectionintothenega-
tive welding power output socket (13). Connect
valveTIGtorchgaslinetotheregulator,ensuring
all connections are tight.
7.3 Open gas cylinder valve and adjust regulator, ow
shouldbebetween5-10l/mindependingonap-
plication.  Re-check regulator ow pressure with
torch valve open as static gas ow setting may
drop once gas is owing.
7.4 Connectthemachinetosuitablemainspowerus-
ing the mains input power lead (16). Switch the
mains power switch (17) to‘on’ to power up the
machine.Settheweldingmodeswitch(6)to‘Lift
TIG’.
7.5 Selecttherequiredoutputcurrentusingthecur-
rentcontrolknob(9).Youarenowreadytoweld!
NOTE: The WT200MP 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. The New Model is the model in the range that
is designed for TIG welding Aluminium and its alloys.
Tips & Tricks
Duty Cycle Rating
Welding duty cycle is the percentage of actual weld-
ing time that can occur in a ten minute cycle. E.g.
20% at 160 amps - this means the welder can weld at
160 amps for 2 minutes and then the unit will need
to be rested for 8 minutes. All duty cycle ratings are
basedon an ambient air temperatureof 40°C with
50%humidity,whichistheinternationalstandardfor
such a rating. In an environment with temperature
s exceeding 40°C, the duty cycle will be less than
stated.Inambienttemperaturelessthan40°C,duty
cycle performance will be higher.
6. ARC/ MMA Welding Operation
6.1 Connect the earth cable quick connector to the
negativeweldingpoweroutputsocket(13) Con-
nect the earth clamp to the work piece. Contact
with the work piece must be rm contact with
clean, bare metal, with no corrosion, paint or scale
at the contact point.
6.2 Insert an electrode into the electrode holder and
connect the electrode holder and work lead to the
positiveweldingpoweroutputsocket(12).
NOTE: This polarity connection conguration is valid for
most GP (General Purpose) MMA electrodes. There are vari-
ances to this. If in doubt, check the electrode specications
or consult the electrode manufacturer.
6.3 Connect the machine to suitable mains power us-
ing the mains input power lead (16). Switch the
mains power switch (17) to‘on’ to power up the
machine.Settheweldingmodeswitch(6)to‘ARC’.
6.4 Selecttherequiredoutputcurrentusingthecur-
rentcontrolknob(9).Youarenowreadytoweld!

10
Welding Settings

11
WT200MP Welding Machine
www.weldtech.net.nz
Accessories Refertopage3forrelatedaccessoriesforthismachine or visit www.
weldtech.co.nz for a full range of consumables and accessories.
MP25 Torch Consumables Breakdown

12
Spare Parts for WT200MP
Part #: Description:
17257 CoolingFan
17252 WeldingModeSwitch
17261 WireFeederAssembly
17262 Potentiometer
17263 MainPCBAssembly
17264 GasSolenoid
17265 DigitalDisplayMeter
17266 ControlKnob-Blue
17267 Potentiometer 33K
17268 MIGTorchSocket
17269 SpoolHolderAssembly
17270 WireDriveRoller0.6/0.8mmVGroove
17271 WireDriveRoller0.9/1.0mmVGroove
17272 WireDriveRoller0.8/0.9mmKnurledGroove
13323 WeldtechSpoolGunAssembly
MB15KIT MIGConsumablesStarterKit-MB15.17512
 15kg-5kgspoolspacer
Care &
Maintenance
Keep your Welding Machine
in Top Condition
TheWT200MPdoesnotrequireanyspecialmainte-
nance, however the user should take care of the ma-
chine as follows:
• Regularlycleantheventilationslots.
• Keepthecasingclean.
• Checkallcablesbeforeuse.
• Checkelectrodeholders,worklead/clampsand
welding torches before use.
• Replacewornelectrodeholdersandearth
clamps, which do not provide a good
connection.
• Replaceworntorchconsumablepartsinatimely
manner.
• Replacewornwiredrivecomponentsinatimely
manner
• Use a soft cloth or brush to clean electrical
components. Do not use liquid cleaning products,
water or especially solvents.
• Donotusecompressedairtocleanelectrical
components as this can force dirt and dust
further into components, causing electrical short
circuits.
• Checkfordamagedparts.Donotusethewelder
with damaged parts.
If damaged, before further use, the welder must be
carefully checked by a qualied person to determine
that it will operate properly. Check for breakage of
parts, mountings and other conditions that may
aect its operation.
Have your welder repaired by an expert. An
authorised service centre should properly repair a
damaged part.
This appliance is manufactured in accordance with
relevant safety standards. Only experts must carry
out repairing of electrical appliances, otherwise
considerabledangerfortheusermayresult.Useonly
genuine replacement parts. Do not use modied or
non-genuine parts.
Storing the Welder
When not in use the welder should be stored in the
dry and frost-free environment.
WARNING! Before performing cleaning/main-
tenance, replacing cables / connections , make
sure the welding machine is switched o and
disconnected from the power supply.
MIG Basic
Welding Guide
Mig Basic Welding Techniques
Two dierent welding processes are covered in this
section(GMAWandFCAW),withtheintentionofpro-
vidingtheverybasicconceptsinMIGwelding,where
aweldinggunishandheld,andtheelectrode(weld-
ing wire) is fed into a weld puddle, and the arc is
shieldedbyagas(GMAW)oruxcoredwire(FCAW).

13
WT200MP Welding Machine
www.weldtech.net.nz
Gas Metal ARC Welding (GMAW).
Thisprocess,alsoknownasMIGwelding,CO2weld-
ing,MicroWireWelding,shortarcwelding,diptrans-
fer welding, wire welding etc., is an electric arc weld-
ing process which fuses together the parts to be
welded by heating them with an arc between a solid
continuous, consumable electrode and the work.
Shielding is obtained from an externally supplied
welding grade shielding gas. The process is normally
applied semi automatically; however the process
may be operated automatically and can be machine
operated. The process can be used to weld thin and
fairly thick steels, and some non-ferrous metals in all
positions.
GMAW Process
(Fig 1-1) ShieldingGas
MoltenWeldMetal
Nozzle
Electrode Arc
BaseMetal
SolidiedWeldMetal
Flux Cored Arc Welding (FCAW)
This is an electric arc welding process which fuses to-
gether the parts to be welded by heating them with
an arc between a continuous ux lled electrode
wireandthework.Shieldingisobtainedthroughde-
composition of the ux within the tubular wire. Ad-
ditional shielding may or may not be obtained from
an externally supplied gas or gas mixture. The pro-
cess is normally applied semi automatically; however
the process may be applied automatically or by ma-
chine.
It is commonly used to weld large diameter elec-
trodes in the at and horizontal position and small
electrode diameters in all positions. The process is
used to a lesser degree for welding stainless steel
and for overlay work.
FCAW Process
(Fig 1-2) Nozzle
(Optional)
FluxCored
Electrode
Arc
Base
Metal
Solidied
WeldMetal
Slag
Molten
Slag
MoltenMetal
ShieldingGas
(Optional)
Push Vertical Drag Pull
Position of MIG Torch
(Fig 1-3)
TheangleofMIGtorchtotheweldhasaneecton
the width of the weld.
The welding gun should be held at an angle to the
weldjoint.(SeeSecondaryAdjustmentVariablesbe-
low).
Holdthegunsothattheweldingseamisviewedat
all times. Always wear the welding helmet with prop-
er lter lenses and use the proper safety equipment.
CAUTION!
Do not pull the welding gun back when the arc is
established. This will create excessive wire exten-
sion (stick-out) and make a very poor weld.
The electrode wire is not energized until the gun
trigger switch is depressed. The wire may therefore
be placed on the seam or joint prior to lowering the
helmet.
(Fig 1-4) 5oto15o
LongitudinalAngle
Direction of Travel
90oTransverse
Angle
(Fig 1-5)
5oto15o
LongitudinalAngle 30oto 60o
Transverse
Angle
Direction
of Travel

14
Vertical Fillet Welds (Fig 1-6)
10o
LongitudinalAngle
Direction of Travel
10oto 20o
LongitudinalAngle
30oto 60o
Transverse
Angle
30oto 60o
Transverse
Angle
Direction of Travel
(Fig 1-7)
5oto15o
Longitudinal
Angle
30oto 60o
Transverse
Angle
Distance from the MIG Torch Nozzle
to the Work Piece
TheelectrodewirestickoutfromtheMIGTorchnoz-
zle should be between 10mm to 20mm. This dis-
tance may vary depending on the type of joint that
is being welded.
Travel Speed
The speed at which the molten pool travels inu-
ences the width of the weld and penetration of the
welding run.
MIG Welding (GMAW) Variables
Mostoftheweldingdonebyallprocessesisoncar-
bon steel. The items below describe the welding vari-
ablesinshort-arcweldingof24gauge(0.024”,0.6mm)
to¼”(6.4mm)mildsheetorplate.Theappliedtech-
niquesandendresultsintheGMAWprocessarecon-
trolled by these variables.
Preselected Variables
Preselected variables depend upon the type of ma-
terial being welded, the thickness of the material, the
welding position, the deposition rate and the me-
chanical properties.
These variables are:
  • Typeofelectrodewire
  • Sizeofelectrodewire
  • Typeofgas
  • Gasowrate
Primary Adjustable Variables
These control the process after preselected variables
have been found. They control the penetration, bead
width, bead height, arc stability, deposition rate
and weld soundness.
Theyare: • ArcVoltage
  • Weldingcurrent(wirefeedspeed)
  • Travelspeed
Secondary Adjustable Variables
These variables cause changes in primary adjustable
variables which in turn cause the desired change in
the bead formation. They are:
1. Stick-Out (distancebetweentheendofthecon-
tact tube (tip) and the end of the electrode wire).
Maintainatabout10mmstick-out
2. Wire Feed Speed. Increase in wire feed speed
increases weld current. Decrease in wire feed speed
decreases weld current.
Electrode Stick-Out
(Fig 1-8)
GasNozzle
Tip to
Work Distance
ContactTip(Tube)
Electrode Wire
Actual
Stick-Out
3. Nozzle Angle. This refers to the position of the
welding gun in relation to the joint. The transverse
angle is usually one half the included angle between
plates forming the joint. The longitudinal angle is the
angle between the centre line of the welding gun
and a line perpendicular to the axis of the weld. The
longitudinal angle is generally called the Nozzle
Angle and can be either trailing (pulling) or lead-
Transverse & Longitudinal
Nozzle Axes (Fig 1-9)
LongitudinalAngle
Transverse Angle
Axis of Weld

15
WT200MP Welding Machine
www.weldtech.net.nz
ing (pushing).Whether the operator is left handed
or right handed has to be considered to realize the
eects of each angle in relation to the direction of
travel.
Nozzle Angle, Right Handed Operator
(Fig 1-10)
Direction of Travel
Leadingor“Pushing”
Angle(ForwardPointing)
Trailingor“Pulling”
Angle(BackwardPointing)
90o
Establishing the Arc and Making Weld Beads
Before attempting to weld on a nished piece of
work, it is recommended that practice welds be
made on a sample metal of the same material as that
of the nished piece.
The easiest welding procedure for the beginner to
experimentwithMIGweldingistheatposition.The
equipment is capable of at, vertical and overhead
positions.
ForpracticingMIGwelding,securesomepiecesof16
or18gauge(1.5mmor2.0mm)mildsteelplate(150
x150mm).Use(0.8mm)uxcoredgaslesswireora
solid wire with shielding gas.
Setting of the Power Source
Power source and Current (Wire Speed) setting re-
quires some practice by the operator, as the welding
plant has two control settings that have to balance.
ThesearetheCurrent(WireSpeed)controlandthe
weldingVoltageControl.
The welding current is determined by the Current
(WireSpeed)control,the current willincrease with
increasedCurrent(WireSpeed),resultinginashorter
arc.LessCurrent(WireSpeed)willreducethecurrent
and lengthen the arc. Increasing the welding voltage
hardly alters the current level, but lengthens the arc.
Bydecreasingthevoltage,ashorterarcisobtained
with a little change in current level.
When changing to a dierent electrode wire dia
eter, dierent control settings are required. A thinner
electrodewireneedsmoreCurrent(WireSpeed)to
achieve the same current level.
A satisfactory weld cannot be obtained if the Current
(WireSpeed)andVoltagesettingsarenotadjustedto
suit the electrode wire diameter and the dimensions
of the work piece.
IftheCurrent(WireSpeed)istoohighfortheweld-
ingvoltage,“stubbing”willoccurasthewiredipsinto
the molten pool and does not melt. Welding in these
conditions normally produces a poor weld due to
lack of fusion. If, however, the welding voltage is too
high, large drops will form on the end of the wire,
causing spatter. The correct setting of voltage and
Current (Wire Speed) can be seen in the shape of
the weld deposit and heard by a smooth regular arc
sound.
Electrode Wire Size Selection
The choice of Electrode wire size and shielding gas
used depends on the following:
 • Thicknessofthemetaltobewelded
 • Typeofjoint
 • Capacityofthewirefeedunitandpowersource
 • Theamountofpenetrationrequired
 • Thedepositionraterequired
 • Thebeadproledesired
 • Thepositionofwelding
 • Costofthewire

16
MIG Welding
Troubleshooting
ThegeneralapproachtoxGasMetalArcWelding
(GMAW)problemsistostartatthewirespoolthen
workthroughtotheMIGtorch.Therearetwomain
areas where problems occur with GMAW, Porosity
and Inconsistent wire feed.
When there is a gas problem the result is usually po-
rosity within the weld metal. Porosity always stems
from some contaminant within the molten weld
pool which is in the process of escaping during so-
lidication of the molten metal.
Contaminants range from no gas around the weld-
ing arc to dirt on the workpiece surface. Porosity can
be reduced by checking the following points.
WARNING!
Disengage the feed roll when testing for gas ow by ear.
Wire feeding problems can be reduced by checking the following points.

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Other weld problems can be reduced by checking the following points.

18
Flat Position,
Down Hand Butt Weld
(Fig 1-11)
Flat Position,
Gravity Fillet Weld
(Fig 1-12)
Horizontal Position,
Butt Weld
(Fig 1-13)
Horizontal-Vertical
(HV) Position
(Fig 1-14)
Vertical Position,
Butt Weld
(Fig 1-15)
Vertical Position,
Fillet Weld
(Fig 1-16)
Overhead Position,
Butt Weld
(Fig 1-17)
Overhead Position,
Fillet Weld
(Fig 1-18)
MMA (Stick) Basic
Welding Guide
Size of Electrodes
The electrode size is determined by the thickness of
metals being joined and can also be governed by
thetypeofweldingmachineavailable.Smallweld-
ingmachineswillonlyprovidecurrent(amperage)to
run smaller sized electrodes.
Forthinsections,itisnecessarytousesmallerelec-
trodes otherwise the arc may burn holes through
the job. A little practice will soon establish the most
suitableelectrode for a given application.
Storage of Electrodes
Always store electrodes in a dry place and in their
original containers.
Electrode Polarity
Electrodes are generally connected to the electrode
holder with the electrode holder connected positive
polarity.
The work lead is connected to the negative polarity
and is connected to the work piece. If in doubt con-
sult the electrode data sheet.
Eects of MMA(Stick) Welding on
Various Materials
High Tensile and Alloy Steels
The two most prominent eects 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underbeadcracksintheweld
area may be reduced by using the correct elec-
trodes, preheating, using higher current settings,
using larger electrodes sizes, short runs for larger
electrode deposits or tempering in a furnace.
Manganese Steels
The eect on manganese steel of slow cooling from
hightemperaturescausesembrittlement.Forthis
reason it is absolutely essential to keep manganese
steelcool 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weld-
able. White iron, because of its extreme brittleness,

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MILD STEEL :
E6011 - This electrode is used for all-position welding or
for welding on rusty, dirty, less-than- new metal. It has
a deep, penetrating arc and is often the rst choice for
repair or maintenance work.
E6013 - This all-position electrode is used for welding
clean, new sheet metal. Its soft arc has minimal spatter,
moderate penetration and an easy-to-clean slag.
E7014 - All positional, ease to use electrode for use on
thicker steel than E6013. Especially suitable for sheet metal
lap joints, llet welds and general purpose plate welding.
E7018 - A low-hydrogen, all-position electrode used when
quality is an issue or for hard-to-weld metals. It has the ca-
pability of producing more uniform weld metal, which has
better impact properties at low temperatures.
CAST IRON:
ENI-CL -Suitableforjoiningallcastironsexceptwhite
cast iron.
STAINLESS STEEL:
E318L-16 -Highcorrosionresistances.Idealfordairy
work etc.
Electrodes for joining dierent metals:
Joint Preparations
In many cases, it will be possible to weld steel sec-
tions without any special preparation. For heavier
Open Square Butt Joint
(Fig 1-19a)
Gapvariesfrom1.6mm(1/16”)
to4.8mm(3/16”)dependingonplatethickness
Single Vee Butt Joint
(Fig 1-19b) Notlessthan45°
Single Vee Butt Joint
(Fig 1-19c) Notlessthan70°
1.6mm(1/16”)max.
1.6mm(1/16”)
Double Vee Butt Joint
(Fig 1-19d) Notlessthan70°
1.6mm(1/16”)max.
1.6mm(1/16”)
Lap Joint (Fig 1-19e)
Fillet Joint (Fig 1-19f)
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.
Types of Electrodes
Arc Welding electrodes are classied into a number
of groups depending on their applications. There are
a great number of electrodes used for specialised in-
dustrial 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 encoun-
tered; are all easy to use.
sections and for repair work on castings, etc., it will
be necessary to cut or grind an angle 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. Typical joint designs
areshowninFigure1-19.

20
Corner Weld
(Fig 1-19g)
Tee Joints
(Fig 1-19h)
Edge Joint
(Fig 1-19i)
Plug Welds
(Fig 1-19j)
Arc Welding Techniques
- A Word for Beginners
Forthosewhohavenotyetdoneanywelding,the
simplest way to commence is to run beads on a piece
ofscrapplate.Usemildsteelplateabout6.0mmthick
and a 3.2mm electrode.
Clean any paint, loose scale or grease o the plate and
set it rmly on the work bench so that welding can
becarriedoutinthedownhandposition.Makesure
thattheWorkLead/Clampismakinggoodelectrical
contact with the work, either directly or through the
work table. For light gauge material, always clamp
the work lead directly to the job, otherwise a poor
circuit will probably result.
The Welder
Place yourself in a comfortable position before be-
ginning to weld. Get a seat of suitable 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 nd that the job becomes much easier.
You can add much to your peace of mind by wearing
a leather apron and gauntlets. You won’t be worry-
ing then about being burnt or sparks setting alight
to your clothes.
Place the work so that the direction of welding is
across, rather than to or from, your body. The elec-
trode holder lead should be clear of any obstruction
so that you can move your arm freely along as the
electrode burns down. If the lead is slung over your
shoulder, it allows greater freedom of movement
andtakesalotofweightoyourhand.Besurethe
insulation on your cable and electrode holder is not
faulty; otherwise you are risking an electric shock.
Striking the Arc
Practice this on a piece of scrap plate before going
on to more exacting work. You may at rst experi-
encedicultyduetothetipoftheelectrode“stick-
ing”totheworkpiece.Thisiscausedbymakingtoo
heavy a contact with the work and failing to with-
draw the electrode quickly enough. A low amper-
age will accentuate it. This freezing-on of the tip may
be overcome by scratching the electrode along the
plate surface in the same way as a match is struck. As
soon as the arc is established, maintain a 1.6mm to
3.2mm gap between the burning electrode end and