Matco Tools MPM141 User manual

INVERTER DC
WIRE FEED WELDER
OWNER’S MANUAL
09/2019
WARNING:
Read carefully and understand all ASSEMBLY AND OPERATION
INSTRUCTIONS before operating. Failure to follow the safety rules and other
basic safety precautions may result in serious personal injury.
1910308-12
MPM141

Page 2 of 20 1910308-12
MATCO TOOLS
EFFECTIVE APRIL 1, 2015
LIMITED WARRANTY
This warranty applies to the original purchaser and is subject to the terms and conditions listed below. This Limited Warranty is for
new equipment sold after the above date, providing coverage for defects in material and workmanship at the time it is shipped from
the factory.
Limited to the warranty periods below, MATCO TOOLS will repair or replace the item under warranty that fails due to defects in
material and workmanship. MATCO TOOLS must be notified within 30 days of the failure, to provide instructions on how to proceed
with the repair of your welder and warranty claim processing. Warranty period begins at the time the welder is purchased from an
Authorized MATCO TOOLS distributor. Keep your receipt as proof of purchase.
Warranty Periods
Limited Warranty is divided into these categories. No Warranty,
1 year, 2 year and 3 year.
No Warranty
Normal wear items, MIG gun parts (contact tips, nozzle, contact
tip adapter, MIG gun liner), drive roll, electrode holder, ground
clamps, and plasma torch parts (nozzle, electrode, diffuser,
cover) are considered consumable items and are not covered
under warranty.
1 Year Accessories Warranty
Parts and Labor on MIG gun parts (except those listed under
normal wear items), cables, regulator, and plasma torch (except
those listed under normal wear items) are covered for 1 year.
Any shipping related to warranty repair is the responsibility of
the customer.
2 Year Welder Warranty
The 2 year warranty covers Parts and Labor on items such as:
transformer, reactor, rectifier, solenoid valve, PC board,
switches, controls, gas valve, drive motor, drive system other
than drive roll and any other component that requires the
removal of the sheet metal to access. Any shipping related to
warranty repair is the responsibility of the customer.
Voiding Warranty
Warranty does not apply to shipping damage, misuse and
abuse of the unit and alteration of the unit in any way.
Warranty Claim
This is a Parts and Labor warranty. Contact the MATCO
TOOLS distributor you purchased the unit from. Retain your
receipt in the case a warranty claim is needed. No warranty will
be provided without the original receipt from an authorized
MATCO TOOLS distributor. To make a warranty claim, contact
your MATCO TOOLS distributor. That MATCO TOOLS
distributor will contact the customer service department for
warranty instructions.
MPM141

GENERAL SAFETY RULES
WARNING: Read and understand all
instructions. Failure to follow all instructions
listed below may result in serious injury or death.
CAUTION: Do not allow persons to
operate or assemble this unit until they have
read this manual and have developed a
thorough understanding of how this unit
works.
WARNING: The warnings, cautions,
and instructions discussed in this
instruction manual cannot cover all possible
conditions or situations that could occur. It
must be understood by the operator that
common sense and caution are factors which
cannot be built into this product but must be
supplied by the operator.
SAVE THESE INSTRUCTIONS
IMPORTANT SAFETY CONSIDERATIONS
1.1 Your Welding Environment
-Keep the environment you will be welding in
free from flammable materials.
-Always keep a fire extinguisher accessible to
your welding environment.
-Always have a qualified person install and
operate this equipment.
-Make sure the area is clean, dry and ventilated.
Do not operate the welder in humid, wet or
poorly ventilated areas.
-Always have your welder maintained by a
qualified technician in accordance with local,
state and national codes.
-Always be aware of your work environment. Be
sure to keep other people, especially children,
away from you while welding.
-Keep harmful arc rays shielded from the view of
others.
-Mount the welder on a secure bench or cart that
will keep the welder secure and prevent it from
tipping over or falling.
1.2 Your Welder’s Condition
-Check ground cable, power cord and welding
cable to be sure the insulation is not damaged.
Always replace or repair damaged components
before using the welder.
-Check all components to ensure they are clean
and in good operating condition before use.
1.3 Use of Your Welder
Do not operate the welder if the output cable,
electrode, torch, wire or wire feed system is wet.
Do not immerse them in water. These
components and the welder must be completely
dry before attempting to use them.
-Follow the instructions in this manual.
-Keep welder in the off position when not in use.
-Connect ground lead as close to the area being
welded as possible to ensure a good ground.
-Do not allow any body part to come in contact
with the welding wire if you are in contact with
the material being welded, ground or electrode
from another welder.
-Do not weld if you are in an awkward position.
Always have a secure stance while welding to
prevent accidents. Wear a safety harness if
working above ground.
-Do not drape cables over or around your body.
-Wear a full coverage helmet with appropriate
shade (see ANSI Z87.1 safety standard) and
safety glasses while welding.
-Wear proper gloves and protective clothing to
prevent your skin from being exposed to hot
metals, UV and IR rays.
-Do not overuse or overheat your welder. Allow
proper cooling time between duty cycles.
-Keep hands and fingers away from moving
parts and stay away from the drive rolls.
-Do not point MIG gun at any body part of
yourself or anyone else.
-Always use this welder in the rated duty cycle
to prevent excessive heat and failure.
1.4 Specific Areas of Danger, Caution or

Page 4 of 20 1910308-12
Warning
Electrical Shock
Electric arc welders can produce a
shock that can cause injury or death.
Touching electrically live parts can cause fatal
shocks and severe burns. While welding, all
metal components connected to the wire are
electrically live. Poor ground connections are a
hazard, so secure the ground lead before
welding.
-Wear dry protective apparel: coat, shirt, gloves
and insulated footwear.
-Insulate yourself from the work piece. Avoid
contacting the work piece or ground.
- Do not attempt to repair or maintain the welder
while the power is on.
-Inspect all cables and cords for any exposed
wire and replace immediately if found.
-Use only recommended replacement cables
and cords.
-Always attach ground clamp to the work piece
or worktable as close to the weld area as
possible.
-Do not touch the welding wire and the ground
or grounded work piece at the same time.
-Do not use a welder to thaw frozen pipes.
Fumes and Gases
-Fumes emitted from the welding
process displace clean air and can
result in injury or death.
-Do not breathe in fumes emitted by the welding
process. Make sure your breathing air is clean
and safe.
-Work only in a well-ventilated area or use a
ventilation device to remove welding fumes from
the environment where you will be working.
-Do not weld on coated materials (galvanized,
cadmium plated or containing zinc, mercury or
barium). They will emit harmful fumes that are
dangerous to breathe. If necessary, use a
ventilator/respirator with air supply or remove
the coating from the material in the weld area.
-The fumes emitted from some metals when
heated are extremely toxic. Refer to the material
safety data sheet for the manufacturer’s
instructions.
-Do not weld near materials that will emit toxic
fumes when heated. Vapors from cleaners,
sprays and degreasers can be highly toxic when
heated.
UV and IR Arc Rays
The welding arc produces ultraviolet
(UV) and infrared (IR) rays that can
cause injury to your eyes and skin. Do not look
at the welding arc without proper eye protection.
-Always use a helmet that covers your full face
from the neck to top of head and to the back of
each ear.
-Use a lens that meets ANSI standards and
safety glasses. For welders under 160 amps
output, use a shade 10 lens; for above 160 amps,
use a shade 12. Refer to the ANSI standard
Z87.1 for more information.
-Cover all bare skin areas exposed to the arc
with protective clothing and shoes. Flame-
retardant cloth or leather shirts, coats, pants or
coveralls are available for protection.
-Use screens or other barriers to protect other
people from the arc rays emitted from your
welding.
-Warn people in your welding area when you are
going to strike an arc so they can
protect themselves.
Fire Hazards
Do not weld on containers or pipes
that contain or have had flammable,
gaseous or liquid combustibles in them. Welding
creates sparks and heat that can ignite
flammable and explosive materials.
-Do not operate an electric arc welder in areas
where flammable or explosive materials are
present.
-Remove all flammable materials within 35 feet
of the welding arc. If removal is not possible,
tightly cover them with fireproof covers.
-Take precautions to ensure that flying sparks do
not cause fires or explosions in hidden areas,
cracks or areas you cannot see.

Page 5 of 20 1910308-12
-Keep a fire extinguisher close in the case of fire.
-Wear garments that are oil-free with no pockets
or cuffs that will collect sparks.
-Do not have on your person any items that are
combustible, such as lighters or matches.
-Keep work lead connected as close to the weld
area as possible to prevent any unknown,
unintended paths of electrical current from
causing electrical shock and fire hazards.
-To prevent any unintended arcs, cut wire back
to stick out ¼" after welding.
Hot Materials
Welded materials are hot and can
cause severe burns if handled
improperly.
-Do not touch welded materials with bare hands.
-Do not touch MIG gun nozzle after welding until
it has had time to cool down.
Sparks/Flying Debris
Welding creates hot sparks that can
cause injury. Chipping slag off welds creates
flying debris.
-Always wear protective apparel: ANSI-
approved safety glasses or shield, welder’s hat
and ear plugs to keep sparks out of ears and
hair.
Electromagnetic Field
-Electromagnetic fields can interfere
with various electrical and electronic
devices such as pacemakers.
-Consult your doctor before using any electric
arc welder or cutting device.
-Keep people with pacemakers away from your
welding area when welding.
-Do not wrap cable around your body while
welding.
-Wrap MIG gun and ground cable together
whenever possible.
-Keep MIG gun and ground cables on the same
side of your body.
Shielding Gas Cylinders Can
Explode
High pressure cylinders can explode if
damaged, so treat them carefully.
-Never expose cylinders to high heat, sparks,
open flames, mechanical shocks or arcs.
-Do not touch cylinder with MIG gun.
-Do not weld on the cylinder.
-Always secure cylinder upright to a cart or
stationary object.
-Keep cylinders away from welding or electrical
circuits.
-Use the proper regulators, gas hose and fittings
for the specific application.
-Do not look into the valve when opening it.
-Use protective cylinder cap whenever possible.
1.5 Proper Care, Maintenance and Repair
-Always have power disconnected when
working on internal components.
- Do not touch or handle PC board without being
properly grounded with a wrist strap. Put PC
board in static proof bag to move or ship.
-Do not put hands or fingers near moving parts
such as drive rolls or fan.
WARNING
Breathing welding fumes exposes you to
chemicals, including chromium (hexavalent
compounds), known to the State of California
to cause cancer and birth defects or other
reproductive harm. *Always weld in a well-
ventilated area. * If in an enclosed area, vent
the exhaust to the outside. For more
information go to www.P65warings.ca.gov.
WARNING
This product can expose you to chemicals
including Lead, which is known to the State
of California to cause cancer and birth
defects or other reproductive harm. For
more information go to
www.P65warings.ca.gov.

Page 6 of 20 1910308-12
USE AND CARE
•Do not modify this unit in any way.
Unauthorized modification may impair the
function and/or safety and could affect the
life of the equipment. There are specific
applications for which this unit was
designed.
•Always check for damaged or worn out
parts before using this unit. Broken parts
will affect the operation. Replace or repair
damaged or worn parts immediately.
•Store idle. When this unit is not in use,
store it in a secure place out of the reach of
children. Inspect it for good working
condition prior to storage and before re-
use.
TECHNICAL SPECIFICATIONS
Item
Description
Power Supply
120V, 20A, 60 HZ, Single Phase
No-Load Voltage
60 Volts DC
Output Range
30 - 90 Amp DC
Duty Cycle
30% @ 90A
Suggested Wire
MIG: Steel, Stainless, Flux Core: Steel
Wire Diameter
.023 - .035
Dimensions
14.4" x 6" x 11.4"
Weight
16.9 lbs.
DESCRIPTION
The Matco Tools MPM141 is a portable DC wire feed welder capable of welding with solid wire (with
shielding gas) or flux core wire. It uses leading edge Inverter Technology to provide high quality welds
that are crisp, clean, and consistent with plenty of power and will impress the most experienced of
welders. It is powered by AC single phase 120V (110-120V), 60HZ/20amp with time delayed fuse or
circuit breaker. It features infinite wire feed speed control and voltage control giving you total control
to tune in the arc you want. The MPM141 also features a cooling fan, power, thermal overload
protection (alarm), and work lights to help protect your investment. The Inverter Technology is evident
from the moment you take this unit out of the box. One of the many advantages of inverter technology
is creating more welding power from a smaller transformer. A smaller transformer means lower overall
weight. The MPM141 is ideal for use when welding materials from 22 gauge to 1/8” and is ideal for
the home hobbyist, auto repair, farm and ranch and light industrial applications.

Page 7 of 20 1910308-12
POWER INDICATOR LIGHT
In the “OFF” position, no power is being supplied
to the torch. In the “ON” position, power is
supplied to the main transformer and control
circuit.
ALARM INDICATOR LIGHT
If the duty cycle of the welder is exceeded, the
internal temperature will exceed safe
temperatures and the machine will shut down.
The thermal overload light will come on indicating
this. Leave the unit on and allow 15 minutes for
cool down before the light will go off and the
temperature to fall into an allowable operating
range.
WORK LIGHT
This means the machine is working and the
machine is welding and under load.
WIRE FEED SPEED CONTROL
Adjustment of the wire feed speed. Refer to the
"set up" chart inside the wire feed compartment
for initial adjustment settings.
WELDING VOLTAGE CONTROL
The voltage control is on the front panel of
machine. Refer to the “set up” chart inside the
wire feed compartment for initial adjustment
settings.
GROUND CABLE AND CLAMP
The ground cable and clamp are attached to the
work piece to complete the circuit allowing the
flow of current needed to weld.
MIG TORCH
The welding wire is driven through the welding
cable and torch to the work piece. It is attached to
the drive system. The trigger activates the drive
motor.
INERT GAS REGULATOR AND HOSE
The Inert Gas Regulator installs on the shielding
gas cylinder for MIG welding with solid wires. The
regulator controls compressed gas and allows
adjustment flow rate of the gas. The gas hose
connects to the regulator/flow gauge and delivers
the shielding gas from the shielding gas bottle to
the welder.
POWER CORD AND PLUG
Plug this unit into a 120V, 20-amp circuit
breaker power supply.
FLUX CORE NOZZLE AND CONTACT TIPS
The flux core nozzle is used during flux core
Welding
Voltage Control
Ground Cable
And Clamp
MIG
Torch
Power
Indicator
Wire Feed
Speed Control
Work
Light
Inert Gas
Hose
Inert Gas
Regulator
Flux Core Nozzle and
Contact Tips
Alarm
Light
Power
Cord

Page 8 of 20 1910308-12
welding. It protects the contact tip adapter from
spatter and debris during the flux core welding
process. The extra contact tips are **Tweco® 11-
30 style tips used when using .030 welding wire.
**Tweco is a registered trademark of Victor Technologies
International, Inc.
INSTALLATION
1. POWER REQUIREMENT - AC single phase
120V (110-120V) 60 HZ fused with a 20-amp
time delayed fuse or circuit breaker is required.
DO NOT OPERATE THIS UNIT if the ACTUAL
power source voltage is less than 105 volts AC
or greater than 132 volts AC.
Electrical Shock
•High voltage danger from power source!
Consult a qualified electrician for proper
installation of receptacle. This welder
must be grounded while in use to
protect the operator from electrical
shock.
•Do not remove grounding prong or alter
the plug in any way. Do not use any
adapters between the welder's power
cord and the power source receptacle.
Make sure the POWER switch is OFF
when connecting your welder's power
cord to a properly grounded 120 VAC, 60
HZ, Single Phase, 20 Amp input power
supply.
2. EXTENSION CORD - We do not recommend
an extension cord because of the voltage drop
they produce. This drop, in voltage, can affect
the performance of the welder. If you need to
use an extension cord, it must be a size #12 or
larger. Check with a qualified electrician and
your local electrical codes for your specific
area. Do not use an extension cord over 25 ft.
in length.
3. INSTALL THE WIRE ROLLER - The wire
roller has been factory installed. However,
check to make certain the correct wire groove
is in place to accommodate the size of wire you
are using. Open the wire feed compartment.
Adjust the drive roller according to the following
steps, see following picture about the wire
feeder structure:
3.1 Open the door to the welder drive
compartment.
3.2 Remove the drive tension by
loosening the drive tension adjusting knob
(1) and lifting the Drive Tension Adjustor
away from the Drive Tension Arm (2). Lift
the Drive Tension Arm away from the Drive
Roller (3).
3.3 If there is wire already installed in the
welder, roll it back onto the wire spool by
hand-turning the spool clockwise. Be
careful to hold onto the wire while rolling it
back, if you let go of the wire when it
reaches the end of the inlet guide, the wire
will unspool itself. Put the end of the wire
into the hole on the outside edge of the
wire spool and bend it over to hold the wire
in place. Remove the spool of wire from
the drive compartment of the welder.
3.4 Rotate the Drive Roller Cap (3)
counterclockwise and remove it from the
Drive Roller.
3.5 Pull the Drive Roller off the Drive
Roller shaft.
3.6 Based on the wire diameter, select the
correct groove. When installing the drive
roller, the number stamped on the drive
roller for the wire size you are using should
be facing you. Push the Drive Roller onto
the Drive Roller Shaft.
3.7 Reinstall the Drive Roller Cap and
lock in place by turning it clockwise.
3.8 Close the door to the welder drive
compartment.

Page 9 of 20 1910308-12
4. INSTALL THE WIRE
4.1 Select welding wire - We recommend
the usage of .030 wire on this unit.
However, .023 - .035 wire may be used.
Both four-inch and eight-inch wire spools
can be used on this welder.
NOTE:
- Metal thinner than 24 gauge cannot be
welded with this machine. Attempting to do so
will cause burn through in the metal you are
intending to weld.
- Do not use rusty wire. Remove any wire that
is rusty. If the whole spool is rusty, discard it
and use another roll.
4.2 Installing the wire
Electrical Shock
•Electric shock can kill! Always turn the
POWER switch OFF and unplug the
power cord from the AC power source
before installing wire.
NOTE:
- Before installing, make sure that you have
removed any old wire from the torch assembly.
This will help to prevent the possibility of the
wire jamming inside the gun liner.
- Be very careful when removing the welding
nozzle. The contact tip on this welder is live
whenever the torch trigger is pulled. Make
certain POWER is turned OFF.
4.2.1 Remove the nozzle and contact
tip from the end of the torch assembly.
4.2.2 Make sure the proper groove on
the drive roller is in place for the wire
installed. If not, change the drive roller
as described in Section 3.
4.2.3 Remove the packaging from the
spool of wire and then identify the
leading end of the wire secured on the
edge of the spool. DO NOT UNHOOK
IT AT THIS TIME.
4.2.4 Place the spool on the spool hub
so the wire will pull off the bottom of
the spool. The welding wire should
always come off the bottom of the
spool into the drive mechanism. See
following figure.
MIG
Nozzle
Flux Core
Nozzle
Contact
Tip

Page 10 of 20 1910308-12
4.2.5 The welder can use either 4-
or 8-inch spools. See the following
figure for additional reference. The
wing nut controls the tension on the
spool.
4.2.6 Setting the wire spool
tension. a) Turn the spool of wire with
one hand. b) Increase the spool
tension by tightening (turn clockwise)
the wing nut while turning the spool.
Turn the spool while tightening the
wing nut until the spool slows down
and you feel a slight drag. Stop
tightening the wing nut, you may need
to repeat these steps until proper
spool tension is achieved.
NOTE:
- If TOO MUCH tension is applied to the wire
spool, the wire will slip on the drive roller or will
not be able to feed at all. If TOO LITTLE
tension is applied, the spool of wire will want to
unspool itself when the trigger is released.
Readjust the spool tension using the wing nut
as necessary to correct for either problem.
4.2.7 With the welder disconnected
from the power source, remove the
leading end of the wire from the spool.
Hold on to it securely, to avoid
unspooling or tangling of the wire as it
will result in tangled wire and feeding
problems.
4.2.8 Cut off any bent portion of
the wire using a wire cutter.
4.2.9 Loosen the tension adjusting
knob holding the drive tension arm in
place and lift the tension arm up off
the drive roller.
4.2.10 Insert the wire into the inlet
guide tube, feed it across the drive
roller and into the torch assembly
about six inches.
-Make certain that the welding wire is going into
the torch liner. If not, the wire will jam up in the
mechanism.
4.2.11 Line the wire up with the
correct groove in the drive roller. Place
the drive tension arm back above the
drive roller.
4.2.12 Place the drive tension
adjustment arm back in place.
4.2.13 Tighten (turn clockwise) the
drive tension adjusting knob until the
tension roller is applying enough force
on the wire to prevent it from slipping
in the drive rollers. DO NOT OVER
TIGHTEN.
8 Inch
4 Inch

Page 11 of 20 1910308-12
4.2.14 NOW YOU CAN LET GO OF
THE WIRE.
4.2.15 Plug in the welder power
cord and turn the welder ON. Set the
Voltage switch to the voltage setting
recommended for the gauge metal
that is to be welded. Refer to the set-
up chart on the back side of the drive
compartment door.
-The welding wire is electrically hot when the
power is on and the torch trigger is activated.
4.2.16 Set the WIRE SPEED control
to the middle of the wire speed range.
4.2.17 Straighten the MIG torch
cable and pull the trigger in the gun
handle to feed the wire through the
torch assembly. When at least one
inch of the wire sticks out past the end
of the torch, release the trigger.
4.2.18 Turn the Power Switch to the
OFF position.
4.2.19 Select a contact tip stamped
with the same diameter as the wire
being used.
NOTE:
- Due to inherent variances in flux cored
welding wire, it may be necessary to use a
contact tip one size larger when welding with
flux core wire if wire jams occur.
4.2.20 Slide the contact tip over the
wire (protruding from the end of the
torch). Thread the contact tip into the
end of the torch and hand-tighten
securely.
4.2.21 Install the nozzle on the torch
assembly.
4.2.22 Cut off excess wire that
extends past the end of the nozzle
more than 1/4 inch.
4.2.23 Turn the welder ON.
5. SETTING THE DRIVE ROLL TENSION
Arc flash can injure eyes! To reduce the risk
of arc flash, make certain that the wire
coming out of the end of the torch does not
come in contact with the work piece, ground
clamp, or any grounded material during the
drive tension setting process or arcing will
occur.
5.1 Press the trigger on the torch.
5.2 Turn the drive tension adjustment
knob clockwise until the wire seems to feed
smoothly without slipping.
6. GAS INSTALLATION
Shielding gas cylinders and high-pressure
cylinders can explode if damaged, so treat
them carefully.
•Never expose cylinders to high heat,
sparks, open flames, mechanical shocks
or arcs.
•Do not weld on the cylinder.
•Always secure cylinder upright to a cart
or stationary object.
•Keep cylinders away from welding or
electrical circuits.
•Use the proper regulators, gas hose and
fittings for the specific application.
6.1 Polarity Changing - When MIG wire is
used, shielding
gas is required
and the polarity
on this unit
needs to be
electrode
positive.
6.1.1 Electrode Positive for MIG
Welding - The Weld Power Cable
should be connected to the positive (+)
weld output connection on the front of
the machine. The ground cable would
then be connected to the negative (-)
weld output connection.
6.1.2 Electrode Negative for Flux Core
Welding - The Weld Power Cable should
be connected to the negative (-) weld
output connection on the front of the
machine. The ground cable would then be
connected to the positive (+) weld output

Page 12 of 20 1910308-12
connection. Refer to the polarity setting
label inside the wire compartment.
6.2 Connect one end of the gas hose to
the gas hose connection on the back of the
welder.
6.3 Connect the other end of the gas hose
to the gas hose connection on the supplied
regulator/flow gauge.
6.4 Before installing the regulator, it is
then be connected to the positive (+) weld
output connection. Refer to the polarity
setting label inside the wire compartment.
(1) Gas Bottle Valve
(2) Gas Flow Gauge (Set at 20 CFH)
(3) Gas Pressure Gauge
(4) Regulator
(5) Gas Flow Adjuster
(6) Gas Hose Connection
(7) Gas Cylinder
6.5 Open the Gas Bottle Valve on the
cylinder of gas.
6.6 Turn the Gas Flow Adjuster on the
regulator so that the gas flow rate is set at
approximately 20 CFH. Make certain you
are reading the correct scale on the gauge.
NOTE: Slowly open the cylinder valve by
turning it counterclockwise until the cylinder
pressure gauge registers on the first gauge of
the regulator. Turn the adjustment knob
clockwise (right) slowly to increase gas flow to
20 CFH. To reduce the gas flow, turn the
adjustment counterclockwise (left). The gas
valve is located on the back panel of the welder
and activated by the trigger. Gas flow should be
heard when the trigger is activated. No gas flow
will result in a harsh arc with excessive spatter,
a smooth weld bead will be difficult to obtain.
Avoid unnecessary gas loss by closing the tank
valve when finished welding.
6.7 Gas selection
Different materials require different
shielding gas when MIG welding, refer to
the set-up chart inside the wire feed
compartment.
Mild steel: Use 75% Argon and 25% CO2
for reduced spatter and reduced
penetration for thinner materials. Do NOT
USE Argon gas concentrations higher than
75% on steel. The result will be extremely
poor penetration, porosity, and brittleness
of weld.
Mild Steel: Use CO2 for deeper
penetration but increased spatter. (A CO2
regulator adapter will be needed)
Stainless steel: Use a mixed gas
consisting of Helium, Argon and CO2.
Aluminum or bronze: Use 100% Argon.
OPERATION
High voltage danger from power source!
Consult a qualified electrician for proper
installation of receptacle at the power
source. This welder must be grounded while
in use to protect the operator from electrical
shock. If you are not sure if your outlet is
properly grounded, have it checked by a
qualified electrician. Do not cut off the
grounding prong or alter the plug in any
way and do not use any adapter between
the welder's power cord and the power
source receptacle. Make sure the POWER
switch is OFF then connecting your
welder's power cord to a properly grounded
115 VAC (110V - 120V), 60 HZ, single phase,
20-amp power source.

Page 13 of 20 1910308-12
1. POWER SWITCH
The power switch supplies electrical current to
the welder. Whenever the power switch is in the
ON position, the welding circuit is activated.
ALWAYS turn the power switch to the OFF
position and unplug the welder before
performing any maintenance.
2. VOLTAGE SELECTOR
The voltage selector controls the welding
voltage/heat. This unit has a voltage control
that is infinitely adjustable within its range.
Refer to the label inside the welder side door
for recommended voltage selector settings for
your welding job.
3. WIRE SPEED CONTROL
The wire speed control adjusts the speed at
which the wire is fed out of the welding torch.
The wire speed needs to be closely matched
(tuned-in) to the rate at which it is being melted
off. Some things that affect wire speed
selection are the type and diameter of the wire
being used, the heat setting selected, and the
welding position being used. Refer to the label
inside the welder side door for recommended
wire speed settings for your welding job.
NOTE: The wire will feed faster without an arc.
When an arc is being drawn, the wire speed will
slow down.
4. HOLDING THE TORCH
The best way to hold the welding torch is the
way it feels most comfortable to you. While
practicing with your new welder, experiment by
holding the torch in different positions until you
find the one that seems to work best for you.
5. POSITION OF THE TORCH TO THE WORK
PIECE
There are two angles of the torch nozzle in
relation to the work piece that must be
considered when welding.
5.1. Angle can vary, but in most cases the
optimum angle will be 60 degrees, the
point at which the torch angle is parallel to
the work piece. If angle A is increased,
penetration will increase. If angle A is
decreased, penetration will decrease also.
5.2. Angle B can be varied for two reasons:
to improve the availability to see the arc in
relation to the weld puddle and to direct
the force of the arc.
6. DISTANCE FROM THE WORK PIECE - If
the nozzle is held off the work piece, the
distance between the nozzle and the work
piece should be kept constant and should not
exceed 1/4 inch or the arc may begin
sputtering, signaling a loss in welding
performance.
7. TUNING IN THE WIRE SPEED - This is one
of the most important parts of wire welder
operation and must be done before starting
each welding job or whenever the voltage
setting, or wire diameter is changed.
EXPOSURE TO A WELDING ARC IS
EXTREMELY HARMFUL TO THE EYES AND
SKIN! Prolonged exposure to the welding
arc can cause blindness and burns. Never
strike an arc or begin welding until you are
adequately protected. Wear flame-proof
welding gloves, a heavy long-sleeved shirt,
trousers without cuffs, high topped shoes,
and an ANSI approved welding helmet.
7.1 Connect the Ground Clamp to a scrap
piece of the same type of material which

Page 14 of 20 1910308-12
you will be welding. It should be equal to or
greater than the thickness of the actual
work piece, and free of oil, paint, rust, etc.
7.2 Select a heat setting.
7.3 Hold the torch in one hand. Hold the
wire just off the work piece. (See
HOLDING THE TORCH section if you are
uncertain of the angle at which you will be
welding.)
7.4 Set the wire feed speed based on the
thickness of material and the set-up chart
on the back side of the wire feeder door.
7.5 Lower your welding helmet. Pull the
trigger on the torch and let the wire feed
into the work piece to start an arc. Then
begin to drag the torch toward you.
7.6 LISTEN! If the arc is sputtering,
increase the wire speed slightly and try
again. Continue increasing the wire speed
adjustment until you achieve a smooth
buzzing sound. If the wire seems to
"pound" into the work piece, decrease wire
speed slightly and try again. Use the wire
speed control to slightly increase or
decrease the heat and penetration for a
given voltage setting by increasing or
decreasing the wire speed slightly. Repeat
this tune-in procedure if you select a new
voltage setting, a different wire diameter,
or a different roll of wire.
8. WELDING TECHNIQUES
EXPOSURE TO A WELDING ARC IS
EXTREMELY HARMFUL TO THE EYES AND
SKIN! Prolonged exposure to the welding
arc can cause blindness and burns. Never
strike an arc or begin welding until you are
adequately protected. Wear flame-proof
welding gloves, a heavy long-sleeved shirt,
trousers without cuffs, high topped shoes,
and an ANSI approved welding helmet.
ELECTRIC SHOCK CAN CAUSE INJURY OR
DEATH! To prevent ELECTRIC SHOCK, do
not perform any welding while standing,
kneeling, or lying directly on the grounded
workpiece.
8.1 Moving the torch
Torch travel refers to the movement of the
torch along the weld joint and is broken
into two elements: Direction and Speed. A
solid weld bead requires that the welding
torch be moved steadily and at the right
speed along the weld joint. Moving the
torch too fast, too slow, or erratically will
prevent proper fusion or create a lumpy,
uneven bead. Travel direction is the
direction the torch is moved along the weld
joint in relation to the weld puddle. The
torch is either PUSHED into the weld
puddle or PULLED away from the weld
puddle.
For most welding jobs you will pull the
torch along the weld joint to take
advantage of the greater weld puddle
visibility. Travel speed is the rate at which
the torch is being pushed or pulled along
the weld joint. For a fixed heat setting, the
faster the travel speed, the lower the
penetration and the lower and narrower
the finished weld bead, likewise, the
slower the travel speed, the deeper the
penetration and the higher and wider the
finished weld bead. As a good rule of
thumb, the thickness of a cross-section of
the weld bead should be approximately the
same thickness as the thinnest material
you are welding.
8.2 Types of welding beads
As you become more familiar with your
new welder and better at laying some
simple weld beads, you can begin to try
some different weld bead types.

Page 15 of 20 1910308-12
The STRINGER BEAD is formed by
traveling with the torch in a straight line
while keeping the wire and nozzle
centered over the weld joint. See following
figure.
The WEAVE BEAD used when you want to
deposit metal over a wider space than would be
possible with a stringer bead. It is made by
weaving from side to side while moving with the
torch. It is best to hesitate momentarily at each
side before weaving back the other way.
8.3 Welding position
FLAT POSITION is easiest of the welding
positions and is most commonly used. It is
best if you can weld in the flat position if
possible, as good results are easier to
achieve.
HORIZONTAL POSITION is performed
very similarly to the flat weld except that
angle B (see HOLDING THE TORCH) is
such that the wire, directed more toward
the metal above the weld joint is to help
prevent the weld puddle from running
downward while still allowing slow enough
travel speed. A good starting point for
angle B is about 30 degrees DOWN from
being perpendicular to the work piece.
VERTICAL POSITION It is easier for many
people to pull the torch from top to bottom.
It can be difficult to prevent the puddle
from running downward. Pushing the torch
from bottom to top may provide better
puddle control and allow slower rates of
travel speed to achieve deeper
penetration. When vertical welding, angle
B (see HOLDING THE TORCH) is usually
always kept at zero, but angle A will
generally range from 45 to 60 degrees to
provide better puddle control.
OVERHEAD POSITION is the most
difficult welding position. Angle A (see
HOLDING THE TORCH) should be
maintained at 60 degrees. Maintaining this
angle will reduce the chances of molten
metal falling into the nozzle. Angle B
should be held at zero degrees so that the
wire is aiming directly into the weld joint. If
you experience excessive dripping of the
weld puddle, select a lower heat setting.
Also, the weave bead tends to work better
than the stringer.

Page 16 of 20 1910308-12
8.4 Multiple pass welding
Butt Weld Joints: When butt welding
thicker materials; you will need to prepare
the edges of the material to be joined by
grinding a bevel on the edge of one or both
pieces of the metal being joined. When this
is done, a “V” is created between the two
pieces of metal that will have to be welded
closed. In most cases, more than one pass
or bead will need to be laid into the joint to
close the “V.” Laying more than one bead
into the same weld joint is known as a
multiple-pass weld. The illustrations in
following figure show the sequence for
laying multiple pass beads into a single “V”
butt joint.
NOTE:
WHEN USING SELF-SHIELDING FLUX-CORE
WIRE it is very important to thoroughly chip and
brush the slag off each completed weld bead
before making another pass or the next pass
will be of poor quality.
Fillet Weld Joints. Most fillet weld joints,
on metals of moderate to heavy thickness,
will require multiple pass welds to produce
a strong joint. The following figure will
show the sequence of laying multiple pass
beads into a T fillet joint and a lap fillet
joint.
8.5 Spot welding
There are three methods of spot welding:
Burn-Through, Punch and Fill, and Lap.
Each has advantages and disadvantages
depending on the specific application as
well as personal preference.
8.5.1. The BURN-THROUGH
METHOD welds two overlapped
pieces of metal together by burning
through the top piece and into the
bottom piece. With the burn-through
method, larger wire diameters tend to
work better than smaller diameters.
Wire diameters that tend to work best,
with the burn-through method are
0.035-inch self-shielding flux-core
wire. Do not use 0.030-inch self-
shielding flux core wires when using
the burn-through method unless the
metal is VERY thin or excessive filler

Page 17 of 20 1910308-12
metal build-up and minimal
penetration is acceptable. Always
select the HIGH heat setting with the
burn-through method and tune in the
wire speed prior to making a spot
weld.
8.5.2. The PUNCH AND FILL
METHOD produces a weld with the
most finished appearance of the three
spot weld methods. In this method, a
hole is punched or drilled into the top
piece of metal and the arc is directed
through the hole to penetrate the
bottom piece. The puddle can fill up
the hole leaving a spot weld that is
smooth and flush with the surface of
the top piece. Select the wire
diameter, heat setting, and tune in the
wire speed as if you were welding the
same thickness material with a
continuous bead.
8.5.3. The LAP SPOT METHOD
directs the welding arc to penetrate
the bottom and top pieces, at the
same time, right along each side of
the lap joint seam. Select the wire
diameter, heat setting, and tune in the
wire speed as if you were welding the
same thickness material with a
continuous bead.
8.6 SPOT WELDING INSTRUCTIONS
8.6.1. Select the wire diameter and
heat setting recommended above for
the method of spot welding you intend
to use.
8.6.2. Tune in the wire speed as if you
were going to make a continuous weld.
8.6.3. Hold the nozzle piece completely
perpendicular to and about 1/4 inch off the work
piece.
8.6.4. Pull the trigger on the torch and
release it when it appears that the desired
penetration has been achieved.
8.6.5. Make practice spot welds on scrap
metal, varying the length of time you hold
the trigger, until a desired spot weld is
made.
8.6.6. Make spot welds on the actual work
piece at desired locations.

Page 18 of 20 1910308-12
MAINTENANCE
•Maintain your welder. It is recommended that the general condition of any welder be examined
before it is used. Keep your welder in good repair by adopting a program of conscientious repair
and maintenance. Have necessary repairs made by qualified service personnel.
•Periodically clean dust, dirt, grease, etc. from your welder.
•Every six months, or as necessary, remove the cover panel from the welder and air-blow any
dust and dirt that may have accumulated inside the welder.
•Replace power cord, ground cable, ground clamp, or electrode assembly when damaged
or worn.
TROUBLESHOOTING
SYMPTOM
POSSIBLE CAUSE
CORRECTIVE ACTION
Unit Does Not Power Up
Unit Is Not Plugged In
Plug in Unit
Input Power Circuit Breaker Not On
Reset Input Power Circuit Breaker
The Main Power Switch Is Not Working
Replace Main Power Switch
Wire Drive Motor Does Not Turn
Loose or Bad Fuse
Locate the Fuse Holder inside the wire
compartment. Tighten fuse or replace.
Wire Feed Speed Control at Zero
Increase Wire Feed Speed Control
Trigger Is Not Mashed
Wire Will Feed Only When Trigger Is
Mashed
Wire Drive Motor Is Damaged
Replace Wire Drive Motor
Overload Indicator is on
Input Voltage is too high or too low
Meter Input Power Voltage. This unit
must be used with input voltage that
ranges from 220V-240V AC (105V-132V
when operating using the 120V adapter
cord).
Welder is overheated
Leave the power on. Allow the fan to cool
the welder until the overload indicator
light is off.
Wire Feeds Inconsistently
Torch Liner is plugged
Clear or replace torch liner
Wire Diameter may vary on spool of wire
causing the wire to catch in the contact
tip.
Increase the contact tip one size.
Too Much or Too Little Wire Tension
See Installing the Wire Section
Too Much or Too Little Drive Roll Tension
See Setting Drive Roll Tension Section
Drive Roll is Worn
Replace Drive Roll
Can Not Create an Arc
Work Piece is Painted or Rusty
Remove All Paint and Rust
Ground Clamp Is Connected Where
There Is Paint or Rust
Remove All Paint and Rust So Ground
Clamp Is Connected to Bare Metal
Ground Clamp Is Not Electrically
Connected to The Work Piece
Make Certain the Ground Clamp Is
Connected to The Work Piece
Trigger Is Not Pressed
This Unit Is Not Electrically Hot Until You
Press the Torch Trigger
For Assistance, call 855-920-2399

Page 19 of 20 1910308-12
DIAGRAM & PARTS LIST
REFERENCE
PART NUMBER
DESCRIPTION
QTY
1
165200032
HANDLE
1
2
165200026
ENCLOSURE
1
3
165200049
MIDDLE BOARD
1
4
165200050
MAIN CONTROL BOARD
1
5
165200002
FRONT PLASTIC PANEL
1
6
105200448
CONTROL PC BOARD
1
7
105200063
POTENTIOMETER KNOB
2
8
155200087
SUPPORT BOARD
1
9
105200199
GROUND CABLE
1
10
105200063
NOZZLE
1
11
105200043
CONTACT TIP
1
12
105200237
MIG TORCH
1
13
105200054
BASE PLATE
1
14
105200198
WIRE FEEDER
1
15
105200241
BINDING POST (BLACK)
1
16
105200242
BINDING POST (RED)
1
17
165200027
DOOR
1
18
105200009
SPOOL HOLDER ASSEMBLY
1
19
105200080
LATCH
1
20
125200077
FAN
1
21
165200051
FAN SUPPORT
1
22
165200016
BACK PLASTIC PANEL
1
23
105200441
GAS CONNECTOR
1
24
105200266
GAS HOLDER
1
25
105800002
POWER CORD
1
26
105200046
SWITCH
1
Replacement parts can be ordered through your Matco Tools Distributor
For technical questions, call 855-920-2399.

Page 20 of 20 1910308-12
Distributed by
Matco Tool
4403 Allen Road
Stow OH 44224
ww w . m a t c o t o o l s . c o m
Made in China