PROCRAFT 511307 User manual

MIG / MAG
MODELS 511307, 511467 & 511625
WELDING
SAVE THIS MANUAL
WARNING!
READ AND UNDERSTAND ALL INSTRUCTIONS
Failure to follow all instructions listed below may result
in electric shock, re, and/or serious injury.
SAVE THESE INSTRUCTIONS
Keep this manual for the safety warnings and precautions,
assembly, operating, inspection, maintenance and
cleaning procedures. Write the product’s serial number
in the back of the manual (or month and year of purchase
if product has no number). Keep this manual and the
receipt in a safe and dry place for future reference.
OPERATING INSTRUCTIONS
PROCRAFT

Page 2
FIG.1
511307: 170i Multi MIG / MMA / TIG
FIG.2
511467: 210i Multi MIG / MMA / TIG

Page 3
FIG.1
511625: 250i MIG / MAG

Page 4



SAVE THIS MANUAL
Keep this manual for the safety
warnings and precautions, assembly,
operating, inspection, maintenance and
cleaning procedures. Write the product’s
serial number in the back of the manual
near the assembly diagram (or month and
year of purchase if product has no
number). Keep this manual and the receipt
in a safe and dry place for future
reference.
IMPROTANT SAFETY INFORMATION
In this manual, on the labeling, and all
other information provided with this
product:
This is the safety alert symbol. It is
used to alert you to potential personal
injury hazards. Obey all safety
messages that follow this symbol to
avoid possible injury or death.
DANGER indicates a hazardous
situation which, if not avoided, will
result in death or serious injury.
WARNING: WARNING indicates a
hazardous situation which, if not
avoided, could result in death or
serious injury.
CAUTION: CAUTION, used with
the safety alert symbol, indicates a
hazardous situation which, if not
avoided, could result in minor or
moderate injury.
NOTICE: NOTICE is used to
address practices not related to
personal injury.
SAFETY WARNINGS AND
PRECAUTIONS
WARNING: When using tool, basic safety
precautions should always be followed to
reduce the risk of personal injury and
damage to equipment.
Read all instructions before using this
tool!
Work Area Precautions
1. Keep your work area clean and well
lit. Cluttered benches and dark areas
invite accidents.
2. Do not operate power tools in
explosive atmospheres, such as in
the presence of flammable liquids,
gases, or dust. Power tools create
sparks which may ignite the dust or
fumes.
3. Keep bystanders, children, and
visitors away while operating a
power tool. Distractions can cause
you to lose control. Protect others in
the work area from debris such as
chips and sparks. Provide barriers or
shields as needed.
WARNING!

READANDUNDERSTANDALL
INSTRUCTIONS
Failuretofollowallinstructionslistedbelow
mayresultinelectricshock,fire,and/or
seriousinjury.
SAVETHESEINSTRUCTIONS

Page 5
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
Electrical Safety
1. Grounded tools must be plugged
into an outlet properly installed and
grounded in accordance with all
codes and ordinances. Never
remove the grounding prong or
modify the plug in any way. Do not
use any adapter plugs. Check with
a qualified electrician if you are in
doubt whether the outlet is properly
grounded. If the tool should
electrically malfunction or break down,
grounding provides a low resistance
path to carry electricity away from the
user.
2. Double insulated tools are
equipped with a polarized plug (one
blade is wider than the other). This
plug will fit in a polarized outlet
only one way. If the plug does not
fit fully in the outlet, reverse the
plug. If it still does not fit, contact a
qualified electrician to install a
polarized outlet. Do not change the
plug in any way. Double insulation
eliminates the need for the three wire
grounded power cord and grounded
power supply system.
3. Avoid body contact with grounded
surfaces such as pipes, radiators,
ranges, and refrigerators. There is
an increased risk of electric shock if
your body is grounded.
4. Do not expose power tools to rain
or wet conditions. Water entering a
power tool will increase the risk of
electric shock.
5. Do not abuse the Power Cord.
Never use the Power Cord to carry
the tool or pull the Plug from an
outlet. Keep the Power Cord away
from heat, oil, sharp edges, or
moving parts. Replace damaged
Power Cords immediately.
Damaged Power Cords increase the
risk of electric shock.
6. When operating a power tool
outside, sue an outdoor extension
cord marker “W-A” or “W”. These
extension cords are rated for outdoor
use, and reduce the risk of electric
shock.
Personal Safety
1. Stay alert. Watch what you are
doing, and use common sense
when operating a power tool. Do
not use a power tool while tired or
under the influence of drugs,
alcohol, or medication. A moment of
inattention while operating power tools
may result in serious personal injury.
2. Dress properly. Do not wear loose
clothing or jewelry. Contain long
hair. Keep your hair, clothing, and
gloves away from moving parts.
Loose clothes, jewelry, or long hair
can be caught in moving parts.
3. Avoid accidental staring. Be sure
the Power Switch is off before
plugging in. Carrying power tools
with your finger on the Power Switch,
or plugging in power tools with the
Power Switch on, invites accidents.
4. Remove adjusting keys or
wrenches before turning the power
tool on. A wrench or a key that is left
attached to a rotating part of the power
tool may result in personal injury.
5. Do not overreach. Keep proper
footing and balance at all times.
Proper footing and balance enables
better control of the power tool in
unexpected situations.
6. Use safety equipment. Always wear

Page 6
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eye protection. Dust mask, non-skid
safety shoes, hard hat, or hearing
protection must be used for
appropriate conditions.
Tool Use and Care
1. Use clamps (not included) or other
practical ways to secure and
support the workpiece to a stable
platform. Holding the work piece by
hand to against your body is unstable
and may lead to loss of control.
2. Do not force the tool. Use the
correct tool for your application.
The correct tool will do the job better
and safer at the rate for which it is
designed.
3. Do not use the power tool if the
Power Switch does not turn it on or
off. Any tool that cannot be controlled
with the Power Switch is dangerous
and must be replaced.
4. Disconnect the Power Cord Plug
from the power source before
making any adjustments, changing
accessories, or storing the tool.
Such preventive safety measures
reduce the risk of starting the tool
accidentally.
5. Store idle tools out of reach of
children and other untrained
persons. Tools are dangerous in the
hands of untrained users.
6. Maintain tools with care. Keep
cutting tools maintained and clean.
Properly maintained tools are less
likely to bind and are easier to control.
Do not use a damaged tool. Tag
damaged tools “Do not use” until
repaired
7. Check for misalignment or binding
of moving parts, breakage of parts,
and any other condition that may
affect the tool’s operation. If
damaged, have the tool serviced
before using. Many accidents are
caused by poorly maintained tools.
8. Use only accessories that are
recommended by the manufacturer
for your model. Accessories that may
be suitable for one tool may become
hazardous when used on another tool.
Service
1. Tool service must be performed only
by qualified repair personnel. Service
or maintenance performed by
unqualified personnel could result in a
risk of injury.
2. When servicing a tool, use only
identical replacement parts. Use of
unauthorized parts or failure to follow
maintenance instructions may create a
risk of electric shock or injury.
SPECIFIC SAFETY RULES
1. Maintain labels and nameplates on
the tool. These carry important
information. If unreadable or missing,
contact TOOLEX INDUSTRIAL for a
replacement.
2. Always wear the approved safety
impact eye goggles and heavy work
gloves when suing the tool. Using
personal safety devices reduce the
risk for injury. Safety impact eye
goggles and heavy work gloves are
available from Harbor Freight Tools.
3. Maintain a safe working
environment. Keep the work area
well lit. Make sure there is adequate
surrounding workspace. Always keep
the work area free of obstructions,
grease, oil, trash, and other debris. Do
not use a power tool in areas near
flammable chemicals, dusts, and

Page 7
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vapors. Do not use this product in a
damp or wet location.
4. Avoid unintentional starting. Make
sure you are prepared to begin work
before turning on the tool.
5. Never leave the tool unattended
when it is plugged into an electrical
outlet. Turn off the tool, and unplug it
from its electrical outlet before leaving.
6. Always unplug the tool from its
electrical outlet before performing
and inspection, maintenance, or
cleaning procedures.
7. Prevent eye injury and burns.
Wearing and using the approved
personal safety clothing and safety
devices reduce the risk for injury.
a. Wear the approved safety impact
eye goggles with a welding helmet
featuring at least a number 10
shade lens rating.
b. Leather leggings, fire resistant
shoes or boots should be worn
when using this product. Do not
wear pants with cuffs, shirts with
open pockets, or any clothing that
can catch and hold molten metal
or sparks.
c. Keep clothing free of grease, oil,
solvents, or any flammable
substances. Wear dry, insulating
gloves and protective clothing.
d. Wear an approved head covering
to protect the head and neck. Use
aprons, cape, sleeves, shoulder
covers, and bibs designed and
approved for welding and cutting
procedures.
e. When welding/cutting overhead or
in confined spaces, wear flame
resistant ear plugs or ear muffs to
keep sparks out of ears.
8. Prevent accidental fires. Remove
any combustible material from the
work area.
a. When possible, move the work to
a location well away from
combustible; protect the
combustibles with a cover made of
fire resistant material.
b. Remove or make safe all
combustible materials for a radius
of 35 feet (10 meters) around the
work area. Use a fire resistant
material to cover or block all open
doorways, windows, cracks, and
other openings.
c. Enclose the work area with
portable fire resistant screens.
Protect combustible walls, ceilings,
floors, etc., from sparks and heat
with fire resistant covers.
d. If working on a metal wall, ceiling,
etc., prevent ignition of
combustibles on the other side by
mobbing the combustibles to a
safe location. If relocation of
combustibles is not possible,
designate someone to serve as a
fire watch, equipped with a fire
extinguisher, during the welding
process and for at least one half
hour after the welding is
completed.
e. Do not weld or cut on materials
having a combustible coating or
combustible internal structure, as
in walls or ceilings, without an
approved method for eliminating
the hazard.
f. Do not dispose of hot slag in
containers holding combustible
materials. Keep a fire extinguisher
nearby and know how to use it.
g. After welding or cutting, make a
thorough examination for evidence
of fire. Be aware that easily visible
smoke or flame may not be

Page 8
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present for some time after the fire
has started. Do not weld or cut in
atmospheres containing
h. Dangerously reactive or
flammable gases, vapors, liquids,
and dust.
i. Provide adequate ventilation in
work areas to prevent
accumulation of flammable gases,
vapors, and dust. Do not apply
heat to a container that has held
an unknown substance or a
combustible material whose
contents, when heated, can
produce flammable or explosive
vapors. Clean and purge
containers before applying heat.
Vent closed containers, including
castings, before preheating,
welding, or cutting.
9. Avoid overexposure to fumes and
gases. Always keep your head out of
the fumes. Do not breathe the fumes.
Use enough ventilation or exhaust, or
both, to keep fumes and gases from
your breathing zone and general area.
! Where ventilation is questionable,
have a qualified technician take
an air sampling to determine the
need for corrective measures.
Use mechanical ventilation to
improve air quality. If engineering
controls are not feasible, use an
approved respirator.
! Work in a confined area only if it
is well ventilated, or while
wearing an air-supplied
respirator.
! Follow OSHA guidelines for
Permissible Exposure Limits
(PEL’s) for various fumes and
gases.
! Follow the American Conference
of Governmental Industrial
Hygienists recommendations for
Threshold Limit Values (TLV’s)
for fumes and gases.
! Have a recognized specialist in
Industrial Hygiene or
Environmental Services check
the operation and air quality and
make recommendations for the
specific welding or cutting
situation.
10. Always keep hoses away from
welding/cutting spot. Examine all
hoses and cables for cuts, burns, or
worn areas before each use. If any
damaged areas are found, replace the
hoses or cables immediately.
11. Read and understand all
instructions and safety precautions
as outlined in the manufacturer’s
WARNING
INHALATION HAZARD: Welding and
Plasma Cutting Produce
TOXIC FUMES.
Exposure to welding or cutting exhaust fumes
can increase the risk of developing certain
cancers, such as cancer of the larynx and
lung cancer. Also, some diseases that may be
linked to exposure to welding or plasma
cutting exhaust fumes are:
a. Early onset of Parkinson’s Disease
b. Heart disease
c. Ulcers
d. Damage to the reproductive organs
e. Inflammation of the small intestine or
stomach
f. Kidney damage
g. Respiratory diseases such as
emphysema, bronchitis, or pneumonia
Use natural or forced air ventilation and wear
a respirator approved by NIOSH to protect
against the fumes produced to reduce the risk
of developing the above illnesses.

Page 9
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
Manual for the material you will
weld or cut.
12. Proper cylinder care. Secure
cylinders to a cart, wall, or post, to
prevent them from falling. All cylinders
should be used and stored in an
upright position. Never drop or strike a
cylinder. Do not use cylinders that
have been dented. Cylinder caps
should be used when moving or
storing cylinders. Empty cylinders
should be kept in specified areas and
clearly marked “empty.”
13. Never use oil or grease on any
inlet connector, outlet connector,
or cylinder valves.
14. Use only supplied Torch on this
Inverter Air Plasma Cutter. Using
components from other systems may
cause personal injury and damage
components within.
15. People with pacemakers should
consult their physician(s) before using
this product. Electromagnetic fields in
close proximity to a heart pacemaker
could cause interference to, or failure
of the pacemaker.
16. USE PROPER EXTENSION
CORD.
Make sure your extension cord is in
good condition. When using an
extension cord, be sure to use one
heavy enough to carry the current your
product will draw. An undersized cord
will cause a drop in line voltage
resulting in loss of power and
overheating. We recommend that a
15amp extension cord be used with
the 1.5mm2 cable. The following
Toolex Industrial Extension Leads
would be suitable 594530 10 metre,
594531 20 metre & 594532 30
metre.

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SPECIFICATIONS
Model
Item
511307 511467 511625
Rated input voltage(V) 1 Phase 240V - 50Hz 1 Phase 240V - 50Hz 1 Phase 240V - 50Hz
Rated input current）(A) 24.8 25.6 26
Rated input power (KVA) 27A 33A 38.65A
Wire speed (M/MIN) 2 - 18 2 - 18 0 - 10
Welding current（MMA 10 - 170 20 - 180 -
Welding current）-MIG 40-170 40 - 200 40 - 250
No-load voltage（V） 65V 65V 39V
Duty cycle 120A@100%:
170A@30%
140A @ 100%
170A @ 60%
160A @ 100%
200A @ 60%
Wire diameter (mm) Ф0.6 - 0.8 - 0.9 Ф0.6 - 0.8 - 0.9 - 1.2 Ф0.6 - 0.8 - 0.9 - 1.2
Welding thickness (mm) 0.6~4.0 0.6~6.0 0.8~10.0
Cover protection IP21S IP21S IP21S
Insulation F F F
Dimension
（L×W×H mm） 520 x 330 x 360 520 x 335 x 365 870 x 390 x 610
Weight（kg） 9.5 15 48

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Duty Cycle
Duty Cycle is the equipment
specifications which defines the number of
minutes within a 10 minute period that a
piece of equipment can safely operate.
Example for welding duty cycle
30%@170Amps is as follows, which
means that it continuously operates for 3
minutes at maximum output during a 10
minute period.
CAUTION: Failure to observe the duty
cycle limitations of this MIG MACHINE
can easily damage this equipment, and
will void warranty.
UNPACKING
When unpacking, checks to make sure the
following parts are included.
Inverter welding machine with
MIG torch with Power Cord
Ground cable with Clamp
If any parts are missing or broken, please
call PROCRAFT at the number on the
cover of this manual.
Preparing Your Work Area
1. You must have a sturdy work table
that is open below the area you are
welding. Molten slag will be blown
through the work metal, and must be
able to fall away freely
2. Your work table must allow the work
metal to be firmly clamped to prevent it
accidentally falling or moving.
3. The floor and surrounding area of your
work site must not be flammable. A
clean cement floor is recommended.
The cutting process will eject molten
metal slag onto the floor, and it will
scatter for 8-10 feet or more in any
direction. Have an adequate fire
extinguisher available if needed.
ASSEMBLY
Attach air supply:
Caution: Do not use an Argon/Mixed
pressure regulator/flow meter with CO2
Shielding gas. To use CO2 Shielding gas,
you must install a CO2 Shielding gas
pressure regulator/flow meter.
1. Make sure the Flow Adjust on the
Pressure Regulator/Flow Meter is
turned off. Then Pressure
Regulator/Flow Meter (not included)
firmly onto the cylinder valve.
2. Connect the gas air inlet (1) to your
supply CO2 Gas supply by one air
hose (not supplied). And remember to
fasten it with coupling.
3. Adjust the flow rate of the gas by
turning the Flow Adjust. The typical
flow rate is 10-30 CFH (cubic feet per
hour). Make sure to check the
Welding Wire manufacturer’s
recommended flow rate.
Front Panel and Instruction
Gasinlet(1) 

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1. “ ” Mode Selector :
Choosing MIG, MMA, TIG Welding
according the work needed.
” MIG welding: when you
chose this welding mode, please
plug the welding plug with cable to
the MIG control socket 10 and plug
the earth cable to socket 8. (Refer to
page 9, (1)).
“” MMA welding: when you
chose this welding mode, please
connect the MMA welding plug and
earth cable plug to socket 8 or 9.
They can be exchanged. (Refer to
page 9, (1)).
“” TIG welding: when this TIG
welding mode is selected, please
connect the TIG torch control cable
in to TIG control socket 8 and
connect the earth cable to the socket
2. “ ”” ”Working
Indicator Light. It will be on during
welding operation.
3. “”Thermal Overload Indicator
Lamp. This light will come on, and the
device will shut down if the tool
becomes overheated. Stop trying to
use the cutter while leaving the power
switch onto allow the cooling fan to
operate, and the lamp will turn off
automatically when the machine cools
down. Please pay attention to the Rated
Duty Cycle discussed on page 11.
4.
Manual wire feeding:
The welder begins to feed the wire,
when this button is pressed and the
1
2
4
3
7
5
8
7
6
6
9
9
5
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1
10

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Page 13
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wire won’t stop running until this
trigger is released.
5. “MIG/MMA/TIG” You can adjust the
welding current by turning this knob.
for all welding functions MIG /
MMA / TIG.
6. Spool Gun Connection
7. Euro Mig Torch Connector
8. "+" Output Connector
9. "-" Output Connector
For Model 511625:
10. Burn Back Adjustment, sets the
amount of wire that will be burnt
back once weld is complete.
11. Spot Weld Timer, adjusts the
length of spot weld time.
12. Soft Start, controls the voltage
supply when the weld is starting
TIG Torch Connect
MMA welding
MIG welding connect
Setting
t
he Gun polarity For Wire
t
ype
1. Set for Electrode Positive (GAS) for
gas welding with solid-core wire and
the gas supply is needed.
Note: When it is gas welding, you also
should set common Wire feed rolls
2. Set for Electrode Negative (DCEN) for
gasless flux core wire and this kind
connect don’t need gas supply.
Note: When it is gasless welding, you also
should set the special Wire feed rolls.
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With
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Page 14
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Assembly the wire feeder
Note:
When installing wire of a different size or composition, you will also need to
change wire settings, set the gun polarity, and, possibly, install a gas cylinder, Refer to the
below:
1. Important: Securely hold onto the end of the Welding Wire and keep tension on it
during the following steps. If this is not done the welding wire will spring back and
creating a tangled “bird’s nest” and resulting in wasted wire.
2. Hold the Welding Wire securely while you cut enough Wire off the end of the
Spool to remove all bent and crimped Wire. Make sure the cut end has no burrs or
sharp edges (cut again, if needed).
3. Loosen and lower the Tension Adjusting Knob (1a) on the Wire Feed Assembly.
Then, raise the Swing Arm (2a)
4. Keep tension on the Welding Wire, and guide at least 12 inches of Wire into the
Wire Feed Leader (3a).
5. Lower the Swing Arm (2a) on the Wire Feed Assembly. Lower and tighten the
Tension Adjusting Knob (1a). Once the Wire is held in place, you may release it.
6. Lay the Torch Cable out in a straight line so that the Welding Wire moves through it
easily.
Pip
e
Powe rbox
Tension Adjusting
Knob (1a)
Wire Feed
Leader (3a)
Swing
Arm (2a)

Page 15

OPERATION
Note: Before beginning, please read and understand all the safety precautions
staring on page 1 and especially the section “Specific Safety Rules” starting on
page 3.
MIG Welding
1. Turn the Current Adjustment Knob to meet the needs of the job.
2. Move the Model Selector Switch to “MIG”.
3. Put the metal to be welded on the metal weeding-cutting table. Ensure the metals to
be welded are clean, so good welding efficiency can be promised.
4. Place the MIG welding unit no closer than six feet from the work piece to be welded
5. Connect the MIG torch control, cable plug as shown on page 10. Twist to lock in
place.
6. Plug in the Grounding Cable into the Ground Connector on the upper of the unit front.
Twist to lock.
7. Securely place the clamping end of the Grounding Cable Clamp to a part of the work
piece or metal table that is clean of paint, oil, or dirt. Clamp as close as possible to the
work piece without damaging the cable during welding.
8. Assemble the desired accessories and tips inside the tip of the MIG Torch handle.
Insert the Contact Tip (2b) onto the Welding Wire and screw it firmly into the Head
Tube (3b) of the Torch Handle. Replace the Nozzle (1b), and cut off any excess
Welding Wire over 1/2 inches.
9. Connect a hose and coupling from the gas regulator on a CO2 gas tank (none
included) to the CO2 Gas Inlet on the back of the unit. Follow the gas cylinder
manufacturer’s instructions for set-up and use.
10. Verify that the Power Switch is in the off position, then plug the 240~line cord plug into
an appropriate 240~outlet.
11. When everything is in place for welding, press the Power Switch UP to the ON
position. The Power Light” will illuminate, but the Torch is not yet
energized.
12. Point the Torch Handle away from all objects. Then, press the Trigger Switch (51e) on
the Torch Handle until the Welding Wire feeds through the Head Tube (51c) of the
Torch Handle about 2 inches. If necessary, move the Torch Handle slightly in a circular
motion to help feed the Welding Wire properly out of the Head Tube.
13. Press the torch and orient yourself to one side of the area to be welded, and move the
Welding Helmet Face Shield (not included, see page 4 item 7) over your eyes.

Page 16
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14. Caution: The Torch handle is now energized. Be careful not touch anything else with
the Torch except the work piece to be welded.
15. Hold the Trigger down and tilt the torch forward. Keep the wire touch the work piece.
16. When the arc ignites, tilt the tip forward and hold it touch the work piece.
17. Never tap the Welding Wire into the welding surface to ignite the arc. This will cause
the Welding Wire to stick to the work piece.
18. For a narrow weld, you can usually draw the Welding Wire in a steady straight line.
This is called a “stringer bead”
19. For a wider weld, draw the Welding Wire back and forth across the joint in a curve.
This is called a “weave bead”.
TIG Welding
1. Turn the Current Adjustment Knob to meet the needs of the job.
2. Move the Model Selector Switch to “MIG”.
3. Put the metal to be welded on the metal weeding-cutting table. Ensure the metals to
be welded are clean, so good welding efficiency can be promised.
4. Hold the Trigger down and tilt the torch forward. Keep a constant distance between
the torch and the work piece but do not contact it.
5. Stroke the work piece lightly to ignite the arc. Do not strike like a match? Never tap the
electrode wire to ignite the arc; it will damage the electrode.
6. When the arc ignites, tilt the electrode forward and hold it near the work piece.
Arc (stick) Welding
1. Turn the Current Adjustment Knob to meet the needs of the job.
2. Move the Stick or TIG Switch to “TIG”
3. Connect the Electrode Clamp and Cable to the torch control connector (as 7 shown on
page 9 and twist to lock in place.
4. Plug the cable of the Grounding Clamp into the DC ground connector and secure the
clamp to a clean, exposed metal part of the work piece.
5. Place the metal portion of the welding rod inside the jaws of the Electrode Clamp.
Welding rod types vary for welding different metals.
Note: If too much current is drawn from the welder; the Thermal Overload protector will
activate, the Overload indicator will light, and the welder will turn off until it cools
down. It will automatically reset.
When finished welding
a) Release the Torch handle trigger and lift the Torch handle from the work
piece,
b) Press the Power Switch to the Off (O) position.
c) Set the Torch handle down on the metal workbench,
d) Turn the air supply off,
e) Unplug the line cord from the electrical outlet.

Page 17
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Excess or
Burn-through
Weld droops on top
and underneath, or falls
through entirely,
making a hole
Proper
Weld is visible underneath and
bulges slightly on top.
Inadequate
Weld does not contact the
joint fully, just on the
surface.
Possible
causes
and Solutions
1. Excessive material at weld:
Reduce wire feed speed
2. Overheating:
Increase welding speed and
ensure that welding speed is kept
steady.
Welding not adhering properly
Gaps present between weld and previous
bead or between weld and work piece.
Possible
causes
and Solutions
1. Dirty work piece:
Make certain that work piece is clean
and free from oil, coatings, and other
residues.
2. Insufficient weld material:
Increase wire feed speed.
3. Incorrect welding technique:
Place stringer bead at correct place in
joint. Adjust work piece position or weld
angle to permit proper welding at
bottom of work- piece.
Pause briefly at sides when using a
weave bead. Keep arc on leading edge
of weld puddle. Hold gun at proper
angles and make tack welds to help
hold pieces.
Possible
causes
and Solutions
1. Work pieces too thick/close:
Joint design must allow weld to
reach bottom of groove and allow
proper welding procedures.
2. Incorrect welding technique:
Maintain
1
/ 2”or less stick out. Keep
arc on leading edge of weld puddle.
Hold gun at proper angles.
3. Insufficient weld material:
Increase wire feed speed.
4. Insufficient weld heat:
Reduce Welding Speed.
Bent at joint
Possible
causes
and Solutions
1. Improper clamping:
Make sure that pieces are clamped
securely in place.
2. Excessive heat:
Weld a small portion and allow
cooling before proceeding.
Reduce wire feed speed.

Page 18

I
n
s
pect
io
n
, M
a
i
ntenance
,
an
d
clean
i
n
g
WARNING!
Before performing any maintenance on the Welder, unplug the
p
ower
cord
(54) from its electrical outlet and allow all
components of the Welder to completely cool.
1. Periodically open the Access Panel
from the machine and, using
compressed air, blow out all dust and
debris from the interior
2. Always store the welder in a clean,
dry, safe location out of reach of
children and other unauthorized
people.
3. For optimal weld quality, clean and
inspect the contact tip and nozzle
before each use, as follows:
4. inspect the Contact T
ip (51b) and Nozzle (51a) before each use, as follows:
Nozzle Inspection,
c
leaning,
1. Turn the Nozzle (1b)
counterclockwise while
pulling to remove.
2. Scrub the interior of the Nozzle
clean with a wire brush.
3. Examine the end of the
nozzle(1a).The end should be flat
and even, If the end is uneven,
chipped, melted, cracked, or
otherwise damaged, the nozzle will
adversely effect the weld and
should be replaced.
4. Reinstall the Nozzle (1a)
after inspecting and cleaning
the Contact Tip.
Contact tip Inspection,
cleaning, and replacement
1. Make sure the entire Welding torch is
completely cool before proceeding.
2. Remove the nozzle as explained
above. Then remove the contact tip.
3. Scrub the exterior of the contact tip
clean with a wire brush. Check that
the contact tip is the proper type for
the wire size used.
4. Examine the hole at the end of the
contact tip for the following problems:
Shape: The hole should be an even
circle, and should not be oblong or
have any bulges in it.
Size: The Contact Tip will decrease
in efficiency as the center hole
enlarges. A Contact Tip that
measures 150% or more the original
size* should be replaced. (*.045” or
more for .030”
t
ips; .035” or more
for .023
t
ips.)
5. If any problems are noted with a
Contact Tip (1b), it is recommended
to have it replaced.
6. When inspection and maintenance is
completed, reinstall the Contact Tip
(1b) and Nozzle (2b).

Page 19

Gas metal arc welding
Gas metal arc welding (GMAW),
sometimes referred to by its subtypes
metal inert gas (MIG) welding or metal
active gas (MAG) welding, is a
semi-automatic or automatic arc welding
process in which a continuous and
consumable wire electrode and a shielding
gas are fed through a welding gun. A
constant voltage, direct current power
source is most commonly used with
GMAW, but constant current systems, as
well as alternating current, can be used.
There are four primary methods of metal
transfer in GMAW, called globular,
short-circuiting, spray, and pulsed-spray,
each of which has distinct properties and
corresponding advantages and limitations.
Welding gun and wire feed unit
The typical GMAW welding gun has a
number of key parts—a control switch, a
contact tip, a power cable, a gas nozzle,
an electrode conduit and liner, and a gas
hose. The control switch, or trigger, when
pressed by the operator, initiates the wire
feed, electric power, and the shielding gas
flow, causing an electric arc to be struck.
The contact tip, normally made of copper
and sometimes chemically treated to
reduce spatter, is connected to the
welding power source through the power
cable and transmits the electrical energy
to the electrode while directing it to the
weld area. It must be firmly secured and
properly sized, since it must allow the
passage of the electrode while maintaining
an electrical contact. Before arriving at the
contact tip, the wire is protected and
guided by the electrode conduit and liner,
which help prevent buckling and maintain
an uninterrupted wire feed. The gas nozzle
is used to evenly direct the shielding gas
into the welding zone—if the flow is
inconsistent, it may not provide adequate
protection of the weld area. Larger nozzles
provide greater shielding gas flow, which
is useful for high current welding
operations, in which the size of the molten
weld pool is increased. The gas is
supplied to the nozzle through a gas hose,
which is connected to the tanks of
shielding gas. Sometimes, a water hose is
also built into the welding gun, cooling the
gun in high heat operations. The wire feed
unit supplies the electrode to the work,
driving it through the conduit and on to the
contact tip. Most models provide the wire
at a constant feed rate, but more
advanced machines can vary the feed rate
in response to the arc length and voltage.
Some wire feeders can reach feed rates
as high as 30.5 m/min (1200 in/min), but
feed rates for semiautomatic GMAW
typically range from 2 to 10 m/min
(75–400 in/min)

Page 20

Power supply
Most applications of gas metal arc welding
use a constant voltage power supply. As a
result, any change in arc length (which is
directly related to voltage) results in a
large change in heat input and current. A
shorter arc length will cause a much
greater heat input, which will make the
wire electrode melt more quickly and
thereby restore the original arc length.
This helps operators keep the arc length
consistent even when manually welding
with hand-held welding guns. To achieve a
similar effect, sometimes a constant
current power source is used in
combination with an arc voltage-controlled
wire feed unit. In this case, a change in arc
length makes the wire feed rate adjust in
order to maintain a relatively constant arc
length. In rare circumstances, a constant
current power source and a constant wire
feed rate unit might be coupled, especially
for the welding of metals with high thermal
conductivities, such as aluminum. This
grants the operator additional control over
the heat input into the weld, but requires
significant skill to perform successfully.
Alternating current is rarely used with
GMAW; instead, direct current is
employed and the electrode is generally
positively charged. Since the anode tends
to have a greater heat concentration, this
result in faster melting of the feed wire,
which increases weld penetration and
welding speed? The polarity can be
reversed only when special
emissive-coated electrode wires are used,
but since these are not popular, a
negatively charged electrode is rarely
employed
Technique
The basic technique for GMAW is quite
simple, since the electrode is fed
automatically through the torch. By
contrast, in gas tungsten arc welding, the
welder must handle a welding torch in one
hand and a separate filler wire in the other,
and in shielded metal arc welding, the
operator must frequently chip off slag and
change welding electrodes. GMAW
requires only that the operator guide the
welding gun with proper position and
orientation along the area being welded.
Keeping a consistent contact tip-to-work
distance (the stick out distance) is
important, because a long stick out
distance can cause the electrode to
overheat and will also waste shielding gas.
Stick out distance varies for different
GMAW weld processes and applications.
For short-circuit transfer, the sickout is
generally 1/4 inch to 1/2 inch, for spray
transfer the stick out is generally 1/2 inch.
The position of the end of the contact tip to
the gas nozzle are related to the stick out
distance and also varies with transfer type
and application. The orientation of the gun
is also important—it should be held so as
to bisect the angle between the work
pieces; that is, at 45 degrees for a fillet
weld and 90 degrees for welding a flat
surface. The travel angle, or lead angle, is
the angle of the torch with respect to the
direction of travel, and it should generally
remain approximately vertical. However,
the desirable angle changes somewhat
depending on the type of shielding gas
used—with pure inert gases; the bottom of
the torch is often slightly in front of the
upper section, while the opposite is true
when the welding atmosphere is carbon
dioxide.