Chicago Electric MIG-100 91124 User manual

®
MIG-100 WELDERMIG-100 WELDER
MIG-100 WELDERMIG-100 WELDER
MIG-100 WELDER
WITH THERMAL OVERLOADWITH THERMAL OVERLOAD
WITH THERMAL OVERLOADWITH THERMAL OVERLOAD
WITH THERMAL OVERLOAD
ASSEMBLY AND OPERATING INSTRUCTIONS
3491 Mission Oaks Blvd., Camarillo, CA 93011
Visit our Web site at http://www.harborfreight.com
Copyright©2004 by Harbor FreightTools®. Allrights reserved.Noportionof this
manual or any artwork contained herein may be reproduced in any shape or
form without the express written consent of Harbor Freight Tools.
For technical questions and replacement parts, please call 1-800-444-3353.
91124
REVISED 12/04

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Specifications
SaveThis Manual
You will need the manual for the safety warnings and precautions, assembly instructions,
operating and maintenance procedures, parts list and diagram. Keep your invoice with this
manual. Write the invoice number on the inside of the front cover. Keep the manual and
invoice in a safe and dry place for future reference.
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!
1. Keep work area clean. Cluttered areas invite injuries.
2. Observe work area conditions. Do not use machines or power tools in damp or wet
locations. Don’t expose to rain. Keep work area well lighted. Do not use electrically
powered tools in the presence of flammable gases or liquids.
3. Keep children away. Children must never be allowed in the work area. Do not let them
handle machines, tools, or extension cords.
4. Store idle equipment. When not in use, tools must be stored in a dry location to inhibit
rust. Always lock up tools and keep out of reach of children.
5. Do not force tool. It will do the job better and more safely at the rate for which it was
intended. Donotuseinappropriate attachments in an attempt toexceedthetoolcapacity.
ITEM DESCRIPTION
Welding Current 90 AMPs
Duty Cycle 10%@90AMPs
Power Consumption 110VAC, 23 amps
Heat Control Switch on Unit This model is not adjustable
Ground Cable 4 AWG, single insulation, 6 foot
Torch Power Cable 8 AWG, single insulation, 6 foot
Power Cord 3-core, double insulated, 14 AWG, U.L. approved
Power Cord Plug UL Approved
Thermal Overload Both settings: 10 min. shutdown, 3 min. back on with Light
WelderTip 0.030”;Spare:WelderTip 0.035 inch;
Will also accept 0.023” welder tip
Wire Size 0.030 inch flux core wire when using 0.030”WelderTip
Wire Spool Size 4 inches diameter
Overall Dimensions 14-1/2 (L) x 8-1/2 (W) x 15-1/2 (H) inches
Weight 34.45 lbs.
Accessories SpareWelderTip
Welding Face Shield
Wire Brush / Hammer combination
REV 06/04

Page 3SKU 91124
6. Use the right tool for the job. Do not attempt to force a small tool or attachment to do
the work of a larger industrial tool.There are certain applications for which this tool was
designed. Do not modify this tool and do not use this tool for a purpose for which it was
not intended.
7. Dress properly. Do not wear loose clothing or jewelry as they can be caught in moving
parts. Protective, electrically nonconductive clothes and nonskid footwear are
recommended when working. Wear restrictive hair covering to contain long hair.
8. Use eye and ear protection. Always wear ANSI approved, arc shaded, impact safety
face shield. Always use the full face shield (provided) when arc welding.Wear an ANSI
approved dust mask or respirator when working around metal, chemical dusts, fumes
and mists.
9. Do not overreach. Keep proper footing and balance at all times. Do not reach over or
across running machines.
10. Maintain tools with care. Keep tools sharp and clean for better and safer performance.
Followinstructionsforlubricatingandchangingaccessories.Inspecttoolcordsperiodically
and, if damaged, have them repaired by an authorized technician.The handles must be
kept clean, dry, and free from oil and grease at all times.
11. Disconnect power.Unplug tool when not in use.
12. Remove adjusting keys and wrenches. Check that keys and adjusting wrenches are
removed from the tool or machine work surface before plugging it in.
13. Avoid unintentional starting. Be sure the switch is in the Off position when not in use
and before plugging in.Do not carry any tool with your finger on the trigger, whether it is
plugged in or not.
14. Stay alert. Watch what you are doing, use common sense. Do not operate any tool
when you are tired.
15. Check for damaged parts. Before using any tool, any part that appears damaged
should be carefully checked to determine that it will operate properly and perform its
intended function.Check for alignment and binding of moving parts;any broken parts or
mounting fixtures; and any other condition that may affect proper operation. Any part
that is damaged should be properly repaired or replaced by a qualified technician. Do
not use the tool if any switch does not turn On and Off properly.
16. Guard against electric shock. Prevent body contact with grounded surfaces such as
pipes, radiators, ranges, and refrigerator enclosures.
17. Replacement parts and accessories. When servicing, use only identical replacement
parts. Use of any other parts will void the warranty. Only use accessories intended for
use with this tool. Approved accessories are available from Harbor Freight Tools.
18. Do not operate tool if under the influence of alcohol or drugs. Read warning labels
on prescriptions to determine if your judgment or reflexes are impaired while taking
drugs. If there is any doubt, do not operate the tool.
19. Maintenance. For your safety, service and maintenance should be performed regularly
by a qualified technician.

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20. Use proper size and type extension cord.If an extension cord is required, it must be of
the proper size and type to supply the correct current to the tool without heating up.
Otherwise, the extension cord could melt and catch fire, or cause electrical damage to
the tool.This tool requires use of an extension cord of 20 amps minimum capability (up
to 30 feet), with wire size rated at 12 AWG. Longer extension cords require larger size
wire. If you are using the tool outdoors, use an extension cord rated for outdoor use
(signified by “WA” on the jacket).
Note: Performance of this tool may vary depending on variations in local line voltage.Exten-
sion cord usage may also affect tool performance.
Warning:The warnings,cautions,and instructions discussed in this instruction manual
cannot cover all possible conditions and situations that may occur. It must be under-
stood by the operator that common sense and caution are factors which cannot be
built into this product, but must be supplied by the operator.
Arc Welding Safety Warnings and Precautions
Warning:This product,when used for welding and similar applications,produces chemi-
cals known to the State of California to cause cancer and birth defects (or other repro-
ductive harm). California Health & Safety Code 25249.5, et seq.
1. Avoid electrical shock. Do not permit electrically live parts, cables, or electrodes to
contact skin, clothing, or gloves. Protective clothing should be hole-free, dry, and ANSI
approved.
Thisunitdrawsenoughcurrenttocause serious injury or death.Beforeturning the welder
on, check the electrode holder to be sure that there are no protruding screw heads, and
that all insulation is secure. Do not weld unless you are insulated from ground and the
work piece.
2. Avoid breathing fumes or gases. They can cause serious health problems. Use an
active ventilation system directly above the welding area. Keep your head out of the
fumes.
REV 05/04

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Assembly
1. Attach the Handle (30) to the Cover (31) using screw (29) inserted from the Handle
top-rear. Refer to the photo at the top of page 6, and the Assembly Drawing on page
10.
2. Attach the Cover Locking Spring (8) to the front of the Base Frame (14) using the
supplied self-tapping screw.
Unpacking
When unpacking, check to make sure the following parts are included.
If any parts are missing or broken, please call Harbor Freight Tools at the number on the
cover of this manual as soon as possible.
Wire Spool and Spare
Welding Tip not shown here.
Torch (1)
Face Shield (38) MIG-100 Welder
Power Cord (32)
Wire Brush / Hammer (39)
Ground Cable (33)
3. Avoid eye and body damage. Arc rays and infrared radiation can injure eyes and burn
skin. Wear ANSI approved eye and body protection. Do not allow viewing by visitors
without proper eye and body protection. Use the provided Face Shield with arc shaded
filter plate.
4. Know proper arc welding practices. Read and understand the manufacturer’s
instructions, as well as your employer’s safety practices for arc welding.
5. Connect only to a code approved power source. Connect only to a grounding power
source conforming to the National Electrical Code and Local Codes.
6. Avoid fire and explosion. Remove flammable and explosive material from at least 35
feet from the welding arc to prevent welding sparks or molten metal from starting a fire.
Keep a type ABC fire extinguisher within easy reach.Thoroughly clean the object being
welded of any paint, grease, or other foreign material.
7. Avoid being burned. Always wear ANSI approved welding gear:leather gloves, leather
apron, and shoes.

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Note: What does the term“duty cycle mean?
Duty cycle is a welding equipment specification, which defines the number of minutes, within
a 10-minute period, during which a given welder can safely produce a particular welding
current. For example, this 90 amp welder with a 10% duty cycle must be rested for at least 9
minutes after 1 minute of continuous welding.
Failureto carefully observedutycycle limitations can easilyoverstress a welder’s power
generation system contributing to premature welder failure. Many welders do not have
internal protection systems that prevent this sort of over stress -- leaving the task to the
owner or operator.
Operation
The MIG 100 Welder is used to weld sheet metal and light carbon steel.
Cover Locking Spring (8)
Cover(31)
Handle(30)
Wire Reel (27)
Switch (7) Power On / Off
Switch (7) Current Min. / Max.*
Overload Indicator Light (22)
Wire Feed Speed Knob (9)
Torch (1) Cable
Ground Cable (33) Power Cord (32)
* NOTE:THIS UNIT IS
NOT ADJUSTABLE.

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Caution: Before arc welding, read and understand all safety precautions and warnings
listed on pages 2 through 5.
1. Securely clamp the Ground Cable Clamp (33) as close as possible to the metal object
to be welded, or to the metal work bench where the object is mounted and electrically
connected.
2. This unit is not adjustable. Current switch is set at 90 AMPs.
3. Verify that the Power Switch is in the OFF position, then plug the MIG-100 Welder plug
into a dedicated, 110 VAC, 20 amp line with delayed action type circuit breaker or
fuses.
If an extension cord is used, it must have the following wire size: up to 30 feet, use 12
AWG size wire; 30 to 50 feet, use 10 AWG wire; Over 50 feet, use 8 AWG wire.
4. While holding the Torch Cable Clamp with electrode wire clearly out of the way of any
grounded objects, turn the Power Switch to the ON position.
5. Momentarily press the Torch switch to test the wire feed speed.
Adjust the speed by turning the Wire Feed Speed Knob
(9).
6. Orient yourself on the area to be welded, then place the
Face Shield over your eyes.
Warning:Never look attheignited arcwithout ANSI approved,
arc shaded, eye protection in a full face shield. Permanent
eye damage or blindness can occur. Skin burns can occur.
Never breath arc fumes.
7. Press (and hold) theTorch button and stroke the area to be
welded with the electrode wire to ignite the arc.
Never tap the electrode wire into the welding surface to ignite the arc.This damages its
external coating on the electrode which prevents oxygen in the air from coming into
contact with the molten metal, causing it to oxidize.
8. Once the arc is ignited, tilt the electrode wire forward at an angle of approximately 35°.
The wire feeds automatically at a speed dependent on the Min. or Max. current setting.
Note: If too much current is drawn from the MIGWelder, theThermal Overload protector will
activate, the amber indicator will light, and the Arc Welder will turn off until it cools down.If this
happens, turn the Power Switch to the OFF position and wait about 3 ~ 5 minutes.
9. When the weld is complete, lift the electrode wire clearly away from any grounded
object, set the Face Shield down and turn toward the MIG-100 Welder and turn the
Power Switch to the OFF position.
10. Unplug the Power Cord from the electrical outlet.

Page 8SKU 91124
Maintenance
Caution:Before performing any maintenance on the MIGWelder,unplug the Power Cord
from the electrical outlet.
1. Periodically remove the Right and Left side panels (12 and 13), and using compressed
air, blow out all dust from the interior.
2. Store in a clean and dry location.
Replacing theWire Reel
When the wire on the Feed Reel is used up, you will need to replace it as follows.
1. Press on the Cover Locking Spring (8), then lift the Cover (31) using Handle (30) to
expose the Wire Feed Unit (23).
2. Unscrew the Wing Nut (25) and remove the Reel Locking Knob (26).
3. Remove the empty Wire Reel (27).
4. Place the newWire Reel over the shaft and onto the Reel Spring (24).
The wire on the reel should unwind counterclockwise
(see photo above).
5. Replace the Reel Locking Knob and the Wing Nut.
Tighten well.
6. Lift the Wire Feed Adjusting Spring (36) to remove
tension.
7. Guide at least 12 inches of wire into theTorch Sheath.
If the end of the wire is crimped or bent, cut it off.
8. Replace tension to the Wire Feed Adjusting Spring (36).
WireSheath
WireFeed Adjusting Spring(36) TensionAdjusting
Screw(37)

Page 9SKU 91124
9. Turn the Torch Handle Nozzle counterclockwise and pull to remove.
10. Turn the Contact Tip counterclockwise and remove.
11. Lay theTorch Sheath out in a straight line so that the wire moves through it easily.
Warning:The following steps require applying power to the welder. Do not touch any-
thing with theTorch Handle or an arc may be ignited.
12. Plug the Power Cord into its electrical outlet, press the Current Switch to Max., and turn
the welder ON.
13. Lift the Torch Handle and continue pressing the Trigger until the wire feeds through two
inches.
If the wire does not feed, view the Wire Feed Unit and see if the wire is being pushed.
If it is not, turn the welder OFF and add more tension to the Wire Feed Adjusting
Spring (36).
14. Turn the welder ON again and press the Trigger.
15. Once the wire is exposed, turn the welder OFF and unplug it.
16. Slide the Contact Tip over the wire and screw it into Torch Handle.
17. Replace the Nozzle and cut off any excess wire over two inches.
18. Secure the Cover.
PLEASE READTHE FOLLOWING CAREFULLY
THEMANUFACTURERAND/OR DISTRIBUTORHAS PROVIDEDTHEPARTSDIAGRAMINTHIS
MANUALASA REFERENCETOOLONLY. NEITHERTHEMANUFACTURERNORDISTRIBUTOR
MAKES ANY REPRESENTATION OR WARRANTY OF ANY KINDTOTHE BUYERTHAT HE OR
SHE IS QUALIFIED TO MAKE ANY REPAIRS TO THE PRODUCT OR THAT HE OR SHE IS
QUALIFIED TO REPLACE ANY PARTS OF THE PRODUCT. IN FACT, THE MANUFACTURER
AND/ORDISTRIBUTOREXPRESSLY STATESTHATALLREPAIRSANDPARTSREPLACEMENTS
SHOULD BE UNDERTAKEN BY CERTIFIED AND LICENSEDTECHNICIANS AND NOT BYTHE
BUYER. THE BUYER ASSUMES ALL RISK AND LIABILITY ARISING OUT OF HIS OR HER
REPAIRS TO THE ORIGINAL PRODUCT OR REPLACEMENT PARTS THERETO, OR ARISING
OUTOF HIS OR HER INSTALLATIONOF REPLACEMENTPARTSTHERETO.

Page 10SKU 91124
Welder Parts List
Item # Description Qty
1Torch 1
2 Contact Tip 1
3Nozzle 1
4Liner 1
5 Fixing Pole (A) for Gun Body 1
6 Fixing Pole (B) for Gun Body 1
7Switch 2
8 Cover Locking Spring 1
9Knob 1
10 Nut 1
11 Speed Control Circuit Board 1
12 Right Side Panel 1
13 Left Side Panel 1
14 Base Frame 1
15 Foot 4
16 Washer 4
17 Self-tapping Screw, ST4.2*13 4
18 Transformer Carriage 2
19 Thermostat 1
20 Transformer 1
Item # Description Qty
21 Middle Partition Board 1
22 Overload Indicator Lamp 1
23 Wire Feed Unit 1
24 Reel Spring 1
25 Wing Nut, M6 1
26 Reel Locking Knob 1
27 Wire Reel 1
28 Reel Holder 1
29 Self-tapping Screw, ST4.2*25 1
30 Handle 1
31 Cover 1
32 Power Cord 1
33 Ground Cable 1
34 Wire Feed Roller 1
35 Wire Feed Bearing 1
36 Wire Feed Adjusting Spring 1
37 Adjustment Screw 1
38 Face Shield 1
39 Wire Brush / Hammer 1

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Welder Assembly Drawing
NOTE: Some parts are listed and shown for
illustration purposes only and are not avail-
able individually as replacement parts.

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35
34
36 35
23
19
28 24
20
23
11
Welder Assembly Photographs

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Wiring Schematic