MIGHTYMIG NO-GAS MIG WELDER, 100A
MODEL NO: MIGHTYMIG100.V4
Thank you for purchasing a Sealey product. Manufactured to a high standard, this product will, if used according to these instructions,
and properly maintained, give you years of trouble free performance.
IMPORTANT: PLEASE READ THESE INSTRUCTIONS CAREFULLY. NOTE THE SAFE OPERATIONAL REQUIREMENTS, WARNINGS & CAUTIONS. USE
THE PRODUCT CORRECTLY AND WITH CARE FOR THE PURPOSE FOR WHICH IT IS INTENDED. FAILURE TO DO SO MAY CAUSE DAMAGE AND/OR
PERSONAL INJURY AND WILL INVALIDATE THE WARRANTY. KEEP THESE INSTRUCTIONS SAFE FOR FUTURE USE.
1. SAFETY
1.1. ELECTRICAL SAFETY
WARNING! It is the user’s responsibility to check the following:
9 Check all electrical equipment and appliances to ensure that they are safe before using. Inspect power supply leads, plugs and all
electrical connections for wear and damage. Sealey recommend that an RCD (Residual Current Device) is used with all electrical
products.
Electrical safety information. It is important that the following information is read and understood:
9 Ensure that the insulation on all cables and on the appliance is safe before connecting it to the power supply.
9 Regularly inspect power supply cables and plugs for wear or damage and check all connections to ensure that they are secure.
Important: Ensure that the voltage rating on the appliance suits the power supply to be used and that the plug is tted with the
correct fuse.
8 DO NOT pull or carry the appliance by the power cable.
8 DO NOT pull the plug from the socket by the cable.
8 DO NOT use worn or damaged cables, plugs or connectors. Ensure that any faulty item is repaired or is replaced immediately by a
qualied electrician.
If the cable or plug is damaged during use, switch o the electricity supply and remove from use.
Ensure that repairs are carried out by a qualied electrician.
When a cable extension reel is used it should be fully unwound before connection. A cable reel with an RCD fitted is recommended
since any product which is plugged into the cable reel will be protected. The cross-section of the cable on the cable reel must be suitable
for the unit and never lower than the cross-section of the mains cable supplied with the unit.
1.2. GENERAL SAFETY
▲ DANGER! Unplug the welder from the mains power supply before performing maintenance or service.
8 Welding power sources are not suitable for use in rain or snow.
WARNING! DO NOT place the welding power source on a tilted plane as this may lead to the unit toppling over.
8 The output is rated at an ambient temperature of 20°C and the welding time may be reduced at higher temperatures.
8 Risk of electric shock: Electric shock from welding electrode can kill. DO NOT weld in the rain or snow. Wear dry insulating gloves.
8 DO NOT touch electrode with bare hands. DO NOT wear wet or damaged gloves. Protect yourself from electric shock by insulating
yourself from workpiece. DO NOT open the equipment enclosure.
8 Risk induced by welding fumes: Breathing welding fumes can be hazardous to your health. Keep your head out of the fumes. Use
equipment in an open area. Use ventilating fan to remove fumes.
8 Risk induced by welding sparks: Welding sparks can cause explosion or fire. Keep flammables away from welding. DO NOT weld near
flammables. Welding sparks can cause fires. Have a fire extinguisher nearby and have a watchperson ready to use it. DO NOT weld on
drums or any closed containers.
▲ WARNING: Risk induced by the arc: Arc rays can burn eyes and injure skin. Wear hat and safety glasses. Use ear protection and button
shirt collar. Use welding helmet with correct shade of filter. Wear complete body protection.
Risk induced by electromagnetic fields: Welding current produces electromagnetic field. DO NOT use with medical implants. Never coil
welding cables around your body. Route the welding cables together.
▲ DANGER! Never coil welding cables around your body.
9 Keep the welder and cables in good working order and condition. Take immediate action to repair or replace damaged parts and
route the welding cables together.
9 Use genuine parts and accessories only. Unapproved parts may be dangerous and will invalidate the warranty.
9 Use an air hose to regularly blow out any dirt from the liner and keep the welder clean for best and safest performance.
9 Check and spray the gas cup and contact tip regularly with anti-spatter spray, available from your Sealey stockist.
Refer to
instruction
manual
Wear a
welding
mask
Wear protective
gloves
Warning!
Electricity
Shock hazard
Warning!
Keep away
from rain
Caution
required
Arc rays can
burn eyes and
injure skin
Breathing
welding fumes
can be
hazardous to
your health
Electric shock
from welding
electrodes can
kill
Electromagnetic fields
can cause pacemaker
malfunction
Welding sparks
can cause
explosions or fire
Original Language Version
© Jack Sealey Limited
MIGHTYMIG100.V4 Issue 2 (1,6,F) 02/11/23
9 Locate welder in a suitable work area. Ensure that the area has adequate ventilation as welding fumes are harmful.
9 Keep work area clean, tidy and free from unrelated materials. Also ensure the working area has adequate lighting and that a fire
extinguisher is at hand.
WARNING! Use welding head shield to protect eyes and avoid exposing skin to ultraviolet rays given off by electric arc. Wear
safety welding gauntlets and complete body and ear protection.
WARNING! Risk induced by electromagnetic fields: Welding current produces electromagnetic field’.
WARNING! Risk induced by welding sparks: Welding sparks can cause explosion or fire. Keep flammables away from welding.
DO NOT weld near flammables. Welding sparks can cause fires. Have a fire extinguisher nearby and have a watch person ready
to use it. DO NOT weld on drums or any closed containers.
WARNING! ‘Risk induced Welding fumes: Breathing welding fumes can be hazardous to your health. Keep your head out of the
fumes. Use equipment in an open area. Use ventilating fan to remove fumes.
WARNING! Risk of electric shock: Electric shock from welding electrodes can kill. DO NOT weld in the rain or snow.
9 Remove ill fitting clothing, remove ties, watches, rings and other loose jewellery and contain long hair.
9 Ensure the workpiece is correctly secured before welding.
9 Avoid unintentional contact with the workpiece. Accidental or uncontrolled use of the torch may be dangerous and will wear the nozzle.
9 Keep unauthorised persons away from the work area. Any persons working within the area must wear a protective head shield and gloves.
9 Operators must receive adequate training before using the welder.
9 Stand correctly keeping a good footing and balance, ensure the floor is not slippery and wear non-slip shoes.
9 The output is rated at an ambient temperature of 20°C and the welding time may be reduced at higher temperatures.
8 DO NOT operate the welder if it or the cables are damaged and DO NOT attempt to t any unapproved torches or other components to
the welder.
8 DO NOT get welder wet or use in damp or wet locations or areas where there is condensation. DO NOT use welder on uneven ground.
▲ DANGER! DO NOT weld near flammable solids, liquids or gases and DO NOT weld containers or pipes which have held flammable
materials. Avoid welding materials which have been cleaned with chlorinated solvents. DO NOT use power source for pipe thawing.
8 DO NOT stand welder on a metal workbench, car bodywork or similar.
8 DO NOT touch any live metal parts of the torch or electrode while the machine is switched on.
8 DO NOT pull the welder by the cable, or the torch. Protect cables from sharp or abrasive items. DO NOT bend, strain or stand on cables
or leads.
8 DO NOT wear wet or damaged gloves.
8 DO NOT open the equipment enclosure while welder is switched on.
9 Protect from heat. Long lengths of slack must be gathered and neatly coiled. DO NOT place cables where they endanger others.
8 DO NOT touch the torch or workpiece immediately after welding as they will be very hot. Allow to cool.
8 DO NOT operate welder while under the influence of drugs, alcohol or intoxicating medication, or if tired. When not in use store the welder
in a safe, dry, childproof area.
2. INTRODUCTION
Heavy-duty high output transformer and forced-air cooling to maximize duty cycle performance. Supplied with comfort grip non-live torch,
1.8m earth cable, 0.45kg flux cored wire and 1mm contact tip. Suitable for no-gas operation only. For use with flux-cored wire.
IMPORTANT: These instructions contain the information you require to prepare your machine for welding, together with a maintenance
and a troubleshooting section. The instructions are not intended to teach you how to weld. If you have no experience, we recommend that
you seek training from an expert source. MIG welding is relatively easy, but does require a steady hand and supervised practice on scrap
metal, as it is only with continued practice that you will achieve the desired results.
3. SPECIFICATION
Model No: MIGHTYMIG100.V4
Welding Current: 55-100A
Wire Capacity: 0.9kg Gasless only
Duty Cycle: 60% @ 55A, 20% @ 90A
Cooling System: Forced Air
Fuse Rating: 13A
Gas Type: N/a
Torch: 1.8m Non-Live
Supply: 230V
Absorbed Power: 3kW
Case Size: Compact
Flux Cored Wire (0.9kg x Ø0.9mm): TG100/1
Replacement Tips 1mm (Pack of 5): TG100/2
Note: For use with 0.9kg Gasless and 0.7kg mild steel Wire Reels only.
Original Language Version
© Jack Sealey Limited
MIGHTYMIG100.V4 Issue 2 (1,6,F) 02/11/23
4. ASSEMBLY
4.1. FIT HANDLE: Slide handle onto top cover. Secure with screw (19), see Parts Diagram.
4.2. FIT COVER LOCKING SPRING: Fix Cover Locking Spring (8), see Parts Diagram, to top of front panel. Use screw, washer and spring
washer supplied. See also g.1.A.
4.3. FITTING A REEL OF WIRE
4.3.1. Depress the silver button in the front of the handle and open the top compartment. See A & B in g.1. The welder is supplied with a mini
spool containing 0.45kg of ux cored wire.
4.3.2. Referring to g.2, rotate the nut (5) anti-clockwise and remove it from the threaded spindle together with the pressure disc (4). Leave
the spring (1) on the spindle (2).
4.3.3. Place the wire reel (3) over the spindle and down onto the spring ensuring that the wire will withdraw from the spool in a forwards
direction and on the same side of the compartment as the wire feed unit.
4.3.4. Push lightly down on the top of the reel of wire and screw the pressure disc (4) onto the end of the spindle and down onto the top of the
wire reel. The reel take o pressure should be set to provide a mild braking eect to prevent overrun where loose coils of wire form on
the reel. DO NOT over tighten the pressure disc as too much braking will conict with the wire tension set on the wire drive unit.
4.3.5. Lock the position of the pressure disc by screwing the nut (5) down on top of it.
4.3.6. Referring to g.1 turn the knob on the wire lock screw (C) anti-clockwise and lift it up and away from the pressure roller moulding.
4.3.7. Swing the pressure roller moulding (D) away from the drive roller
4.3.8. Release the wire from the spool (do not allow wire to uncoil) and straighten 40-50mm of wire and gently push through the exible
plastic guide and through the 0.9mm feed roller groove (g.3.1) and into the torch liner.
4.3.9. Referring to g.4, move the pressure roller moulding back round onto the grooved drive wheel and swing down the wire lock screw to
lock it in place. See section 4.3 regarding wire tension.
4.3.10. Feeding the wire through to the torch. (See g.5) Remove gas cup (a) and contact tip (b) from end of torch as follows:
a) Take torch in left hand with the torch tip facing to the right.
b) Grasp gas cup rmly in your right hand.
c) Turn gas cup clockwise only and pull cup out to the right.
WARNING! DO NOT turn gas cup anti-clockwise, as this will damage internal spring.
d) Unscrew the copper contact tip (right hand thread) to remove.
4.3.11. Check welder is switched OFF and that the earth clamp is away from the torch tip. Connect the welder to the mains power supply and
set the voltage switch to MIN. (g.A)
4.3.12. Set the wire speed knob to position 5 or 6. Keeping the torch cable as straight as possible and press the torch switch. The wire will
feed through the torch.
4.3.13. When wire has fed through, switch welder o, unplug from mains.
a) Take torch in left hand, slide the contact tip over the wire and screw it back into place.
b) Grasp gas cup in right hand, push onto torch head and turn clockwise only.
WARNING! DO NOT turn gas cup anti-clockwise, as this will damage internal spring.
c) Cut wire so that it is just protruding from the cup.
4.4. SETTING WIRE TENSION
IMPORTANT: You must set the correct tension, too little or too much tension will cause problematic wire feed and result in a poor weld.
4.4.1. Correct tension between the rollers is checked by slowing down the wire between gloved ngers. If the pressure roller skids the
tension is correct. Try to use the lowest tension possible as too high a tension will deform the wire. When you have completed welding
allow the welder to cool before storing in a safe, dry place. Note: Damaged torches and cables are not covered under warranty.
Original Language Version
© Jack Sealey Limited
MIGHTYMIG100.V4 Issue 2 (1,6,F) 02/11/23
g.6
Original Language Version
© Jack Sealey Limited
MIGHTYMIG100.V4 Issue 2 (1,6,F) 02/11/23
5. WELDING PREPARATION
5.1. PREPARATION FOR WELDING
IMPORTANT! Before you commence, make sure the machine
is switched o at the mains. If welding a car, disconnect the battery
or t an electronic circuit protector. Ensure that you read, understand
and apply the safety instructions in section 1.
5.1.1. To ensure a complete circuit, the negative lead must be securely
attached to the workpiece close to the weld area. Best connection
is obtained by grinding the point of contact on the workpiece before
connecting the clamp.
5.1.2. The weld area must be free of paint, rust, grease, etc.
5.2. THERMAL PROTECTION, see g.6
5.2.1. Should the welder become overheated due to prolonged use beyond
the stated duty cycle the thermal protection will cause the welder to
cut out and the orange light on the front panel will illuminate. Wait
for fteen minutes for the welder to cool down at which time it will
reconnect automatically.
6. RATING PLATE
On the front panel of the welder is the ratings plate, giving the following data:
1 - The BS/EU standard relating to the safety and construction of
arc welding and associated equipment.
2 - Single phase transformer.
3 - Symbol indicates welding with a continuous ow of welding wire.
4 - Symbol for Single-phase AC supply.
5 - Rating of internal protection provided by casing.
6 - Output U0 Rated minimum and maximum no load voltage.
I2, U2 Current and corresponding voltage.
X Welding ratio based on a 10 minute cycle.
20% indicates 2 minutes welding and 8 minutes rest,
100% would indicate continuous welding.
7 - Mains Supply U1 Rated supply voltage and frequency.
I1max Maximum current.
I1e Maximum eective current.
8 - Welding current range.
9 - Serial Number. Specically identies each welder.
7. OPERATION
▲ DANGER! Unplug the welder from the mains power supply before performing maintenance or service.
7.1. WIRE FEED UNIT
7.1.1. Check the wire feed unit at regular intervals. The feed roller wire guide plays an important part in obtaining consistent results. Poor wire
feed affects the weld. Clean the rollers weekly, especially the feed roller groove, removing all dust deposits.
7.2. TORCH
7.2.1. Protect the torch cable assembly from mechanical wear. Clean the liner from the machine forwards by using compressed air. If the liner is
blocked it must be replaced.
7.3. TURNING FEED ROLLER IMPORTANT: TURN THE FEED ROLLER TO SUIT THE WIRE SIZE.
7.3.1. There are two grooves on the feed roller, 0.6mm and 0.9mm. Always have the groove that is being used on the outside of the roller
(nearest to you). To turn the feed roller first loosen the wire tension knob and move it into its up position (see fig.8-1) then move
the tensioning roller assembly to its down position (see fig.8-2). Take hold of the triangular knob on the roller retainer and rotate it
90°anticlockwise to release it as shown in fig.8.3. Now pull the roller retainer off the drive spindle to reveal the roller as shown in fig.9.
7.3.2. Pull the roller off the drive spindle, flip it over and put it back on the drive spindle. (See fig.10) The groove size you require should now be
visible on the face of the roller. Push the roller retainer back onto the drive spindle with the opening facing right. Ensure that the flanges at
the base of the retainer, seat fully into the circular recess in the main moulding and then rotate the retainer through 90° to lock it in place.
7.4. CONTACT TIP (to remove tip follow steps in 4.3.10.):
7.4.1. The contact tip is a consumable item and must be replaced when the bore becomes enlarged or oval. The contact tip MUST be kept free
from spatter.
7.5. GAS CUP (to remove cup follow steps in 4.3.10.):
7.5.1. The gas cup must also be kept clean and free from spatter. Build-up of spatter inside the gas cup can cause a short circuit at the contact
tip which will result in expensive machine repairs. To keep the contact tip free from spatter, we recommend the use of anti-spatter spray
(MIG/722308) available from your Sealey stockist.
7.6. REPLACING WIRE LINER
7.6.1. A worn or damaged wire liner will seriously affect the performance of the welder and should be immediately replaced. First wind the wire
back onto the spool and secure it. Remove the four screws securing the torch cable clamp to the wire feed unit (fig.11) and take off the
clamp.
7.6.2. Open the torch case by gripping the torch with one hand and turning the grooved ring at the base of the torch anticlockwise until it stops,
then pull it off the torch onto the torch cable. See fig.12-1.
7.6.3. Take hold of the back end of the moulding which contains the switch and pull it outwards and downwards to release it from the other
moulding as shown in fig.12.
2
3
4
5
9
1
8
6
7
7.6.4. Push the liner lock ring (2) firmly towards the brass nut and withdraw the liner from the nut.
With the torch cable as straight as possible pull the liner from the torch cable.
7.6.5. Insert the new liner into the torch cable and secure it in the wire drive unit by replacing the torch cable
clamp. See fig.11. Insert the other end of the liner through the locking ring and fully
into the brass nut in the torch head, see 2 in fig.12.
7.6.6. Check that the torch inner parts are properly seated in their respective mouldings then close the torch
by inserting the tongue on the switch moulding (fig.12-5) into the slot at the front of the other moulding.
Swing the switch moulding downwards and forwards until both parts have closed around the torch
cable. Slide the ribbed ring (fig.12-1) onto the end of the torch handle and turn it clockwise to lock.
8. TROUBLESHOOTING
PROBLEM POSSIBLE CAUSE REMEDY
Weld current interrupted Overheating protection activated due to
overload
Protection automatically resets when transformer has cooled
(approx. 15 min)
No weld current Rectifier blown Replace rectifier
No weld current Bad connection between clamp and
workpiece
Clean or grind contact surface and weld area
Break in earth lead Repair or replace earth lead
Break in torch lead Repair or replace
Feed motor not working Gear damaged or worn Replace gears
Motor defective Replace motor (Contact service agent)
Wire does not feed, feed
roller rotates
Pressure roller improperly adjusted Adjust tension
Dirt, copper, dust, etc. have collected in
torch liner
Clean the liner from the machine forward. Use compressed air.
Gas cup (nozzle) or tip defective Replace gas cup (nozzle) and/or tip. Check roller tension
(Section 3)
Deformed wire Adjust roller tension
Wire feeds unevenly Dirt, etc, in liner Clean the liner from the machine forward using compressed air
Gas cup (nozzle) or tip defective Replace gas cup (nozzle) and/or tip
Gas cup (nozzle) spattered Clean or replace gas cup (nozzle)
Feed roller groove clogged Clean feed roller
Feed roller groove deformed Replace feed roller
Pressure roller tension incorrect Adjust tension
g.11
g.8 g.9
g.10
g.12
Original Language Version
© Jack Sealey Limited
MIGHTYMIG100.V4 Issue 2 (1,6,F) 02/11/23
Unstable arc Incorrect settings Check settings
Impurities in weld area Clean and/or grind workpiece
Worn or defective gas cup (nozzle) Replace gas cup (nozzle)
Porous weld Rusty/dirty joints Clean or grind the workpiece
Torch too far from, or at wrong angle to,
workpiece
Gas cup to workpiece should be 8-10mm. Torch angle approx
75°
Wire sticking in gas cup
(nozzle)
Worn or defective gas cup (nozzle) Replace gas cup (nozzle)
Wire deformed Check roller tension
Wire speed too slow Increase wire speed
Irregular weld head Torch incorrectly held Use correct torch angle
Wire weaving in weld pool Check roller tension and adjust
Weld bead too narrow and
raised
Weld current too low Increase power and wire speed
Weld speed too fast Move torch slower and weave a little more
Weld bead too wide Weld current too high Increase power and wire speed
Weld speed too slow Move torch faster and weave less
Poor penetration Weld current too low Increase current and wire speed
Arc too long Bring torch closer to workpiece
Excessive penetration Weld current too high Decrease current and wire speed
Weld speed too slow Move torch faster
Incorrect distance of torch to workpiece Torch distance should be 8-10mm
Sealey Group, Kempson Way, Suffolk Business Park, Bury St Edmunds, Suffolk. IP32 7AR
01284 757500 sales@sealey.co.uk www.sealey.co.uk
Note: It is our policy to continually improve products and as such we reserve the right to alter data, specifications and component parts without prior
notice. Please note that other versions of this product are available. If you require documentation for alternative versions, please email or call
our technical team on technical@sealey.co.uk or 01284 757505.
Important: No Liability is accepted for incorrect use of this product.
Warranty: Lifetime guarantee on Transformer - Comprises 1 year unconditional parts and labour on all parts, followed by a lifetime guarantee (parts
and labour) conditional on registering your purchase with us online at www.sealey.co.uk.
WEEE REGULATIONS
Dispose of this product at the end of its working life in compliance with the EU Directive on Waste Electrical and Electronic Equipment
(WEEE). When the product is no longer required, it must be disposed of in an environmentally protective way. Contact your local solid
waste authority for recycling information.
Original Language Version
© Jack Sealey Limited
MIGHTYMIG100.V4 Issue 2 (1,6,F) 02/11/23
ENVIRONMENT PROTECTION
Recycle unwanted materials instead of disposing of them as waste. All tools, accessories and packaging should be sorted,
taken to a recycling centre and disposed of in a manner which is compatible with the environment. When the product
becomes completely unserviceable and requires disposal, drain any fluids (if applicable) into approved containers and
dispose of the product and fluids according to local regulations.
