WorksheetsIntroduction and Setting up your MIG welder
Total questions: 34
Worksheet time: 17mins
Which statement best defines MIG welding in simple terms?
Resistance process using clamped electrodes
Laser process with pulsed light energy
Gas-only process melting base metal slowly
Arc process feeding solid wire continuously
What is the technical name for MIG welding used in industry?
Flux-cored arc welding (FCAW)
Gas tungsten arc welding (GTAW)
Shielded metal arc welding (SMAW)
Gas metal arc welding (GMAW)
What is the main role of shielding gas in MIG welding?
Protect weld pool from contamination
Cool the torch between passes
Provide filler metal to the joint
Increase wire speed by pressure
Which PPE combination is most appropriate for MIG welding? (Check all that apply)
Bandana or skull cap for spatter protection
Flame-resistant jacket and leather gloves
Leather boots and jeans
Welding helmet and safety glasses
Before welding, what should you do to prepare your metal?
Leave rust to improve penetration
Dip in water to cool and harden
Heat to red to remove paint fast
Grind or brush to clean to bare metal
Why bevel the joint when welding thicker metal?
Lower amperage requirements generally
Ensure full penetration to base metal
Prevent warping during cooling
Reduce spatter from contact tip
Which polarity setting is required for MIG welding?
Variable polarity switching
DC electrode negative (straight)
DC electrode positive (reverse)
AC with balanced waveform
What gas flow rate is typically set for MIG welding mild steel?
45 to 50 cubic feet per hour
30 to 35 cubic feet per hour
5 to 10 cubic feet per hour
20 to 25 cubic feet per hour
Which step helps prevent wire feeding problems from the drive rolls?
Open side door to vent humidity
Increase voltage above rated level
Switch to AC polarity whenever possible
Adjust tension according to manual
What should you inspect in consumables before welding?
Contact tips, liners, wire condition
Work clamp paint color only
Gas cylinder label font size
Torch handle serial number
Match each setup step with its purpose.
Check your cables
Prevent loose or damaged connections
Set gas flow
Provide adequate shielding of weld
Inspect consumables
Remove worn tips and liners
Bevel the joint
Allow weld to fully penetrate
When checking for gas leaks, what practical method can you use?
Tap the regulator gently with pliers
Apply soapy water and look for bubbles
Smell near the valve for odor
Shake the cylinder to hear hissing
Which wire type is best for all‑purpose MIG welding on clean mild steel?
ER70S‑3 classification wire
ER70S‑6 classification wire
Flux‑cored E71T‑1 wire
Stainless ER308L wire
When welding dirty or rusty mild steel, which solid wire is preferred due to extra deoxidizers?
ER80S‑2 solid wire
ER70S‑6 solid wire
ER70S‑2 solid wire
ER70S‑3 solid wire
Choose the best use of .030‑inch wire diameter for mild steel.
Very thick plate at high heat
Only stainless steel joints
General all‑around applications
Thin sheet with minimal heat
For thicker material when your welder can support it, which wire diameter is suitable?
.023‑inch diameter
.035‑inch diameter
.030‑inch diameter
.028‑inch diameter
Which shielding gas mixture is commonly called C‑25 and is the best all‑purpose choice for carbon steel?
75% Argon / 25% CO2
50% Argon / 50% CO2
100% CO2 gas
90% Argon / 10% CO2
What is a typical trade‑off when using 100% CO2 shielding gas compared to C‑25?
Same bead appearance, less heat
Shallower penetration, more spatter
Deeper penetration, rougher bead
Less spatter, smoother bead
Identify the recommended stick‑out length of unmelted electrode from the contact tip during MIG welding.
1/4 inch stick‑out
3/8 inch stick‑out
1/2 inch stick‑out
3/4 inch stick‑out
Match each gun technique to its typical effect on the weld bead.
Pull (drag/trailing) technique
Narrower bead, more buildup
Push (forehand) technique
Wider bead, lower penetration
Excessive stick‑out length
Irregular arc, possible instability
Choose all statements that describe the push technique for MIG welding. (Choose 2)
Usually produces higher penetration and narrow bead
Often gives better direct view into the joint
Gun is pushed away from the puddle
Gun is pointed back and dragged
Which issue can result when the travel angle exceeds 25 degrees?
More spatter and less penetration
No change in arc stability
Improved penetration on thick plate
Reduced spatter and cleaner bead
Work angle in MIG welding is best described as which relation?
Speed of wire feed per minute
Distance from torch to base metal
Angle relative to travel direction
Gun position relative to joint
In a flat position butt weld on mild steel, what gun work angle should you hold relative to the workpiece?
About a 120-degree work angle
About a 15-degree work angle
About a 45-degree work angle
About a 90-degree work angle
For a T-joint fillet weld in the flat position, which work angle is recommended when making multiple weld passes?
Keep gun at about 60 degrees
Keep gun at about 45 degrees
Keep gun at about 75 degrees
Keep gun at about 30 degrees
On a lap joint fillet weld, what is the typical gun angle range relative to the workpiece?
Between 60 and 70 degrees
Between 10 and 20 degrees
Between 85 and 95 degrees
Between 30 and 40 degrees
In horizontal welding, why is the gun work angle dropped slightly from flat position settings?
To cool the weld puddle more quickly
To increase arc length for deep penetration
To counter gravity sag on the bottom toe
To prevent spatter forming on the top toe
Which technique helps prevent undercut at the top toe of a horizontal weld when fit-up is poor?
A long dwell at the bottom toe
A wide circular weaving path
A rapid whip-and-pause motion
A slight hesitation at the top toe
When welding vertical down on thin metal, where should you begin and how should you position the wire?
Begin at the top and keep wire away from puddle
Begin at the bottom and push wire into puddle
Begin mid-joint and drag wire through puddle
Begin at the top and circle wire around puddle
Which statement best compares vertical up and vertical down techniques? (Choose 3)
Vertical up gives better penetration on thick material
Vertical down requires starting at the top of joint
Vertical up requires starting at the bottom of joint
Vertical down is faster with less penetration
Vertical up always uses higher voltage than flat
In overhead welding, what combination helps keep the weld puddle small and controllable?
Fast travel speed with wider weave
Slow travel speed with higher voltage
Fast travel speed with lower voltage
Slow travel speed with perpendicular gun
Which travel speed principle is used by experienced MIG welders to judge correctness during a pass?
Match puddle to wire diameter precisely
Maintain constant puddle size regardless of joint
Make puddle as wide as base metal thickness
Keep puddle size no larger than thinnest section
Match each welding position or joint type to its key angle or technique.
Flat butt weld
90° work angle
Flat T-joint fillet
Gun at ~45° work angle
Lap joint fillet
Gun between 60–70°
Vertical down on thin metal
Start at top, wire away from puddle
Which action helps control weld bead size and avoid undercut in horizontal position? (Choose 3)
Use slight weave when fit-up is poor
Drop work angle by 0–15 degrees
Increase travel angle beyond 25 degrees
Maintain proper toe control with pause
Switch to drag only, never push