Wire speed (Top Knob)

Voltage (Middle Knob)

Trigger, Over Temperature, and On/Off Switch

Wire speed (amperage) controls weld penetration

Voltage controls height and width of weld bead

Low voltage: wire stubs into work

High voltage: arc is unstable (spatters)

**BACON & EGGS FRYING!**

Uses unishield gas (argon and 25% carbon dioxide)

Select voltage and wire speed based on thickness of metal being welded

Chart inside of machines for reference

Examples

Thickness of steel Voltage Wire Speed

¼” 8 80

3/16” 5 75

1/8” 4 70

16 ga. 2.5 55

***Wire should always stick out of gun about ¼”.***

Weld bead shape depends on gun angle, direction of travel, electrode extension (stickout), travel speed, thickness of base metal, wire feed speed, and voltage

Good Weld Bead Poor Weld Bead

Fine Spatter Large spatter deposits

Uniform bead Rough, uneven bead

Good penetration into base material Slight crater during weld

Moderate crater during weld Bad overlap

Poor penetration

Excessive spatter: scattering of molten metal particles that cool to solid form near weld bead

Causes: voltage too high, wire speed too high, stickout too long

Porosity: small cavities or holes resulting from gas pockets in weld metal

Causes: stickout too long, workpiece is dirty

Excessive penetration: weld metal melting through base metal and hanging underneath weld

Causes: excessive heat input

Lack of penetration: shallow fusion between weld metal and base metal

Causes: insufficient heat input

Incomplete fusion: failure of weld metal to fuse completely with base metal or preceding bead

Causes: dirty workpiece, insufficient heat input

Burn-through: weld metal melting completely through base metal resulting in holes where no metal remains

Causes: excessive heat