Tweco 190 MIG Thermal Arc Fabricator - Manual (Page 44)

FABRICATOR 190 WELDING MACHINE
OPERATION 4-8 Manual No. 0-4838
Distance from the MIG Gun Nozzle to the Work Piece
The electrode stick out from the MIG gun nozzle should be between 5/64”(2.0mm) to 13/64”(5.0mm). This distance
may vary depending on the type of joint that is being welded.
Contact
Ti
p
Gas
Nozzle
Solid Wire Flux Cored Wire
.023”
(.6mm)
1/4” (6.4mm) 5/16” (7.9mm) 3/8” (9.5mm)
9/16”
(14.3mm)
11/16”
(17.5mm)
.030”
(.8mm)
.035”
(.9mm)
.035”
(.9mm)
.045”
(1.1mm)
Art # A-07186
Wire Diameter
Distance: ±1/16”
Figure 4-9: Optimum Contact Tip to Work Distances
Electrode Wire Size Selection
The choice of electrode wire size in conjunction with shielding gas used depends on:
- Thickness of the metal to be welded,
- Type of joint,
- Capacity of the wire feed unit and power supply,
- The amount of penetration required,
- The deposition rate required,
- The bead profile desired,
- The position of welding and
- Cost of the electrode wire.
Advantages of MIG welding forehand:
• Allows superior visibility of the weld zone
• Flatter weld bead
• Shallower penetration
Forehand Vertical Backhand
Art # A-07185
Figure 4-7: Advantages of forehand welding