Tweco 251 Thermal Arc Fabricator - Manual (Page 28)

FABRICATOR 251
INSTALLATION 3-6 Manual No. 0-4847
Adjusting Regulator
Adjust control knob of regulator to the required flow rate, indicated on gauge dial. (Refer to Figure 3-3)
The gas flow rate should be adequate to cover the weld zone to stop weld porosity. Excessive gas flow rates may cause
turbulence and weld porosity.
Argon or argon based gas flow rates:
- Workshop welding: 20-30 CFH
- Outdoors welding: 30-40 CFH
Helium based or CO2 gas flow rates:
- Workshop welding: 30-40 CFH
- Outdoors welding: 40-50 CFH
NOTE
All valves downstream of the regulator must be opened to obtain a true flow rate reading
on the outlet gauge. (Welding power source must be triggered) Close the valves after the
pressure has been set.
Art # A-07280
Figure 3-3: Adjusting Flow Rate
Refer to section 4.09 for suggested gas / filler metal combinations.
NOTE
The regulator/flow meters used with argon based and carbon dioxide shielding gases are
different. The regulator/flow meter supplied is for argon based shielding gases. If carbon
dioxide is to be used a suitable carbon dioxide regulator/flow meter will need to be fitted.