Welding-T.I.G.(Tungsten Inert Gas) or G.T.A.W.(Gas Tungsten Arc   
        Welding)                                                  
Points to Remember:
                                                                  
      1. Tig welding can be used for joining practi-
         cally all metals and alloys in various thicknesses
         and types of joints.

      2. Be sure to use a cup of the correct size.
         Nozzles  having  too  small  an  orifice  tend  to
         overhead  and  either crack or deteriorate very
         rapidly.
                                                                  
      3. A water-cooled torch is recommended for
         welding currents that are above 200 or 250 amperes.
         
      4. Argon is generally the inert gas recom-
         mended for Tig welding.

      5. The power source can be either a DC or
         AC machine. With a DC machine, better penetra-
         tion is usually obtained with straight polarity. For
         some metals better welds are made with an AC
         machine having a high-frequency voltage than
         with a DC machine.                  
                                                                  
      6. The diameter of the electrode depends on
         the kind and thickness of the metal to be welded.
         Make certain the tip is properly shaped for the
         type of current used.
                                                                  
      7. When welding light gage metals, it is often
         necessary to use back-up bars.
                                                                  
      8. Before starting to weld, always check to
         make sure the electrode extends the correct
         distance.
                                                                  
      9. Follow the recommendations for the correct
         gas flow, otherwise the shielding gas will
         not be effective.
                                                                  
     10. If filler rod is to be used, be sure it is of the
         right diameter.
                                                                  
     11. Always make sure water is flowing before
         attempting to operate the shielded-gas spot
         welding gun.
                                                                  
     12. Never attempt to adjust the tungsten electrode
         without first shutting down the power
         supply machine.