How can you improve TIG Welding results?

TIG Welding Results can be improved by changing a variety of parameters depending up on the alloys being welded. The table below provides a checklist of parameters.

Tips and TricksTitanium AlloysHigh Nickel AlloysAluminum AlloysCopper AlloysStainless Steel Alloys (300 Series)
With cylinder gas supply, use a high integrity gas delivery system in place of standard rubber diaphragm regulator/flowmeter.XXXXX
Use a gas lens in the TIG torch to support a lamellar gas flow.XXXXX
Use gas flow rates in the 15-20 cfh range.XXXXX
Ascertain both raw material and filler metals are clean before welding.XXXXX
Use a high integrity TIG torch as it utilizes a high integrity gas delivery line which is not permeable to atmospheric gases. The gas line is also separate from the power cable, further enhancing gas purity.XXXXX
Use a high integrity gas supply line from the flowmeter to the gas solenoid on the welder. Conventional rubber hoses may leak.XXXXX
If a central gas supply or distribution pipeline is utilized, use a high flow moisture trap and consider use of an oxygen trap.XXXXX
Use ultra-high purity argon when possible (Grade 5.0 or better), 99.999% purity.XXXXX
With materials grater than 1/8", consider use of an argon/helium shielding gas blend for improved penetration.  XX 
Consider adding controlled amounts of hydrogen to the argon-based shielding gas (<10% H2). A CGA 350 regulator will be required when this gas is selected. The CGA 580 used with pure argon will not fit this cylinder. This mixture is not recommended for joining stainless to carbon steel. It is ideal for stainless-to-stainless joining. X  X
Use post and pre-flow when possible (1 second for each 10 amps of welding current).XXXXX
Use a trailing shielding gas if possible.XXX  
Use a high integrity regulator/flowmeter with a stainless steel diaphragm. X   
Perform inter-pass cleaning with a 300 series stainless steel brush. This will remove surface oxides for improved results. XXX 
Remove surface oxide in the weld zone using a clean stainless steel brush prior to welding.  XXX
On thicker material, set balance control to maximum penetration when possible.  X  
Match filler metal to base metal - consult AWS or CWB guidelines. For stainless to steel, use an E309 filler metal.  XXX
For dissimilar alloy joining, consider silver bearing filler metal. Service temperatures must be below the melting point of the alloy selected (typically <900° F).   X 
If the weld needs to be anodized, use a 5000 series filler metal.  X  
Use an AC square wave power supply when possible.  X  
Use a water-cooled TIG torch to prevent the tungsten from melting and improve the current carrying capacity of the torch when welding thicker material.  XXX
Use a pure tungsten electrode and increase the diameter to compensate for additional heat load at the torch. Less than 3/32" thoriated tungsten electrodes are not recommended for welding aluminum.  X  
Consider using preheat on thick sections. Oxy-acetylene torches work well. Be sure to set a carburizing flame and use a temperature measuring device.  XX 
Be patient on arc starts. Aluminum and copper have high heat conductivity. Materials will not melt for several seconds.  XX 
Use a remote foot or hand control to compensate for the high thermal conductivity of aluminum or copper or with thin stainless steel.  XXX
Use Direct Current Straight Polarity (DCSP) electrode negative when possible. Direct Current Reverse Polarity (DCRP) may be used for very thin sections (<1/16").   XX
To improve surface color match and corrosion resistance, use pulsed current settings.   XX
Use an alloyed tungsten electrode to increase current carrying capacity. If thoriated tungsten is selected, ensure all grinding dust is captured and removed from the operator's breathing zone. Consult MSDS of the electrode manufacturer.   XX
To minimize surface discoloration, maintain close nozzle-to-work distances (maximum 1/2" from work piece).   XX
Rapid cool thin sections to maintain corrosion resistance.    X
Minimize heat input while maintaining sufficient penetration.    X