TIG welders know that welding highly reactive metals like titanium or molybdenum, or welding stainless steel, or working in high purity welding environments in industries like aerospace, food processing, dairy, and medical devices, that one of the most common causes of contamination in welds is oxygen. In fact, this is why TIG welding torches flow argon over the weld zone—argon is a heavier gas and displaces the oxygen and allows the weld to cool properly. This is why we have accessories like gas lenses and wide TIG cups, and highly engineered TIG torch trailing shields—to ensure proper shield gas coverage.
So even if you think your weld is protected with a nice big Gas Saver lens there are other ways that oxygen can enter the weld zone. Turbulence can actually pull oxygen in from the atmosphere surrounding the weld zone and can be caused from an improper flow rate setting—this is a case where more is not necessarily better.
Once you’ve determined the proper flow rate for your specific weld, you’ll want to use a Welding Flow Meter to ensure the proper flow rate, and a Shield Gas Flow Tester to measure the actual gas flow at the torch.
You also want to make sure your equipment is in good working order. Check all your gas connections and supply hoses.
Remove the back cap from your TIG Torch and check the o-rings. They can easily dry out and crack, creating an entry port for oxygen. Besides it’s a dollar repair–well worth the trouble.
Also, check the torch insulator while you’re at it, and make sure all the parts are well seated and fit properly.
Note: Arc-Zone.com has all the replacement parts you’ll need for your TIG Torch, and handy graphics (like the one below) so you’ll know exactly what you need:
Welders who are new to Titanium welding may not realize that the recommended gas hose set up is not a rubber hose, but rather a vinyl one. Arc-Zone will be launching a specially manufactured hose for high purity TIG welding (you can read about it over on CarmenElectrode.com). You can special order one by calling Arc-Zone at 800-944-2243.
In the meantime, use your vinyl hose. Rubber can absorb moisture and oxygen and deliver it to the weld zone.
“The Right TIG Torch Hose for your High Purity Welding application”
“Know your TIG torch: advice and maintenance practices to ensure quality”
“A shielding gas primer for GTAW: gas selection and optimization”