How To Correctly Weld Stainless Steel
A cool modification lots of people do is TIG weld a custom stainless steel exhaust system. The problem is that stainless steel can be a difficult material to work with due to its chemical makeup.
Stainless steel contains higher amounts of carbon and chromium than mild steel. That’s what gives it its shiny appearance and corrosion resistance. The trouble starts when you try to heat the metal to weld it, the carbon and chromium want to rise to the surface of the molten puddle. When that happens the elements will react to the oxygen in the atmosphere, oxidize, and contaminate your weld.
Start by correcting your heat. A good rule of thumb is to use 1 amp of current for every thousandth of material thickness. You also want to try and move fairly quickly so the material doesn’t get quite as hot.
You can also adjust the gas coverage by swapping out the stock #7 cup to a larger #12 gas lens. That gives you a larger shielding area, directs the argon smoothly onto the weld, and keeps the hot molten steel protected longer. You will have to turn up the shielding gas flow but the rest of the settings can remain the same.
At the end of the day, like with anything else, practice makes perfect!