by Jason Becker
Many people are intimidated when it comes to thin gauge stainless, especially when you get out of position. Stainless welding will take some practice, especially on thin material. The biggest problems you will run into are burning through and sugaring.
Sugaring occurs when you overheat the material and the backside of the plate is unshielded and reacts with the open oxygen in the environment. There are a couple things you could use to prevent that, one is a chill block, take a thick piece of copper, brass, or aluminum and clamp it to the back side of the piece. This will do two things for you, one it will act as a heat sync but will also prevent the oxygen from interacting with the piece. Another thing you can do is to use a gas block on the back of the piece. This will keep the backside shielded with Argon and keep oxygen out of the area. Lastly, you can increase your speed so that the joint doesn't get too hot., Increasing travel speed will decrease the heat input.
The main thing to focus on is stability, I always recommend maintaining 3 points of contact. For this demonstration, I propped up on the workpiece using a TIG Finger. The more stable, relaxed and comfortable you are, the better your weld will turn out. TIG is very intricate work and if you move the wrong way even slightly, it will appear in the weld. I also recommend doing a dry-run (move across the joint without welding) first to make sure you have enough range of motion to complete the weld. Doing a dry run will tell you if you need to reposition your self or possibly plan out a stopping point. Either way, its a good practice and after 20+ years in the
welding industry, i still do dry runs on most weldments before actually welding them. If you cant brace yourself on the material, you can try resting the cup of the TIG torch in the groove, this is a very common practice, but you need to make sure it is allowed. In some chemical and food grade work, resting the cup is prohibited because the cup can actually scratch the parent material and cause a rejection of the piece.
In conclusion, always ensure that you are comfortable while you are welding, your welds will turn out much better and more consistent if you are stable and comfortable. Until next time, Make Every Weld Better Than Your Last.