Step 1: Key to Puddle Control: Hand & Torch Placement
Beginning TIG welders unintentionally make a lot scrap. For example, you may feel a need to strike an arc on a piece of aluminum before ever practicing basic hand placement and control. Don’t, as this is a waste of good aluminum. The first step to working with aluminum is to master positioning of the torch and hand.
Hold the torch by bracing it with the base of your hand (from your wrist to the tip of your pinky finger) fla t against the table. Keep it in a steady, forward-moving position with a slight (5- to 15 -degree) backard tilt to the torch. (Figure 1).
Figure 1: Keep the torch in a forward-moving position with a slight 5- to 15-degree backward tilt.
Keep a close distance from the tungsten to the workpiece (typically equal to the diameter of the tungsten up to about ¼”). If you pull the tungsten too far away from the workpiece, the arc spreads out too wide and overheats the piece and you lose puddle control (more specifics on this topic to come in Step 3). Working with aluminum is all about puddle control and fighting the fact that it acts like a huge heat sink and rapidly transfers heat away from the weld area ( this is why steel is much more forgiving: the heat stays more localized, which in turn makes it easier to control the puddle).
Step 2: Coordinating Movement and Filler Deposition
Without striking an arc, work on the flow of your hand and torch movement. Practice with gloves on as you would in a normal welding situation. Keep light pressure on your hand, a firm grip of the welding torch and slide your hand across the welding table in an even, steady motion. If you don’t move your hand and you just move your fingers, you’ve become a one- or two-inch welder, and there aren’t many applications where that is useful. This practice helps you “calibrate” hand/torch movement and the distance of the tungsten to the workpiece without creating any scrap.
Filler metal deposition takes place ahead of the TIG torch as you push forward. The torch and the filler rod should roughly be in a 90-degree configuration to each other (Figure 2). Always push a torch—never drag it—and always introduce the filler metal on the leading edge of the puddle. One hand is smooth and steady as it slides, while the other hand dabs the filler metal. Practice this without striking an arc.
Figure 2: The torch and the filler rod should roughly be in a 90-degree configuration to each other.
Most beginners have issues, at first, getting their hands working independently. They usually end up moving both hands at the same time: As they attempt to dab the filler metal, the tungsten dips too, which usually results in touching the filler metal to the tungsten and contaminating. Disconnect your hands and brain so that each hand performs its task independently. When you’ve mastered these movements, you’re ready to strike an arc.
(by by Andy Weyenberg, Miller’s motorsports marketing manager, published at www.millerwelds.com)