TIG Welding Aluminum for Beginners: Steps 3 & 4
Editor's note: Andy Weyenberg, Miller motorsports manager, presented four steps for beginning aluminum welders at SEMA 2009. The first two steps/videos are found here.
Step 3: Forming and Controlling the Puddle
As discussed in Step 1, hold the torch by bracing it with the base of your hand (from your wrist to the tip of your pinky finger) flat against the table. Keep it in a steady, forward-moving position with a slight backward tilt (5- to 15 -degree) to the torch. Keep a close distance from the tungsten to the workpiece (typically equal to the diameter of the tungsten up to about ¼ in.).
Without adding any filler metal, establish the puddle and walk it down the piece. Aluminum is a heat sink and gets hot very fast. It’s like driving a car downhill: it keeps picking up speed as it gets hotter and hotter. Hence, it’s always important to monitor the puddle as you move along to keep the puddle width consistent. If it gets too hot, ease up on the foot pedal to maintain a consistent width . When you get to the edge of the workpiece, where there is less alumin um to absorb heat, the workpiece gets hot very quickly and the puddle washes out much faster. It’s important to ease up on the pedal to maintain puddle control. However, if you don’t put enough heat into the puddle, the puddle will disappear, the arc will become erratic, and you’ll do nothing more than etch the aluminum.
The following sequence of photos shows how speed and heat affect the puddle:
Figure 1: Proper puddle width, maintaining speed and distance between the tungsten
and the workpiece.
Figure 2: Moving the torch too quickly along the piece causes you to lose puddle control.
Slow down while maintaining heat input.
Figure 3: Slowing down torch speed too much and adding too much heat to the puddle
causes problems related to excess heat input, as seen in the weld here.
Figure 4: Proper speed, but adding too much heat to the puddle causes you to lose
control of the puddle, as seen here. Find the balance between speed and heat input.
Figure 5: Proper torch speed, but not enough heat put into workpiece causes the puddle
Lay down a puddle like this without filler metal numerous times to practice maintaining speed, distance and the puddle width. Because the piece gets hot so quickly, set it aside and pick up another one before continuing . The hotter the piece gets, the more out-of-control the puddle becomes—why make training more difficult?
Step 4: Introduce Filler Metal to the Puddle
As discussed in Step 2, 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.
The key to adding filler metal to the puddle is consistency. Start introducing the filler metal with a dab and move motion. There is no need for excessive torch movements as the dabbing of the filler metal creates the bead profile. Establish the puddle and add filler metal to the edge of the puddle. As you establish the movement, you can establish your rhythm. As long as you maintain a consistent rhythm combined with steady torch movement and puddle control, you’ll be laying a proper weld bead on aluminum in no time—as long as you keep practicing.
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