By André Odermatt

Welding is melting and fusing together two pieces of metal to form one perfect union.  People’s safety depends on trillions of welds.  Welding holds together much of the industrialized world.  Welds are used in automobiles, airplanes, bridges, buildings, pipelines, high pressure tanks and more, much more.  

Metal transfers from a consumable electrode across an arc to the base metal.  A liquid weld pool is created through the interaction of a concentrated heat source and the parts to be welded.  The metal transfer is accomplished in various forms depending on the process chosen and many other variables.  Once the molten consumable droplet hits the base metal, it becomes part of the weld pool, commonly called the “puddle”.  The puddle is the most important element in the dynamics of the welding process.  The puddle, as it travels along the joint, has a short lifetime as it quickly cools and solidifies and becomes the weld bead in fractions of a second.

The weld bead is the puddle, frozen in time; it becomes instant history that can not be changed.

The puddle is the single most important factor to form a perfect union between parts to be welded together. It is the root cause for a weld to fail or to pass, for a beautiful weld, or for a mediocre weld appearance.  It is for this reason that Hobart Institute of Welding Technology (HIWT) training methodology stresses the importance of learning how to read the puddle.

A child first learns how to read and then reads to learn.  Once the HIWT student has learned how to read the puddle, he or she will then be able to read the puddle to learn how to master the puddle so it behaves as the welder wants it to behave.  Arguably, most self-taught welders are still learning how to read the puddle.  Defects such as incomplete penetration, lack of fusion, undercutting, inclusion of impurities, porosity due to gas entrapment and cracking, all have the root cause in the puddle.  HIWT graduates have become smart welders and have proven that by passing over 30 AWS tests that verify they can master the puddle. However, to form a more perfect union, welders must continuously strive for the perfect weld by consistently being able to master the puddle in many different situations.    

Our goal at HIWT is to instill in our graduates a confidence and pride in their work so that they never tire of trying to attain that perfect weld and that they never stop learning.