The weld puddle is the molten area of the base metal that forms directly under or behind the heat source (the rod, wire, or torch). It is the liquid state of your final weld. If the puddle is the right size and shape, the resulting cooled bead will be strong and uniform. How to "Read" the Puddle
Once the heat source moves away, this molten pool cools and solidifies to form the final weld bead. puddle in welding
| Problem | Visual Cue | Root Cause | Correction | | :--- | :--- | :--- | :--- | | | Drooping bottom, convex bead. | Excessive heat or slow travel speed. | Increase travel speed or reduce voltage/amperage. | | Puddle too small / ropey | Narrow, tall bead with poor wetting. | Insufficient heat or fast travel. | Slow down or increase heat input. | | Undercut | Groove melted into base metal next to puddle. | Travel speed too fast, or arc too long. | Slow down, shorten arc length, pause slightly at edges. | | Porosity (pinholes) | Bubbles freezing on puddle surface. | Contamination (oil, rust, moisture) or gas loss (GMAW/GTAW). | Clean metal; check gas flow (20-30 CFH typical). | | Slag covering puddle (SMAW/FCAW) | Puddle hidden under liquid slag. | Normal for these processes. | Watch the slag-puddle interface —the solidifying line at the rear. | The weld puddle is the molten area of
Reading the puddle means observing its behavior to make real-time adjustments to your technique. How to "Read" the Puddle Once the heat
Learning to "read" the puddle allows you to make instant adjustments to your heat, speed, and angle. Professional resources like Miller Welds emphasize that the puddle is the welder’s primary feedback loop.
In the world of welding, the most critical skill an operator must master is not the settings on the machine, but the ability to read and control the .
: In processes like TIG, the puddle should look like a clean, shiny pool of liquid silver. If it looks "cloudy" or has swirling black specks, you likely have contamination (e.g., dipping your tungsten into the pool). Techniques for Puddle Control Stick Welding: How to Read the Puddle