Inside a Welding Molten Pool at 480 fps
The arc strikes and a molten pool forms — metal flowing in real time. As the torch travels, the pool freezes into a clean, rippled weld bead.
What you see
- The molten pool forming as the arc strikes.
- Pool geometry and symmetry tracking the torch in real time.
- The freeze front turning liquid metal into a rippled bead.
- Arc glare filtered out so the pool itself stays readable.
Captured with Therness
- PoolDrop mounts torch-side and films up to 1440 × 1080 px at 240 fps, or 480 fps in high-speed mode.
- Integrated laser-safe lighting suppresses arc glare without extra optics.
- HeatCore AI scores pool geometry and flags anomalies live.
- Frame-accurate evidence for ISO 17635 visual testing and root-cause analysis.
About this clip
A weld pool is a millimetre-scale bath of liquid steel held together by surface tension and stirred by arc pressure, electromagnetic force, and Marangoni flow driven by the temperature gradient across its surface. Its shape is not cosmetic: a pool that stays too shallow means the arc never fused the joint root, while one that grows too wide and deep is on the edge of collapsing through the plate. Behind the travelling arc the trailing edge cools through its freezing range and the solidification front sweeps forward — and it is the rhythm of that front that stamps the familiar ripples into the finished bead, each ripple a brief pause in the balance between heat in and heat out. At 480 fps that whole sequence, invisible to the eye and smeared by a standard camera, resolves into distinct frames. It is the same geometric and freeze-rate signal a monitoring system uses to judge penetration and stability while the weld is still being laid — the practical side of reading the weld pool at 480 fps, not hours later under a microscope.
