It is the standard method for securing corrugated steel deck to the framing of large buildings.
Cold lapping. This is when you drop a ball of weld into the hole, but it never actually melts into the bottom plate. It looks like a weld, but it pops off with a hammer. puddle weld
| Pros | Cons | | :--- | :--- | | Great for thin sheet metal. | Requires access to both sides? No—only the top side! | | Aesthetically clean: The finished product looks factory. | Hidden corrosion: If you miss the fusion, water can sit between the sheets. | | Excellent shear strength: Resists sliding forces well. | Less tensile strength: Don't use it if you are pulling the sheets apart directly. | It is the standard method for securing corrugated
: The intense heat melts through the thin decking and begins to melt the surface of the structural beam or joist underneath. It looks like a weld, but it pops off with a hammer
Those little circles of steel aren't spots; they are puddles of strength holding your world together.
The execution of a puddle weld requires skill and specific equipment, typically a shielded metal arc welding (SMAW) setup or, more commonly today, flux-cored arc welding (FCAW) with a "welding gun."