Hackaday reader [David] was looking for a cheap and easy way to spot weld copper tabs together. As he notes in his writeup, the properties of copper which are most enticing, such as high thermal ...

2 Resistance spot welding A method of spot welding of two metal plates by overlapping them, and applying pressure with a copper electrode while passing a large current through them to form a molten ...

But high electrical conductivity also means that copper has high thermal conductivity, which makes welding difficult. Any laser heat that is applied to a specific spot quickly transfers through to ...