Handheld laser welder - GIF

[Inner]

For about $8K, it can be yours.

https://cnptengineering.com/handheld...-p00107p1.html

[high-side]

[CanBeDone]

You want one? Google for "Handheld laser welder" and you'll find heaps of them, starting at a few thousand dollars apiece.
You got that kind of cash to burn? I 've got a project for you:
Take a little 3D printer and replace its printing head with the laser. Add some wire feed (for 0.1..0.15mm diameter wire) so that the laser can melt it, and you've got a 3D printer capable of printing steel.
Add ultrasonic levitation (google "ultrasonic levitation") and you can build even more complex structures.
Anybody out there to try it?

In case you are skeptical: previous attempts to do 3D printing with steel used a MIG welder as power source. It worked, but the welder is simply too powerful and resolution was restricted to 3-4mm - not very interesting. Because a laser can easily be operated pulsed, overall (average) power can be turned down much further, allowing the printed structure to stay cool. But local power (i.e. power of an individual pulse) can be high enough for proper local melting, to ensure integrity of the welded structure. Ultrasonics adds the ability to forge your structures even thinner - if you can find or build transducers of the right frequency and power.