Saheen Palayi laser-cuts functional PCB solder paste stencils from aluminum soda cans using an xTool F1 Ultra fiber laser. The material is free, the fiber laser's wavelength cuts thin metal nearly instantly, and the hole pattern exports directly from any PCB design tool. This is faster than etching and more precise than machining, the two methods hackers have historically used on can stock.
The hard problem is not the laser cut. It is getting a clean, flat sheet of aluminum without kinking the 0.1mm-thick walls. Palayi solves this with a 3D-printed can-cutting jig that works like a pipe cutter: a utility knife blade section presses gradually into the spinning can until it severs cleanly. Tops and bottoms come off without deforming the cylinder, then one straight snip opens it flat. The build details on that jig alone are worth reading the Instructables post in full.
Fiber lasers cost thousands a few years ago and lived in industrial shops. The xTool F1 Ultra is a prosumer unit available online now. Palayi previously used the same machine to fabricate PCBs by ablating unwanted copper down to bare traces. Solder stencil production is the cheaper, faster application. If you have the laser, the only remaining cost is a soda can.
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