When you’re making a custom circuit board, you’ve got a few options. You could of course attempt to solder things yourself with a perf board, or take the time and lay things out as a PCB. From here though your options are to use a photoresist etching process, mill with a small CNC router, or send it off to a board house. These all have their disadvantages, perhaps most notably that the photoresist etching process is quite involved, and board houses, while producing beautiful results, require at least some degree of waiting.
A new method, developed by hacker “Harbingerx81” uses a 40W laser to selectively burn off paint, exposing copper that is then removed. First the board is coated in several layers of black spray paint and allowed to thoroughly dry, and when the laser process is finished, it’s etched in ferric chloride. After cleanup, you can return to the laser to have it cut out the holes that were formed by the etching process in the copper but don’t go through the entire board.
While you still do have to deal with chemical etchant, this method is much faster and simpler than having to deal with a normal photoresist process. You’ll need to wait for the paint to dry initially, but if you know you’re going to be making circuit boards, you can simply keep a few blanks in stock!