[Ben Ardwin] was asked by a friend to help fix an old motor. It needed a new set of brushes. They’re just thin pieces of copper that mount on the motor housing and contact the commutator. The metal is so thin he thought he’d try fabricating replacements by dissolving copper stock.
This is not copper clad board; the raw material used in PCBs that has a copper-covered fiberglass substrate. It’s just thin sheets of copper stock. [Ben] started by covering top and bottom with painter’s tape. This will act as a resist for the chemical etchant. He headed over to the laser cutter to remove the tape mask around the outline of the parts. From there it’s into the Cupric Chloride for about two hours.
The etched parts are a bit rough around the edges so he cleaned them up by hand using a file. When writing to us about the process he suggests a few improvements. The tape used for masking wasn’t ideal and he would try a different method. He would also remove less area around the parts to help speed up the process.
This technique is a really becoming popular as a home-fabrication tool. Recently we’ve seen etched copper used to make a faceplate for an enclosure, and a translucent template for a clock.
