Below are the results from submerging copper-clad boards with resist patterns in a ferric chloride acid bath. I've chosen to etch only the acrylic and polyurethane portions of the board from the initial resist materials test plate (see part 1).
This first plate is the polyurethane resist. The portion of the board that's etched is the portion that's been cleaned with alcohol after going through the laser. When the urethane is removed by laser etching it leaves a fume on the surface of the metal that cleans up with alcohol. Looking at the result of the acid etch however, reveals that the fume was not entirely removed around the channels and they seem to bleed out and in some places connect.
This second plate is the result of acid etching the acrylic resist. Once again the fume left by the laser when burning the acrylic blocks the acid from effecting the plate, but in the region that's been wiped with alcohol we're getting a clean etch without any bleed. There are a few areas on the board however where the acrylic fume didn't wipe away as easily and the edges aren't as sharp. More cleaning and perhaps other solvents may improve the fume cleaning step.
