this doc aims to explain how to make pcbs using the photo etching method on uv sensitive boards

kit list

  • acetate (we have)
  • az303 developer (we have)
  • uv light box (we have)
  • bubble etch tank (we have)
  • ferric chloride 40% premixed (we have)
  • a timer (attached with magnet to shelves above the bubble tank)


using eagle

  • show the layers you need. I used top, pads, vias and dimension for a combo SMT and through hole board
  • print from eagle to laser printer, click the mirror and black box
  • acetate face down in laser printer
  • make sure the print is black enough or you will have problems with the resist - you can try printing twice


  • if you've had to cut the board down, make sure it's flat with a file or you may get uv leaking under the acetate
  • peel off protective cover on the board
  • line up the artwork on the board. You may want to hold it in place with tape
  • make sure it's the right way round!
  • put the board down on the uv lightbox glass with the acetate between
  • set timer for 1.5 minutes, press go
  • If you see pitting in the resultant mask it's because you exposed for too long or the acetate wasn't dark enough


we don't have a slot for this in the etch tank so we do it in a shallow tray

  • put the board in a shallow tray
  • cover with the developer
  • leave for 2 minutes
  • wipe off developed mask and rinse in water


  • turn on the tank and the heater
  • set the thermostat to 4 and wait for heater lamp to go out
  • put board in the mesh holder and immerse in the ferric chloride
  • turn on the bubble pump
  • wait for until etching is complete (at least 3 minutes). timings vary on size of board, temperature and as ferric chloride is used.
  • clean off the mask with acetone
  • resources/bubble-etch
  • Last modified: 3 years ago
  • by felix.h