How to Etch a Circuit Board

A circuit board makes checking connections easier than going through a tangle of wires and parts to find the right point to check with a ohmmeter. The circuit is kept tight and in one place by being confined to the circuit board. You can follow the traces on the board. These are mostly used by manufacturers for the products they sell, but home inventors can make them easily also.

Instructions

Difficulty: Moderately Challenging

Things You’ll Need:

• Pre-coated photo-resist fiberglass board
• Exposer, UV light source
• Etchant solution, ferrous chloride
• Etchant tank
• Rinse tank, water
• Methanol or isopropyl alcohol
• Pre-checked and tested circuit design
• Tape

1. Draw your circuit out on paper and build a breadboard design of it. Thoroughly test the circuit to make sure that it performs as you desire. Once the circuit has passed a rigorous testing phase, you are ready to commit the circuit to a printer circuit board.
2. Use a computer aided drawing program or your own hand to draw the circuit on paper. Take the paper and have a transfer transparency made from it with the darkest setting on the photocopier. The darker the copy the better the traces on the circuit board will be.
3. Tape the transfer transparency to the copper side of a pre-coated photo-resist fiberglass board. Expose the board to UV light coming from an exposer. The exposure time should be between 2 and 8 minutes depending on the strength of the light source in the exposer.
4. Place the exposed board in the etchant solution. This will remove all the copper from the board except where the traces were on the transparency. The board may take as long as an hour to develop depending on the degree of agitation of the developing tank, the temperature and the freshness of the etchant solution.
5. Wash the finished board with lots of water and finally with either methanol or isopropyl alcohol. This will clean any oils or chemicals that remain on the board.