You'll need the following ingredients:
- laser printer/photocopier & transparencies (I go to a print shop to do this)
- copper board (local electronics store)
- scrubbing pads (SOS or a generic brand is perfect)
- rubber gloves (like the ones you use for washing dishes)
- Ferric Chloride or Ammonium Persulphate (local electronics store)
- drill and drill bits
Step 1: Design and print
Step 2: Transfer the toner
Clean and rinse the board with the scrubbing pads and soap. Dry it up. Place the transparency on the copper board, place a piece of paper on top if it all and start ironing! Depending on the size of your circuit, it takes about 2-3 minutes for the copper board to get hot enough so the toner sticks to it. When you think you're good, immerse the copper board (with the transparency stuck to it) in cold water. Then you should be able to peel off the transparency while the toner remains on the copper board.
If the toner did not transfer completely, you didn't iron long enough and/or didn't set the temperature high enough. If the toner transfered but is smudged on the copper board, the temperature was too high and/or you ironed for too long. You can use a Sharpie or any other permanent marker to fix parts of the circuit that did not transfer properly.
Step 3: Etch
Step 4: Clean
You can reuse the etching solution, so just pour it back in the original container. Do not pour it down the drain! It will corrode your copper pipes... Over time, the etching process will take longer and longer. When the solution becomes unusable, contact the waste management organisation in your community to know where to dispose of the chemical.