Examine the board for obvious errors. You can fix broken traces by filling in the gaps with a permanent marker such as a fine-tipped Sharpie. Use a hobby knife to separate any traces that have smeared together. Take the time to do a good, thorough job with this step, which can make or break your final product. For this reason, it’s smart to print several designs, rather than pinning all of your odds on one.
The chemicals used in etching are corrosive, and their fumes are irritating. Follow proper safety procedures, wear a mask (or work in a well-ventilated area), and protect your eyes.
There are different types of etching chemicals: dry and liquid. Dry chemicals are less expensive, but require dilution, as directed on the packaging. For this project, we recommend ammonium persulfate, available at lab and electronics supply stores. You will need about 1 quart of etching solution (etchant) to etch a 6" board.
Etching time is related to temperature. A small increase in temperature drastically reduces the time needed to etch a board, but too high a temperature makes the etchant too aggressive and gives off fumes. Aim for a temperature of around 125 degrees Fahrenheit (52°C).
Design houses have temperature-controlled etching tanks. For etching at home, you just need a stove, a large pot, and a plastic tray for the etchant.
Fill the pot halfway with water and heat to a simmer, but not a boil.
Put the PCB in the tray and place the tray on the simmering pot. Then slowly pour the etching solution into the tray.
The steam from the pot will slowly heat the etchant and increase the rate
Etch the PCB on the stove.
Etching in progress.
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