There are two main types of etchant. Ferric chloride and ammonium persulphate, we are going to use ammonium persulphate since it is clear and easier to show the etching process. It comes in a power form and needs to be mixed with water. Since we are not using the entire bottle we will use a scale to measure the correct amount.
There are lots of cool red labels on the bottle… Make sure you have your rubber gloves and splash goggles on! This process should be done in a well ventilated area. Fill the correct amount of warm water into a plastic container and slowly pour the ammonium persulphate in. Make sure it is being mixed as it is being poured in.
Place the board into the etchant and agitate the container to keep the etchant flowing over the board. This step will remove the exposed copper, the copper that is under the coating (resist) should be protected from the etchant and remain.
Keep a close eye on the progress; once the copper is removed you will see the fiberglass board that is under the copper.
Rinse the board in some cool water, wash well to make sure all of the etchant has been removed. Note the picture here is actually from rinsing the develop mixture off the board. Wear gloves when doing this.
This is what you should now be left with, a board that still has a protective coating (resist) on the copper, and other areas where the copper has been completely removed.
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