Warning In this experiment corrosive acids are used. Gloves should be worn. Greetings fellow nerds. I’ve gotten a lot of requests for this so in this tutorial we’re going to make ferric chloride. A useful chemical to etch copper clad printed circuit boards. Start with 20g of iron. I’m using iron nails but steel wool also works. Just use whatever iron source is cheaper for you. Now add to it 100mL of water and then add 100mL of concentrated 12M hydrochloric acid. The acid should start dissolving the iron. This can take a couple of days if you’re using nails.
Steel wool dissolves within a few hours but if you’re impatient like me you can speed up the dissolution by heating up the mixture. I’m going to put this round bottom flask of cold water on top to recondense any vapors. And there it goes. Obviously if you’re going to boil acid do this outside or in a fume hood. What’s happening at this point is the iron is reacting with the acid to produce hydrogen gas and green iron II chloride also known as ferrous chloride. Once the iron is completely dissolved turn off the heating and let it cool.
If any of the acid evaporated or boiled off just top it up with more acid until the total volume is back to 200mL. Now with lots of stirring slowly add 200mL of 3 hydrogen peroxide. Do this in small portions since the mixture will heat up a lot. If it gets too hot to hold slow down and wait for it to cool before adding the rest. What we’re doing here is oxidizing the ferrous chloride into iron III chloride, better known as ferric chloride. If you don’t want to use hydrogen peroxide.
Then a cheaper way to oxidize it is to bubble air through the solution using an aquarium pump. Okay I recommend using something a bit stronger than this pathetically weak pump but it will still work. Over the course of several days the oxygen will slowly react with the ferrous chloride to produce ferric chloride. This also has the added advantage of keeping the solution more concentrated than the hydrogen peroxide method. Of course the hydrogen peroxide method is faster if you’re impatient. Anyway, however you oxidize it, it’s now ready for etching printed circuit boards.