自製電路板 (PCB) 蝕刻液, 氫氯酸 + 過氧化氫 (鹽酸 + 雙氧水)
混合約 1份 [鹽酸] 以及2份 [過氧化氫], 就可以自製一種強力的PCB蝕刻液.
常溫時, 蝕刻 3“X5 的PCB大約需時不到10分鐘.
如果棄置處理嫌麻煩, 可以不斷重複使用這種蝕刻液. 事實上，使用這種蝕刻液, 經過幾次蝕刻後，溶液已經成為 [酸性氯化銅]（見下文）。
HydroChloric Acid / Hydrogen Peroxide
Mixing about 1 part HCl (Which can be found at most hardware stores, also known as Muriatic Acid. Ask for concrete cleaner.) into 2 parts Hydrogen peroxide (normally used for cleaning cuts) you can make a fairly powerful etchant. Use gloves and don’t breathe the fumes though. This will etch a 3″x5″ board in less than 10 minutes. No need to heat it up. I usually like to drill a small hole through the board on a corner and thread a wire or nylon string through to help agitate / remove the board.
When the board is done etching, the etchant will probably look like green kool-aid, from the copper content in it. This stuff is highly corrosive and will burn skin, which is why you should wear gloves. But it is easy to handle, and fairly easy to dispose of. the etchant is easily deactivated with baking soda. Pour enough baking soda into it slowly (to keep it from boiling and overflowing… remember what happens with baking soda/vinegar? ya…) until it is a solid mass, then leave it in the sun to dry. You should contact your local authorities to find out what you should do with it next. Whatever you do, DO NOT dump the stuff down the drain, it will eat through your pipes just like any of the other etchants.
Alternatively, instead of disposing of the etchant, you can re-use it again and again. In fact, after etching a few boards with this solution, you will have successfully made Acid Cupric Chloride (see below).