I’ve done both chemical (ferric chloride) and electro-etch and favor
the electro-etch technique.
The electro-etch is much less mess, no chemical disposal. You can
buy a DC power supply or you make you own DC power supply from an old
cell phone or some other DC charger (which what I did). You can even
use a 9 volt battery or a series of D cell batteries.
If you go the cell phone charger route, look for charger with an
output of about 10 volts and 1 amp. The voltage/amperage can vary a
bit: voltage ± 2 volts and the amperage ±.5 amps.
You are able to vary the depth of the etch by by time and distance
between the anode and the cathode.
Although a longer etch time loses crispness.
The anode is the positive side and is connected to the item to be
etched. The cathode is the negative side and is connected to a piece
of metal (generally copper) that attracts the copper ions. The
cathode will acquire deposits of the copper ions.
Both the anode and cathode are suspended in an solution helps the
flow of the copper ions.
For copper/bronze/brass/nickel silver I use copper sulfate
pentahydrate (aka Root Kill). I make a solution of 1 liter of
distilled water to 200 grams of Root Kill. You can use this solution
forever (it turns a nice blue color over time). All I ever do is top
off the solution with distilled water as it evaporates.
This same technique can be used to etch fine silver or sterling
silver. In lieu of the Root Kill, cupric nitrate. I brought mine from
the The Science Company on-line. A nice feature of etching silver is
that the silver precipitates out so you can recover the silver.
A word of caution: This process is using electrolysis to charge the
copper. You’ll see bubbling on the anode, this the water being broken
into oxygen and hydrogen. I’ve never had any problems, but I
wouldn’t use near an open flame (about 3 feet).
Please contact me with any questions.