I think there are many reasons that ferric chloride is still used so
commonly. It's the "done thing". If you just ask around most advice
about making PCB's will be to use FeCl. And it is readily available,
as are the persulfates which can also be used to etch.
The CuCl approach has several advantages - it is cheap, after the
initial investment for equipment (and maybe chemicals - the mail order
source I found in Canada for CuCL wants $175 for a pound!) and cupric
chloride is very environmentally friendly, since you don't have to
throw out the solution, just top up the hcl from time to time. But for
this you need some lab equipment to do titration, and some bromalin
orange indicator. All this is new and different for most amateurs, the
chemical equipment is not easy to find in the corner store, and it
costs some money when you do track it down. While hcl is readily
available from Home Depot or pool supplies, at the concentrations sold
(28% here in Toronto) it is much more dangerous than fecl or
persulphate. Acid proof gloves and goggles are wise. You need to find
an effective way to generate air bubbles evenly to get a reasonably
even etch. Think and Tinker (IIRC) outlines a good approach with PVC
pipe, but this takes time and tools). To speed etch times, you need
heat. To heat the solution requires a quartz covered heater element,
again not a home depot item, although available cheaply from surplus
sources sometimes. You also need a container to hold the cupric
chloride etchant (the original web article suggests using a plastic
picnic cooler, which is cheap and easily located) but if you heat the
solution I think there can be some hcl fumes which you need to get rid
of without acidifying your work environment with fumes. Do you need a
fume hood? Where do you find an acid proof fan? Where do you safely
vent hcl fumes without corroding neighbors or homes?
I hope to use this approach, but it is not as simple as buying some
fecl and adding water in a plastic container. The benefits are worth
the costs as far as I am concerned, but IMHO its not quick and easy to
get started.
Grant
--- In
Homebrew_PCBs@yahoogroups.com, "rolanyang <rolan@h...>"
<rolan@h...> wrote:
> I had a chance to play around with some CuCl2 (Cupric Chloride)
> etching last Friday and performed a test etch {snip]
> I can't imagine why people are still using Ferric Chloride.
>
> ~Rolan