Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Hi guys,

I use Ferric Chloride for my etchant, I know there is "neater" stuff
out there, but this works okay for me - plus I have a couple more
bags of the stuff to use up.

I have a couple questions regarding useage of it...

1) I don't know why I started doing this, but, before etching a
board, I stir up all the muck at the bottom of the tank. Then I drop
in my bubble rock and etch my boards. Is the mucky stuff at the
bottom the Ferric Chloride crystals or is it just useless muck? If
I don't have to stir it up before use - that would save me a bit of
messy work.

2) I have lost count of how many boards I have etched with the batch
I am using right now. If I were to guess, I would have to say
probably in the area of 20-25 8" x 10" boards. Most of those board
were single sided and all copper removed except for the traces and
pads. It currently takes about 20~25 minutes to etch a board with
the chemicals at around 68 degrees F. To be honest, I have no idea
how long it took when I first mixed up the batch :-) So, I am just
trying to get a feel for the "Status" of this batch as to whether
it's time to dump it or keep using it?

3) I know that for some chemical etchants, you use heaters to speed
up the process. I recall someone telling me not to use a heater
with Ferric Chloride so I never did. However, I did buy a fish tank
heater, but never used it. I don't mind waiting 20 minutes to etch
a board if it is safer than doing it faster with the heater. If a
heater is okay to use with this stuff, at what temperature should I
shoot for? (SAFELY!)

Thanks guys!

Chris