You probably need to add some brightner to this bath. The brown film
being deposited is called "burning" and is the result of low
brightner, high current density or both.
Most acid copper baths can operate around 30 amps per square foot
with the proper bightner additions. The voltage will be approximately
1.5 volts but can vary depending on the acid content. Do some
research on the "Hull Cell" which is a miniature plating tank with a
diagonal cathode. This small plating cell can be used to trouble
shoot most plating baths. It will show the high and low current
density areas and help determine the proper brightner levels.
A regulated power supply may not be the best way to make a rectifier.
I have always used a "variac" variable transformer controlled
rectifier for plating. This allows to current to be set without the
power supply trying to compensate. The voltage will end up where it
needs to be if the current is set properly. You could try using a
model train transformer for your rectifier or use a triac lamp dimmer
to control the power supply transformer. Maybe some of these ideas
will help.
Tom
--- In
Homebrew_PCBs@yahoogroups.com, "roel_cnc" <atmelletje@g...>
wrote:
> Hi,
>
> I'm trying to get me bath plating but it isnt working as it should
be!
> only thing i got is a dark brown easely wipe of film
> pcb is 10 sq cm power supply gifs 1,8 volts ad 0,7 amps
> also tryt a 5 volt make same result only faster
> have to tell the bath solution is made as adam's style with a
> terracotta pot - acid is pritty blue
>
> gr. Roel