Ron Amundson wrote:
> I need to dig up the data sheet for a better explanation, and I'll post it
> later.
>
> I am howver interested in your findings with ferric chloride. I've got some
> around here as well, and as you stated its shelf life is a real advantage. I
> however have never been able to acheive decent etching with it. I've tried
> room temperature, 50 deg C (122 deg F), agitation and aeration, and have
> always had problems with non-uniform etching. Part of the board gets over
> etched, and yet another section 10mm away will be under etched.
>
> A typical board for me is about 50mm x 50mm (2.5inX2.5in) with around 40-150
> SMD components with 0.012 to 0.025 traces.
I only use ferric chloride. Normal double-sided 1oz Cu pcb etches between 5mins
for new solution, and 12+mins for old solution when i ditch it. I dilute it 1:1
with water, add a bit of hudrochloric acid every few months, and use it at room
temperature with some bubbles (small air pump). It is important to clean and
degrease the copper before putting any artwork on it. That's likely your
problem.