Homebrew PCBs

On 19/03/12 08:00, Russell Shaw wrote:
> On 19/03/12 12:18, Leon Heller wrote:
>> If it's dark green, it's probably exhausted.
> 
> If it's dark green, it will etch perfectly well using a different chemistry if 
> you use bubble agitation, and add a bit of hydrochloric acid from the hardware 
> shop every few weeks.
> 
> I get full etch in 10-15mins at room temperature like that.

Well, I've just filtered the etchant through a piece of kitchen roll (my
first choice was coffee filter paper -- I didn't have any, so I figured
kitchen roll would work as an alternate).

I ended up with a green liquid, and brown paper...

So I think it's a fair bet there's some kind of copper salt in the
solution, along with a tiny bit of iron (it's got a yellowish tint to it).

I've thrown in 200ml of brick cleaner (10% HCl, ~£10 for five litres
from B&Q) and set the valve on the air pump to full. Right now I have
foamy green etchant... I'm going to leave it for an hour or so and see
what happens when I throw some FR4 board offcuts in (lord knows I have
plenty of those after last night's complete abortion of a PCB etching
attempt).

This should be interesting...

Thanks,
-- 
Phil.
ygroups@....uk
http://www.philpem.me.uk/