Homebrew PCBs

Hi Phil,

This describes the whole process with cupric chloride:  http://members.optusnet.com.au/eseychell/PCB/etching_CuCl/index.html

I have been using it for several years.  Too much acid leads to undercutting, but the amount of acid is difficult for most DIY'ers to access.  Go by specific gravity and color.

John
  ----- Original Message ----- 
  From: Philip Pemberton 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Monday, March 19, 2012 4:39 PM
  Subject: [Homebrew_PCBs] Rejuvenating ferric chloride etchants (was: Darkening laser printer toner?)


    
  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@...
  http://www.philpem.me.uk/


  

[Non-text portions of this message have been removed]