Homebrew PCBs

Grant, I took a 500 ml beaker. Added 20 ml of 8M HCl (20% 
wt) + 20 ml of water and pieces of scrap copper sheet 0.7 mm
thickness. At this stage about 1/2 of the copper was
above the liquid level. Over a 54 hour period I measured the 
progress.


   time    HCl     Cu mass   appearance
(hours) (Molar)   (grams)   of solution
---------------------------------------------
    0      4M       12.3g     clear
   12      ?        ?         pale brown
   23      ?        10.0      Coca-Cola brown
-> added 20 ml of 8M HCl + 5 ml water.
-> started bubbling air through solution.

   23      5.45     10.0      "       "
   34      3.77      3.8      dirty brown liquid
   46      2.4       0.7      dirty brown liquid
   54      1.67      0.0      deep green


Note: The bubbles were created from a air hose immersed in 
the solution. If an airstone had been used to create smaller 
bubbles then the reaction would of been much faster.

regards,

Adam.