Homebrew PCBs

> places for hanging board holders.  I have some 1.25 inch, 80 psi 
sewer 
> pipe, which is black, not white.  I don't know the chemistry.  I 

White sewer pipe is PVC plastic, the black stuff is ABS, butI don't 
know anything about it's chemical reactivity.

>   I got 2 gallons of hcl for $5 at home despot, and a quart of h2o2 
for 
> a buck at Savon.  Now all I have to do is use the stuff.

I'm guessing, but is that Savon drug store? So this H2O2 is the 3% 
medical grade?

>   I've looked around some, and never seen any sites that say 'use 5 
> parts hcl to 1 part h2o2 to 9 parts h2o', or whatever.  Does anyone 
know 
> what the final % hcl and h2o2 the solution should start with?  I've 
seen 
> how to keep the cucl2 going, but not how to start it right.
> Thanks,
> Richard

Others will reccomend using stronger H2O2, 30% or 50%. But I had a 
hard time finding it without paying extremly high hazmat delivery 
fees, so I experimented with using the weaker medical grade.

My acid (HLC, or Muratic) is bottled at 31 point something percent 
strength. From what I've read you want between 10 and 15% in the 
final etchant. Generaly that's accomplished by diluting the acid 50-
50 with water and then adding up to a couple ounces per gallon of 30% 
H2O2.

I have successfully used 2 parts 3% medical H2O2 with one part 31% 
acid - no additional water. It's pretty close to the same mix when 
you're done. Etching times of 7-10 minutes.

With stronger H2O2 (30% or more) you can just add a little more to 
regenerate the mix. With the 3% stuff it has too much water and if 
you add enough to regenerate the CuCl it dilutes the mix to much. To 
get around that I usualy just regenerate with a bubbler. (aquarium 
pump and a plastic "air stone")

By the way, I use a rubbermaid 5161 ceareal keeper as an etch tank: 
http://tinyurl.com/3hbax About $5.50 at Walmart, holds a gallon and a 
half and can do a 9x9 inch board nicely. For a holder I usualy just 
dangle them on a piece of plastic coated wire (cat5). Mostly just 
loose loops around opposite corners, but sometimes I drill a hole in 
the corner.

-Denny