On Mon, Sep 13, 2004 at 04:24:43PM -0700, William Chops Westfield wrote:
> On Sep 13, 2004, at 9:03 AM, Philip Pemberton wrote:
> 
> >Hardly surprising. That's a "piranha mix". I'd be VERY surprised if you
> >managed to make CuCl etchant out of it - it degrades pretty quickly.
> >How did you convert it into CuCl? Just dump a load of copper into it 
> >to get
> >rid of the free chlorine?
> >
> I think it has a lot less H2O2 than real piranha etchant, and probably
> less acid as well.  But yes, you keep adding copper (and air) till you
> get a nice deep green solution that starts to precipitate CuClO, and
> then add a bit more acid.  At least, that's what I did.  You only need a
> little, relatively weak H2O2 to get started.   The easiest copper to add
> is scrap stranded copper wire, but copper tubing and such will 
> eventually
> dissolve as well.

This thread has defintely peaked my interest. First a recap, then questions.

Procedure:

1) Mix 2 parts 3% hydrogen peroxide with 1 part 32% hydrocloric acid, in the
form of muratic acid from the home improvement store. 

2) Add stranded copper to dissolve in the solution.

3) Bubble with air to add O2 to the mixture to get stable CuCl etchant.

Questions:

1) Is the above procedure correct?

2) chem question: does it matter how the HCl and H2O2 are mixed? In some 
mixtures one reagent need to be stirred into the other. Is that the case here?

3) Are all plastics etchant safe? So bubbling air in a plastic tube is 
sufficient, right?

4) We all know that FeCl must be heated to be effective. Is the same true for
CuCl?

I'm sold on this. It's ultra cheap, can be made with readily available 
components and can be reconstituted with the cheapest component of all: air.
It's clear too right?

I'm ready to go and make a batch today. But I'll wait until I get answers
to my questions.

Man, I don't see how I'd function without the PICLIST.

BAJ
_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist