Homebrew PCBs

On Sat, 02 Oct 2004 07:55:29 -0400, Anthony Toft <toftat@...>  
wrote:

>
> I am going to be mixing a batch of CuCl etchant today using the recipe
> found on the group site. Basically 2:1 3% peroxide:Muriatic Acid. I have
> read that I should 'preload' this with some copper, is it necessary?
>
> Also would a used soda bottle be suitable storage for the results? As I
> think the etchant will work more than once right?

You shouldn't store it airtight with oxygen left, it might explode the  
bottle.

preloading: no good with that, you have H2O2.

The trouble is 3% H2O2. you can't use it to regenerate the etchant, it has  
too much
water. this seems like a one-time recepie. With a lot of luck, and a LOT  
of patience
you might be able to use a bubbler and add enough copper to make it a CuCl  
etchant.

It is definitely easier to use 30% H2O2 and let it "grow" into CuCl on  
it's own.

Long-term storage: a plastic bottle showed funny salts on the outside  
after some time(years).
(same with pure HCl) so i use a glass tank and a glass bottle for excess  
etchant.


ST