On Jan 10, 2007, at 12:52 PM, Stefan Trethan wrote:
> Now you should look into care and feeding of this etchant as CuCl.
> You can
> use it forever only replenishing small amounts of HCl and regenerating
> with H2O2. You will want to get H2O2 in high concentration (above
> 20%), or
> you'll add too much water.
> How to maintain CuCl can be found in the links section, although many
> guides make it way too complicated.
> If your etchant was fuming or bubbling you probably had a much too
> high
> concentration of one or both of the chemicals. CuCl will not cause any
> smell, or cause any rust to nearby parts, if the concentrations are
> within
> reason and it is covered when not in use.
Last year I learned about Electrolytic Rust Removal.
To sum it up, you can add baking soda to water, drop a rusty piece of
metal in it attached to one lead from a battery charger, and put in a
piece of scrap metal attached to the other lead from that battery
charger.
By forcing electrons into the 'salt' solution you have created, the
rust on the metal you wish to reclaim is neutralized and falls off.
This process also destroys the scrap metal, causing it to rust away
within a few days until there's nothing of it left.
The piece of metal you wanted cleaned, however, comes out of the
'salt' bath with the rust turned black and falling off.
I bring this up because I wondered if the process could be used to
recharge etchant. If you put a copper rod in as the sacrificial
scrap metal, you'd force copper into the solution.
William Carr
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