> --- In Homebrew_PCBs@yahoogroups.com, "Leon Heller" leon.heller@>
> wrote:
> Try adding some HCl, that should get rid of the sludge. Adding H2O2
> will
> also help, with the HCl it will convert cuprous chloride into cupric
> chloride. Doing that should allow you to use the solution
> indefinitely, if
> you wish. Heating to about 50C will speed things up a lot. I always
> heat my
> FeCl3 etchant by putting the etchant container inside a larger one
> containing hot water.
>
> Leon
>
You can get 40 volume H2O2 (peroxide, hair bleach) at Sally Beauty
Supply without needing a license or whatnot to purchase it. I've been
using it to regenerate FeCl3 for about three years now. I haven't had
to add any acid for a long time. I use a whole 32 oz bottle per 2
gallons of etchant. It seems to etch faster than the original etchant.
Be careful with the H2O2, while FeCL3 doesn't cause burns quickly,
peroxide at that strength will. Always mix outdoors and add slowly,
this creates large amounts of foaming and heat.