>its the fact you are clearing the copper surface
>from the byproduct produced by the chemical reaction
There has to be relative motion between the copper surface, spent
etchant and fresh etchant for this to be effective. A spray etcher
makes this patently obvious. An analogy would be cooling/heating by
convection means. Your brush, the bubbles and some form of
pump/nozzle arrangement in the case of the spray etcher would be
analogous to a fan, moving spent etchant away from the surface and
at the same time moving fresh(er) etchant in its place.
This movement can be accomplished using self contained fluid
dynamics by rocking the container, agitation or even possibly
ultrasonics. A blender would be an example of severe agitation.
Your problem here seems to be that you're hell bent on "selling"
your method of etching which I've certainly tried and still use for
developing. It's inconvenient and messy especially if you're using
the brown stuff. An analogy would probably be the manual versus
automatic transmission in autos. The AT probably has only one thing
going for it, ease of use, but that's enough to make it the hands
down choice for most drivers here in the US. Even with soaring gas
prices, don't expect to see any change in habits anytime soon.
--- In
Homebrew_PCBs@yahoogroups.com, "Herbert E. Plett"
<cachureos@...> wrote:
>