On Fri, 11 Mar 2005 11:33:42 -0500, Earl T. Hackett, Jr.
<
hacketet@...> wrote:
>
> The objective in any etching system is to replace the spent etchant at
> the
> surface of the board with fresh. The speed of the etchant moving doesn't
> contribute to the etch rate other than to bring fresh etchant to the
> surface. Friction between the etchant and the board surface makes this
> quite difficult. This is why spray etching is the best - if you have
> enough
> of the right spray nozzles to produce a uniform spray pattern. In a
> spray
> etch 1 oz copper foil will etch in a little over a minute. If you look
> inside you'll see why. The etchant is rushing over the board surface at
> about a thousand feet per minute. In a bubbler system your lucky to get
> to
> 50 feet per minute. In an ultrasonic cleaner there is almost no
> movement so
> all the etchant does is sit there and shake.
so that means what? big bubbles are better? spray etchers are awfully
complicated to build and i have yet to hear of someone building one that
works. Has anyone tried toner transfer with a sprayer? and what about CuCl?
ST