Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

----- Original Message -----
From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, April 22, 2003 9:59 AM
Subject: Re: [Homebrew_PCBs] Re: Cu + HCl -> CuCl2 : part 3


> I'm wondering if anyone has thought about spray etching...
>
> this may give uniform etch, may be very fast and may also regenerate the
etchant.
> but i have no idea if you can prevent a cheap pump from being eaten away
soon.
> the plastic pumps i know have a permanent magnet exposed to the fluid as
rotor. and i believe nylon
> bearing.
> but this may also be too complicated and even dangerous (etchant jet...)..
>

I think that spray etching is used by most of the PCB manufacturers.

I've often wondered whether ultrasonics would be useful. We used ultrasonic
cleaning where I worked many years ago with very high-power units. The
cavitation produced on the surface of the copper should give very rapid
removal. The effect of the etchant on the transducers needs to be solved, of
course, perhaps by coupling them to the base of the tank, so they aren't
exposed.

Leon
--
Leon Heller, G1HSM
leon_heller@...
http://www.geocities.com/leon_heller