Just an idea for pumping etchant...
What about a peristaltic pump?
The ones I have seen use a silicon rubber tubing and good for all sorts
of fluids.
Simon Whitehead
On Tuesday, Apr 22, 2003, at 10:45 Europe/London, Leon Heller wrote:
>
> ----- 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
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Simon Whitehead
4 Colleton Crescent
Exeter
Devon EX2 4DG
England
01392 217873
s.whitehead@...