I've been using the same Ferric Chloride for years and years... I use a
vertical tank (TupperWare Cereal container). Anyone wants a photo of it
let me know.
Drill two holes in the board and thread some 24AWG plastic coated wire
through the holes, then suspend it in the tank. I usually end up
agitating the board by lifting it out of and dropping it back in the FC.
There is still a tendency to etch faster at the top of the board, but
the difference is only about 2 minutes.
Etching time is still 10-12 minutes and has not changed since I
purchased the stuff at rat shack some years ago... 1995 I think it
was... I still have the original bottles somewhere...
The level is going down and last tiem I ecthed a 5" X 6" board I needed
to add some FC, as I did not have any, I simply added 1/2 pint of
water....
There is a crusty ring around the top of the FC and sometimes a coating
develops on the surface ( temperature dependent I think) anyway that
goes away by simply heating the entire Tupperware container in a hot
water bath and stirring for 1-2 minutes.
IMHO people that keep using new mixture of FC are wasting time and
money.
Just how I do things.
COS (change of subject) for those interested I posted a photo of how I
rivet Harwin via pins
http://hans-w.com/pcb_harwin_rivets.jpgThe four pads at the lower right are half of an SO8, should help to
gauge size.
Hans Wedemeyer
Steve Greenfield wrote:
>
> Yep, biggest problem I've had with etching in a flat pan is that no
> matter what you use or how hot you get it, etched copper and used
> acid builds up in a layer and slows the etching process. Minor
> swishing back and forth just means that the edges etch but not the
> center.
>
> So no matter what I use, I want to use a vertical tank, probably
> with a bubbler to keep it moving.
>
> Steve Greenfield
>
> PS I love this list!
>
>
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