I wonder why more people aren't using it then. It is also mentioned here:
"SUPER CHARGING Ferric Chloride"
A new additive to help this etchant be more effective!
http://www.pcbfx.com/main_site/pages/tech_support/no_etching_tank.htmland at the link they refer to, I came up with the following info for making it:
http://www.polymetaal.nl/beguin/mape/edinburgh_etch.htmEdinburgh etch mix ratio for copper etching:
1 liter saturated ferric chloride solution
200ml hot tap water
67 grams citric acid powder
or
32 fluid ounces saturated ferric chloride solution
6.75 fluid ounces hot water
2.36 ounces citric acid powder
Citric acid powder is typically available in 3 oz. bottles at beer brewing/wine making supply stores in the US.
"Gradually add the citric acid powder to the hot water while stirring continually. Once this has fully dissolved, gradually pour this into the ferric solution and keep stirring until you have produced a uniform liquid.
"Good results are ensured at 18 to 20°C, but higher temperatures of up to 30°C can further improve biting times as well as the overall responsiveness of the mordant (aka etchant). This mordant is exceptionally long lasting; a tank filling used daily at the EPW, occasionally topped up to compensate for evaporation loss, has been known to remain active for up to one year without a significant drop in its biting properties. When eventually the mordant acquires a deep olive colour it becomes less active and is then ready for replacement and disposal.
--- In Homebrew_PCBs@yahoogroups.com, Malcolm Parker-Lisberg <mparkerlisberg@...> wrote:
>
> I use Edinburgh etch in my heated bubble tank, <http://www.megauk.com/pcb_processing_tanks.php> they doa hobby version too, < http://www.megauk.com/hobby_equipment.php>
>
> The etch seems tospeed up the more you use it and the older it gets.
> I was given the tank with its faulty control system (it had been etched as well). I built a newone in an IP67 box with electronic temp control.
>
> Malcolm
> Â
> I don't suffer from insanity I enjoy it!
> Mene, mene, tekel, upharsin
> The writing is on the wall.
>
>
> ________________________________
> From: sheldon_mp_cooper <bigbazinga@...>
> To: Homebrew_PCBs@yahoogroups.com
> Sent: Tuesday, March 20, 2012 7:02 PM
> Subject: [Homebrew_PCBs] Re: Rejuvenating ferric chloride etchants (was: Darkening laser printer toner?)
>
>
> Â
> Here's a guy whose rejuvenation chemistry has allowed him to use the same ferric chloride etchant for four years (watch that chlorine gas, though):
>
> http://www.qsl.net/iz7ath/web/02_brew/14_howto/02_clor/index.htm
>
> BTW, has anyone ever tried this (add citric acid to etchant)?:
>
> FERRIC CHLORIDE AND THE EDINBURGH ETCH
>
> http://www.lawrence.co.uk/acatalog/etch.pdf
>
>
>
>
> [Non-text portions of this message have been removed]
>