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Subject: Re: [Homebrew_PCBs] Re: Getting ready to switch from Ferric Chloride to ???????

From: "Stefan Trethan" <stefan_trethan@...>
Date: 2008-10-07

The limit here in Europe is 0.5mg copper per liter of sewage. Some time ago
i calculated how much water you'd need to dilute the copper form a single
board enough and it was something like several cubic meters (one cubic meter
= 1000l = 1ton). Now you probably don't want to flush that much down the
drain every time, so it is illegal.

However, averaged over time and a larger area you probably reach that level
of dilution easily. That doesn't make it legal though.

Personally, i use CuCl and if it ever grows to more than i need i will
decide what to do with the excess. So far that has not happened. I wash the
boards in the sink, having decided that the rinsing water does not contain
enough copper to pose a problem.

You can buy small commercial stations now that use ion exchangers for
treatment of rinsing water.

ST


On Tue, Oct 7, 2008 at 11:10 AM, Leon <leon355@...> wrote:

>
> The occasional pint or two won't matter. Ferric chloride is used for water
> treatment, and the amount of copper is negligible, compared to what must
> get
> into the water from the copper pipes used in plumbing.
>
> Leon
>
>


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