Homebrew PCBs

Stefan Trethan wrote:
> 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.

Here you can buy and use toilet un-blocker tablets with several grams of copper.

You can buy and use *sack loads* of copper sulphate lawn moss killer here.

> 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.