On 06/14/2010 12:09 PM, James wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, "Dale J. Chatham"<dale@...> wrote:
>
>> In my opinion:
>>
>> H2O2 doesn't stay H2O2 for long. It is likely mostly H2O by the time it
>> reaches the sewer plant.
>>
>> HCl? As you say, not a huge problem, it tends to lower pH, which may be
>> precisely what the sewer plant wants and I'd not be surprised if they
>> didn't use the stuff themselves.
>>
>> The worst thing in the effluent from etching may well be CuCl, which is
>> pretty toxic to crustacea, snails and perhaps (guessing) bacteria, which
>> is why some folks neutralize it with NsOH (Drano) before dumping it.
>>
>> Of all the things you could poor down your drain, HCl is likely the most
>> innocuous.
>>
>>
>>
>>
>
> It will corrode the crap out of ∗any∗ metal fittings, even stainless. Trust me on that one, I rinsed off a PCB in the sink and the tiny amount that dripped off the board left rust spots on the drain surround. I now mix up a pitcher of water with some baking soda in it and use that to rinse things off.
>
> Anything with dissolved copper should not be dumped down the drain, at least if you live in a coastal area like I do where the water eventually ends up in the ocean.
>
Well, I thought we were talking about environmental impact. I stand by
my statement that HCl is probably the most innocuous thing you can dump
down the sink, in that regard. It's difficult to make myself remember
that folks have metal pipes for drainage :) Even when my goosenecks
were metal, I'd replace them with PVC just 'cause.
>
>
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