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Subject: Re: [Homebrew_PCBs] Blackening Copper

From: Stefan Trethan <stefan_trethan@...>
Date: 2004-05-13

On Thu, 13 May 2004 07:24:08 -0700, Mark <mfraser@...> wrote:

> Gun Blueing from your local hardware store.
> Very slightly dampen a corner of a cloth with it, rub briskly.
> You'll get a black sooty deposit if you put too much on / leave
> it wet etc.; start with a less dampened corner of the cloth.
> Keep rubbing....
>
> Same deal as prep for etching / plating - clean. Kitchen cleanser
> like ajax etc. Wash well.
>
> Rubber gloves - it leaves a nasty odor that's hard to wash off.
> Nothing terrible in the MSDS.
>
> CHeaper than most of the brass-blackening compounds in the few
> hobby shops that sell them. Faster, too.
> /mark
>
>

Never seen anywhere around, thought about it too...

I am on to something, left it immersed in strong NaOH solution mixed with
sulphur overnight.
It got black, very black, but the copper was etched :-( . Might work just
fine if
i only leave it for a short time.

ST