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Subject: Re: Copper plating material(s) for a neophyte - tinning brush

From: "Dave" <wa4qal@...>
Date: 2006-01-11

--- In Homebrew_PCBs@yahoogroups.com, "Blair, William"
<William_Blair@b...> wrote:
>
> Steve Greenfield wrote:
>
> > "Stefan Trethan" wrote:
> > > ... simply mix solid chunks of colophony resin with
> > > methylated spirits (ethanol alcohol) ...
> >
> > For those of us in the US, I believe you mean what would
> > be called "denatured alcohol" here. It is primarily ethanol
> > (grain alcohol, therefore drinkable by itself) mixed with
> > methanol to make it toxic.
>
> I haven't seen any (genuine) "denatured alcohol" that made use of
> methanol in a long, long time ... simply because the mixture _IS_
> toxic. What gets used now is denatonium benzoate, the same stuff
> used in anti-nail biting polish for kids. While it's not toxic, I
> understand no human can stand its taste, and if any actually gets
> ingested, nausea results. It also includes methyl isobutyl ketone
> and acetone (dimethyl ketone), which are also toxic but not brain
> damaging like methanol.

There are quite a few materials authorized for denaturing ethyl
alcohol. The exact formulas may be found in the US government
regulations 27 CFR Part 21:

http://www.access.gpo.gov/nara/cfr/waisidx_05/27cfr21_05.html

> In the U.K., however, denatured alcohol formulations do include
> methanol (and a few other nasty things if I remember correctly).
>
> Isopropyl alcohol is quite a different thing, but which is most
> usually found on drugstore shelves labeled as "rubbing alcohol"
> or just "alcohol." It doesn't need to be denatured since nobody
> wants to drink it in the first place.
>
> I don't know if any of this makes any difference but it wouldn't
> be the first time if it did. I assume colophony resin dissolves
> in any sort of alcohol, regardless of the presence or absence of
> methanol. But, if colophony resin _won't_ dissolve in isopropyl
> alcohol, then an effort will be needed to find genuine denatured
> ethanol. And, if that's hard to find (as it is here), then I say
> just use Vodka (unless, for some odd reason, the colophony resin
> actually does require at least a little bit of methanol, say 10%
> or so).
>
> --
> WB

Dave