On Sun, 20 Jul 2008 09:39:56 -0700, in rec.crafts.jewelry helen
wrote:


Hey Doc,

What's "safety alcohol"? I've got denatured alcohol just like you
said (we call it methylated spirits). Over here, they add a purple
dye to it but other than that, it's the same denatured alcohol as you
use.

There may actually be differences. Denatured alcohol or methylated spirits are
both initially ethanol. Same stuff as in alcoholic drinks. In order to make
the stuff undrinkable, done usually to avoid the taxes imposed on alcoholic
beverages, several types of agents can be added to make the stuff toxic.
Methanol (wood alcohol) is one of the most common of these. But the amount
added, or even if that's what's added, is not standardized by any means, either
by country, or even within the U.S. In the U.S., Different brands may use
different means or amounts of methanol to denature the stuff, and some brands
may also have small amounts of water in the mix too. Both water and methanol
are able to dissolve more boric acid than does ethanol itself. so a brand of
denatured alcohol with more methanol, or a tad of water, might end up with a
significantly different performance when mixed with boric acid as a fire coat.

Even straight ethanol does dissolve a little boric acid, so then the question is
whether there's enough boric acid deposited by a dip in the simple liquid,
without stirring, for the intended use. Some of that, too, will be a matter of
preference, and what you're doing. If you're only protecting gold from
oxidation, the need is somewhat less stringent than if you're soldering new
prongs on a diamond, which needs good protection from the air or it will be
damaged.

As I said at one point earlier on, I prefer to stir the boric/alcohol mix,
simply because that way I KNOW I've got enough on it, no matter what I'm doing.
Habit. In many cases, it may be more than needed, but that causes no harm. If
Doc finds it adequate to just dip without stirring, it might be the same mix, or
it might be a little different than mine, or it might just be that for what he's
doing, it's working fine. Who knows. Everyone has slight differences in the
way they do the same tasks. We'll go nuts if we try to figure out each and
every minor detail when it offers no real advantage one way or the other. If it
works, go with it. If not, modify the procedure...

cheers

Peter