Luxi-Flux is methanol and boric acid and methylene blue dye. The
reason it works so well is that boric acid is readily soluble in
methanol and so it caries lots of boric acid onto the work. The
typical jewelers fire coat of boric acid and denatured alcohol
(ethanol) does not work nearly as well because boric acid is not very
soluble in denatured alcohol so you don’t transfer as much of it to
the work. But methanol is very toxic, both fumes and skin contact are
hazardous. Liver and kidney failure and blindness are possibilities
from too much exposure to methanol. So if you are going to use it
make sure you have very good ventilation and don’t get it on your
skin
One more thing, my comments were not to suggest not using methanol
based firecoat. I use a similar a product without the dye. Just be
aware what it is and what the dangers / precautions are.
Was interested to read about the Luxi Flux contents from James
Binnion. I had put about a cupful in a clean olive jar with the big
opening so I could dip items in it. After leaving it closed with the
metal lid for a few weeks in my basement studio, (haven’t created
anything lately down there), noticed the other day that the metal lid
had become encrusted with a white powder and all down the sides of
the jar. The jar had been sitting close to the metal/(old
crockpot)water pot, where I rinse everything before pickling, and the
pot had a big white blotch on it as if it had been sprayed out of the
jar! What an eye opener, and what the heck was happening? What kind
of expansion was going on in the tightly closed jar - amazing!
Fortunately I have done all my soldering (with Prips or Batterns),
clean up, design and teaching in my new garage turned studio! What
can be the disposal situation of such caustic liquid? After reading
James’ e-mail I will handle with gloves - but how to neutralize the
stuff?
After leaving it closed with the metal lid for a few weeks in my
basement studio, (haven't created anything lately down there),
noticed the other day that the metal lid had become encrusted with a
white powder and all down the sides of the jar. The jar had been
sitting close to the metal/(old crockpot)water pot, where I rinse
everything before pickling, and the pot had a big white blotch on it
as if it had been sprayed out of the jar! What an eye opener, and
what the heck was happening? What kind of expansion was going on in
the tightly closed jar - amazing! Fortunately I have done all my
soldering (with Prips or Batterns), clean up, design and teaching
in my new garage turned studio! What can be the disposal situation
of such caustic liquid? After reading James' e-mail I will handle
with gloves - but how to neutralize the stuff?
It is not that it is all that caustic. Methanol is mildly corrosive
but that is not what you are seeing It is very difficult to keep the
vapors contained. Many normal sealing gaskets are fairly permeable to
the methanol. Unless your jar had a butyl rubber or similar type of
low permeability seal the methanol just passed right through it. The
boric acid is carried in the vapors of the methanol. The white stuff
you see is the boric acid deposited on surfaces as the methanol
vapors sublime away. This is why the mixture is used as a gas flux
agent in water torches and in industrial brazing torch systems. To
get rid of that small amount you have just place the open jar
outside for a day or so and it will evaporate to speed the
evaporation place it in a flat container like a pie tin. Then all
that will be left is the boric acid.