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Glass Etchant


#1
 Frosting stones From: "Suzanne Wade" <suzanne@rswade.net> I've
used this type of etching cream for doing a gentle etch on glass
baby food jars as part of a craft project. The kind I bought is
brand name "Armor Etch." According to my science teacher dad, its a
type of fluoric acid (NOT hydrofluoric), which is much milder. I
didn't find it to be particularly nasty, although I'm still careful
to use gloves, safety glasses, and good ventilation. I figure it
doesn't pay to take unnecessary chances, and it only takes one
accident to discover *why* safety precautions are a good idea. :-)
The Armor Etch produces a gentle, matte surface on clear glass, not
a really a strong, white frosted look. I experimented with leaving
it on longer, but didn't find it deepened the finish overmuch. I
haven't tried it on anything but glass.

Hi Suzanne, I am a chemist by trade, and wanted to comment on the
thread above - the most common glass etchant which is
non-hydrofluoric acid is ammonium bifluoride. This material can be
purchased in a granular or crystaline form, and is dissolved in water
to make an etching solution for glass and certain other silicates.
Note that it also has the same exposure limit as HF acid, so don’t
breathe the dust at all! I also find that adding a wetting agent
increases the activity radically, not to mention temperature. If you
add the anionic surfactant sodium lauryl sulfate, and heat the
solution to about 110 degrees F, you will have a fairly active
solution suitable for many applications. Getting SLS to dissolve in
this solution from powder form is difficult, so you can simply add a
few teaspoons to 5 gallons of something common that contains sodium
lauryl sulfate as its main ingrediant (listed first on label) like
hair shampoo and that will work fine.

You can experiment with the concentration of AB, and see what you
like best. I use about 5 pounds to 20 gallons of water with about
500 grams of sodium lauryl sulfate powder heated to 110F for
reference. It is much safer to handle than hydrofluoric acid,
although the exposure limit is the same. In other words, you don’t
have to worry much if you splash some on your skin for example - just
wash it off. Splashed HF acid on your skin is another matter
entirely!

Paul Ahlstedt