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Etching Obsidian?


#1

Greetings, Here’s an obscure notion: Is it possible to etch obsidian
using the same techniques and materials employed in ordinary glass
etching?; and now that I think of it, how about carbonates like
malachite, and rhodocrosite; can they be etched in a controled manner
using HCl? If anyone has tried, toyed with, or mulled over the above,
I would appreciate hearing from them. Much Obliged, Ethan


#2

from a materials point of view - absolutely should be possible. You
may need to experiment, especially with masking materials on natural
materials (which can be porous and hence retain some material in
unexpected ways…)


#3
can they be etched in a controlled manner using HCl?

Hi Ethan, I thought tht Hydrofluoric acid was used for glass
etching, and I would not touch it with a barge pole! I work with
viterous enamel and there’s a matting salt which is a hydrofluoric
salt (sorry, don’t know the chemical ID) I believe it is less
dangerous.

This is quite slow but does work. To remove enamel I soak the piece
for a few days, every day rinsing, scratch brushing, r& dry before
replacing in the solution.

Goggles, gloves, apron and the usual safety gear.

Interesting question though!

Tamizan


#4

By mistake I found that you can easily etch carbonates with ordinary
pickle. malachite never looks the same…

Judy Hoch


#5

Ethan- Were it my project I would sand blast it.

I used to work in glass back in the stone age when we used powerful
acids to etch designs into flashed glass. Etching through one layer
of color to reveal another with a design.

Then we switched to bead or sand blasting. So much safer and so much
easier to control. You can use different grades of blasting media to
get get either a very fine finish or a coarse one.

Have fun and make lots of jewelry.

Jo Haemer
timothywgreen.com


#6

We used to use hydroflouric acid to remove porcelain from crowns (if
we had to remake them) leaving the metal coping. Dangerous stuff.
Really.


#7
By mistake I found that you can easily etch carbonates with
ordinary pickle. malachite never looks the same...

By golly - that sounds a lot of fun, with any number of exciting
possibilities…! What would one use as a resist, I wonder? Nail
polish? Asphaltum? PnP?

Janet


#8
By mistake I found that you can easily etch carbonates with
ordinary pickle. malachite never looks the same... 
By golly - that sounds a lot of fun, with any number of exciting
possibilities.. 

One of the mistakes made now and then by many beginning (and
sometimes not so beginning) jewelers is accidentally putting a piece
in the pickle that has malechite, pearl, lapis, rhodachrosite,
peridot, or a number of other sensative gems in it. In the case of
some of these, like pearl or malechite, you will find almost
immediately that you’ve not had fun, and now either need to repolish
or replace the sometimes now missing gem. It’s a lesson most such
jewelers won’t have to repeat all that many times before it sinks
in…

Peter


#9

straight or dilute HF is silly dangerous - not the most dangerous
substance known to man, by a long shot

but stupid enough…

having said that, there are plenty of products based on HF that are
less dangerous if treated right - they usually consist of a buffered
solution, so that only a little bit of HF is active at a time.

On the other hand if you have access to a sand blaster that may be
all you need.


#10

back when I did metallugry, etching polished samples to see the
microstructure was part of the curriculum. IIRC, there was a bottle
labelled Ficks Reagent for exposing prior austenite grain boundaries
by selective etching of Phosphates… That was in reality a HF
solution @ ~1%…

the things you don’t know…