We lay down a photographic mask with the outline of an image which
is then used as a guide for an artist to paint within the lines,
sort of like kids use a coloring book.
The system works well on a silver pendant using Nitric acid, but all
of the acids we’ve used, Hydroflouric, Nitric, HCL, Sulphuric don’t
seem to work well. They are either too aggressive or they don’t etch
when used on a variety of stones.
Is anyone aware of a etch, dye or stain that will give consistent
results when used on stone in the above described process?
what you describe seems like a sandblaster’s job to me. Masking
parts and going over with different abrasives is widely used
standard for glass and stone.
By changing the media, the nozzle size and modifying the air
pressure, one can pretty much influence the results, ie. it is much
more precise than acid etching.
You find more info and a supportive forum for this technique on
as a starting point. Or use “sandcarving” with your favorite search
engine.
etch, dye or stain that will give consistent results when used on
stone
Well, Jon, it’s probably more complicated than you think. I wrote a
while back about plastics, because people tend to say, “It’s
plastic…” I know some also say, “it’s acid…” But which acid
and why? Is the question…
First off, you are probably talking about “rocks”. Rocks are mixtures
of minerals, by definition. Meaning that an acid that etches one of
those minerals may not affect another, or it may. Depends on the
rock.
Generally speaking you could do the job with two acids -
hydrochloric for carbonates and hydrofluoric for silicates. Those
reactions are not interchangeable i.e. HCL won’t touch silicates and
HF won’t touch carbonates, or not much. Nitric might be useful for
some other minerals, and especially copper bearing.
My brother the chemist used to need to dissolve rocks for analysis,
and they used some other things, too, but they are chemist stuff that
you either know or you don’t - it doesn’t bear posting such things
here on Orchid because of the dangers (offlist too…) Basically
you need to match the rocks to the acids - it’s not just a matter of
“It’s acid…” You could etch limestone with HCl all day long…
I evidently missed your first post, but from the answers you are
getting, I might offer something that is different. I can spray pure
metal onto rock (most types), wood, cloth, fiberglass, paper, mache’,
and ? If you were to make sandblasting mask cutouts, I could apply
them to a rock, sand blast a depression and fill the depression with
copper, bronze, ???, even gold or silver if a person had metal to
"spare" (some is burned, some is lost to over- spray and fine
particle “mist”, and I need 20+ feet of 1/16" wire just to get the
"gun" ready to spray. But for copper or bronze, it is terrific, not
too expensive, VERY versatile as to "backup material. If interested,
drop me a line for further I do not have any info about
it on our website as yet, but hopefully soon.
Vio has a good point. Stone is of many different chemical
compositions and you will have to do a lot of experimenting to find
which acid will etch which stone. Then there is the added
complication of veins and impurities of different composition in one
variety of stone.
Do some experimenting with the sandblasting on scraps of the
different types of stone you will be using. For instance, if you used
the same amount of time on a piece of turquois that you used on a
piece of brazilian agate, the turquois stone would probably be half
eroded away.
Do some experimenting with the sandblasting on scraps
I would agree that sandblasting is a possible option - that depends
on the stone being worked on.
I thought I would add that I’ve never strictly “etched” stone, but I
have used acid in masonry work, like to clean bricks and clean
concrete… It takes a LOT of acid to do that…