Acid Etching

How do you acid etch silver? What set up do you need? I can't seem to find
anything about it on the net, am I searching for the right thing?

Heres an example: http://www.catherineondrey.com/egyptiansun.html I've got
some really cool patterns in my head, but haven't got a clue about how to
start making them real! Would a rolling mill (is that the right name for
it?) Do the same thing?

Charlie.

On Fri, 17 Dec 2004 09:40:08 GMT, "Charlie"
wrote:

How do you acid etch silver? What set up do you need? I can't seem to find
anything about it on the net, am I searching for the right thing?

Heres an example: http://www.catherineondrey.com/egyptiansun.html I've got
some really cool patterns in my head, but haven't got a clue about how to
start making them real! Would a rolling mill (is that the right name for
it?) Do the same thing?

Charlie.

Go to your local Radio Shack and pick up a kit for etching printed
circuit boards. Read the instructions and adapt them to etching
silver.

It's actually a simple process conceptually, although the details can
be tricky and are best learned by experience.

The reason for using the Radio Shack kit is that it includes the
ferric chloride etchant. That's not as dangerous as etching with acid
and gives good results on silver, steel, etc.

--RC
Projects expand to fill the clamps available -- plus 20 percent

On Fri, 17 Dec 2004 07:48:36 -0800, in ?? wrote:

On Fri, 17 Dec 2004 09:40:08 GMT, "Charlie"
wrote:

How do you acid etch silver? What set up do you need? I can't seem to find
anything about it on the net, am I searching for the right thing?


Go to your local Radio Shack and pick up a kit for etching printed
circuit boards. Read the instructions and adapt them to etching
silver.

It's actually a simple process conceptually, although the details can
be tricky and are best learned by experience.

The reason for using the Radio Shack kit is that it includes the
ferric chloride etchant. That's not as dangerous as etching with acid
and gives good results on silver, steel, etc.


I beg to differ, a bit. the kit from radio shack contains ferric chloride etchant, as
noted. that works well on copper, brass, bronze, etc, but it will NOT work well on
silver. Ferric chloride is a salt of hydrochloric acid, and works the same way, but a
bit more evenly and slowly as an etchant. HCl forms, with copper alloys, copper
chlorides, which are water soluable. But with silver, the silver chloride produced is
not water soluable, so immersion in that acid or an HCL acid salt produces a quick
reaction that forms a whitish silver chloride film on the surface, but then the reaction
stops there, as the initial film of silver chloride blocks further access to the metal.
So no real etching takes place.

What you need is either the acid, or a salt thereof, of nitric acid. Normally, a 10
percent solution of concentrated nitric in water is used, resulting in a fairly dilute
acid bath. One can go more dilute if desired, but it gets slower. This dilution is,
while still needing some decent care (as with any acid, including the ferric chloride
etchant) and ventilation, a lot safer than the concentrated nitric acid. Alternatively,
one can use a solution of ferric nitrate salt in water, which works even more evenly
than the raw acid, and doesn't evolve quite as much fumes as the acid itself.

Either way, one can speed up the etching process by use of a low voltage electric
currant, hooking up the piece to be etched as the anode, with 2 to 4 volts DC. A simple
battery works fine for this. The electro etch isn't needed, but does speed things up.
Use a piece of graphite for the cathode.

Also of benefit is to use a small aquarium air pump to run a bubble line into the acid,
so the liquid is agitated and stirred.

A large amount of acid is not needed, and the used acid bath from silver etching can be
saved and used again until it's completely saturated and depleted. In fact, a somewhat
used bath will often produce a cleaner etch than brand new more agressive acid.

The resists used to define the design can range from hand painted on asphaltum varnish
(check with an arts supply house that carries printmaking supplies and graphic arts
supplies, as might be used in art school print making classes), which can be simply
scratched through to define areas to be etched, to iron on sheets where the design if
put on the sheet with a photo copier or laser printer (the brand is called PNP blue.
Get it from Reactive Metals Inc, among other places), or to more formal photo resist
processes well suited to higher volume production. Those are liquids used to coat the
metal, which are photo sensative. Exposed through a negative and then developed like
film, unexposed areas wash off leaving the photo design as your etch resist. Kodak KPR
is one such material, there are others.

Hope this helps.

Peter Rowe

Charlie wrote:
How do you acid etch silver? What set up do you need? I can't seem to find
anything about it on the net, am I searching for the right thing?

Heres an example: http://www.catherineondrey.com/egyptiansun.html I've got
some really cool patterns in my head, but haven't got a clue about how to
start making them real! Would a rolling mill (is that the right name for
it?) Do the same thing?


In addition to what others have mentioned, an alternative to etching is
reverse electroplating, where you mask the pattern and electroplate away
the areas to be recessed -- and don't worry about the surface you plate
onto. This can help you avoid use of acid, but.... depending on what you
use as an electrolyte.... Reverse electroplating has the capability for
avoiding undercutting and other problems you can have when acid etching.

As far as a rolling mill goes, they're expensive, you still need a
pattern source, etc. And unless you have other basic uses for the
rolling mill, probably not worth it for you.

Thanks for the advice guys. I guess that having an interest in physics will
help here, (I'll dig out my old textbooks!). The only problem is, the
sources you've mentioned are in the US and I'm not. Anyone know about
places in the UK I could get this stuff? I have a radio shack here but they
only sell components really, although I shall wander down and ask them!

Charlie.

"C. Gates" wrote in message
...


Charlie wrote:
How do you acid etch silver? What set up do you need? I can't seem to
find
anything about it on the net, am I searching for the right thing?

Heres an example: http://www.catherineondrey.com/egyptiansun.html I've
got
some really cool patterns in my head, but haven't got a clue about how
to
start making them real! Would a rolling mill (is that the right name
for
it?) Do the same thing?


In addition to what others have mentioned, an alternative to etching is
reverse electroplating, where you mask the pattern and electroplate away
the areas to be recessed -- and don't worry about the surface you plate
onto. This can help you avoid use of acid, but.... depending on what you
use as an electrolyte.... Reverse electroplating has the capability for
avoiding undercutting and other problems you can have when acid etching.

As far as a rolling mill goes, they're expensive, you still need a
pattern source, etc. And unless you have other basic uses for the
rolling mill, probably not worth it for you.