HandsInCla@aol.com on fri 4 jun 99
Clayarters,
I recently ordered Silver Nitrate (to use in a Raku glaze) from my ceramic
supplier and was sent Silver Carbonate instead. I thought it was an error
and when I called I was told that Silver Carbonate works exactly the same as
Silver Nitrate. Is this true?
Has anyone ever used the Silver Carbonate in Raku glazes and/or washes to
good effect?
Linda
Tom Buck on sat 5 jun 99
Sure, Linda, Ag2CO3 will work just as well as AgNO3 (nitrate). Handling
it is a bit different though. The nitrate is a strong oxidizing agent, use
rubber gloves, full protection of eyes and skin. Also it is highly soluble
so it goes into the water first, and then the glaze solids, and do not
make the glaze mix thin, keep it close to brushing density (1.65
grams/mL). The AgNO3 will form Ag+ ion when dissolved in water, and it is
the ion that transfers to the pot as adhered material. And when fired and
reduced the Ag+ goes to Ag metal giving the gold sheen.
The carbonate, a yellow powder, is not soluble at all (very
slightly), so it is not as hazardous as the nitrate. You'd likely get best
results by dry blending the powders before adding the water, and screening
the glaze to disperse the solids well. Otherwise you may getting
flecking/spotting of the gold sheen.
The nitrate is generally more freely available than the carbonate
but either will do. And since the Molecular weight of Nitrate is 176 and
the Carbonate is 276, use more carbonate, for every gram of nitrate use
1.6 grams of carbonate, and you'll have the same amount of Silver (as
metal) in the glaze.
Good tests. Tom.
Tom Buck ) tel: 905-389-2339
(westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street,
Hamilton ON L8T 3E1 Canada
Dewitt Gimblet on sun 6 jun 99
Tom, it sounds like Ag2CO3 is easier to work with and more stable in a
glaze mix. Any reason why it not more commonly used?
deg
At 10:13 AM 6/5/99 -0400, you wrote:
>----------------------------Original message----------------------------
>Sure, Linda, Ag2CO3 will work just as well as AgNO3 (nitrate). Handling
>it is a bit different though. The nitrate is a strong oxidizing agent, use
>rubber gloves, full protection of eyes and skin. Also it is highly soluble
>so it goes into the water first, and then the glaze solids, and do not
>make the glaze mix thin, keep it close to brushing density (1.65
>grams/mL). The AgNO3 will form Ag+ ion when dissolved in water, and it is
>the ion that transfers to the pot as adhered material. And when fired and
>reduced the Ag+ goes to Ag metal giving the gold sheen.
> The carbonate, a yellow powder, is not soluble at all (very
>slightly), so it is not as hazardous as the nitrate. You'd likely get best
>results by dry blending the powders before adding the water, and screening
>the glaze to disperse the solids well. Otherwise you may getting
>flecking/spotting of the gold sheen.
> The nitrate is generally more freely available than the carbonate
>but either will do. And since the Molecular weight of Nitrate is 176 and
>the Carbonate is 276, use more carbonate, for every gram of nitrate use
>1.6 grams of carbonate, and you'll have the same amount of Silver (as
>metal) in the glaze.
> Good tests. Tom.
>
>Tom Buck ) tel: 905-389-2339
>(westend Lake Ontario, province of Ontario, Canada).
>mailing address: 373 East 43rd Street,
> Hamilton ON L8T 3E1 Canada
>
Tom Buck on mon 7 jun 99
DEG:
Since both are salts of a precious metal, they are classed as
"laboratory compounds" with very high quality standards. In fact my data
says the Carbonate is used solely as a laboratory material, as is the
Nitrate (0.1 N solution is common in hospital labs). But the nitrate is
also used industrially, eg, photographic materials, so there is a
"commerical grade" made and offered but only on large amounts at a time.
If you or I want 25 grams we'd go to a chemical company willing to sell us
a less than 10 kg amount; we'd get the 25g but we would likely pay $2/g or
$50+ for the small bottle.
When I queried on Clayart in 1997, I was told a San Francisco
supplier would sell 250 gram lots of AgNO3 at a reasonable price, approx
$1/g if I recall correctly. Perhaps those prices still prevail.
The Carbonate, being lab grade, would be found through a Lab
Supply house like Fisher or similar. My guess, and ONLY a guess, is that
the price would be well over $2/g.
So, the nitrate would be much cheaper for those clay people who
can use substantial amounts yearly.
That's how I see it, DEG. Til later. Peace. Tom.
Tom Buck ) tel: 905-389-2339
(westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street,
Hamilton ON L8T 3E1 Canada
On Sun, 6 Jun 1999, Dewitt Gimblet wrote:
> ----------------------------Original message----------------------------
> Tom, it sounds like Ag2CO3 is easier to work with and more stable in a
> glaze mix. Any reason why it not more commonly used?
>
> deg
>
> At 10:13 AM 6/5/99 -0400, you wrote:
> >----------------------------Original
> message---------------------------- >Sure, Linda, Ag2CO3 will work
> just as well as AgNO3 (nitrate). Handling >it is a bit different
> though. The nitrate is a strong oxidizing agent, use >rubber gloves,
> full protection of eyes and skin. Also it is highly soluble >so it
> goes into the water first, and then the glaze solids, and do not >make
> the glaze mix thin, keep it close to brushing density (1.65
> >grams/mL). The AgNO3 will form Ag+ ion when dissolved in water, and
> it is >the ion that transfers to the pot as adhered material. And when
> fired and >reduced the Ag+ goes to Ag metal giving the gold sheen. >
> The carbonate, a yellow powder, is not soluble at all (very
> >slightly), so it is not as hazardous as the nitrate. You'd likely get
> best >results by dry blending the powders before adding the water, and
> screening >the glaze to disperse the solids well. Otherwise you may
> getting >flecking/spotting of the gold sheen. > The nitrate is
> generally more freely available than the carbonate >but either will
> do. And since the Molecular weight of Nitrate is 170 (1 atom Ag)
and the Carbonate is 276 (2 atoms Ag), use less carbonate, for every
gram of nitrate, use 0.8 grams of carbonate, and you'll have the same
amount of Silver (as metal) in the glaze.
> > Good tests. Tom.
> >
> >Tom Buck ) tel: 905-389-2339
> >(westend Lake Ontario, province of Ontario, Canada).
> >mailing address: 373 East 43rd Street,
> > Hamilton ON L8T 3E1 Canada
> >
>
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