H. L. & Joyce Rogers on mon 4 sep 00
Has anyone out there tried using gold raku glazes made with silver
nitrate? If so, what is your opinion on using these glazes? I some
some lovely raku pots at the Southern Highlands Handicrafts Show in
Asheville recently (Stephen Forbes-deSoule). I do a lot of raku,
but have never worked with this chemical. I am getting a little
bored with my glazes and would like to try something a little
different. Also, in looking through my Highwater and Axner's
catalogs, I don't see silver nitrate listed. Does anyone know where
it can be purchased? Does anyone have a recipe for a gold raku glaze
that they have used and liked?
Also, another raku question: I would like to do some brushwork over
my raku glazes, but everything I've tried has changed color or run on
the glazes. I wondered if anyone could tell me what to mix with a
black Mason stain so that I can use it to paint with.
And another question: Has any one used lusters on raku? I have some
Med Mar lusters left over from a project and wondered if they can be
used for raku. Does anyone know? I have not heard of them being
used in this way, and I'm not familiar enough with lusters to really
understand how they work, and whether they would work at all with the
raku process.
Thanks in advance for any info. Clayart is really a Godsend. I felt
for years that I was working in a vacuum, with only a rare chance to
"talk clay" with another potter. I have learned so much from this
group, and not only about clay. Thanks ya'll!!
Joyce R. in N. Georgia
Peg Landham on tue 5 sep 00
Joyce wrote:=20
..."Also, in looking through my Highwater and Axner's
catalogs, I don't see silver nitrate listed. Does anyone know where
it can be purchased? "
Joyce,
I get my silver nitrate from my local pharmacist, who is thrilled to =
order it for my "higher purpose." She thought people only used it to =
burn off warts. At $50 an ounce, it hardly requires a trip to my clay =
supplier. But DO be careful. The stuff is tasteless, odorless and highly =
toxic. When people tell you to use rubber gloves because it stains, =
BELIEVE them! And store it in an airtight, tinted container in a dark =
place. It's very light-sensitive. When you do mix up a glaze batch, mix =
only what you can use immediately. The shelf life is zilch.
Davens in Atlanta now carries Silver Carbonate, which is supposed to be =
much safer to work with, less expensive, and capable of the same =
results. I haven't tried it yet, but plan to when my current supply =
expires.=20
I'm no expert, just a regular raku nut. But if you want to talk more, =
I'm plandham@charter.net
Peg Landham
Birmingham
ILENE MAHLER on tue 5 sep 00
Hi just be careful,wear gloves as silver nitrate stains skin a dark
brown and doesn't come off...Last I heard standart Chemical carries it
I payed $250 a il many years ago...Ilene in finally dry cool Conn.......
"H. L. & Joyce Rogers" wrote:
>
> Has anyone out there tried using gold raku glazes made with silver
> nitrate? If so, what is your opinion on using these glazes? I some
> some lovely raku pots at the Southern Highlands Handicrafts Show in
> Asheville recently (Stephen Forbes-deSoule). I do a lot of raku,
> but have never worked with this chemical. I am getting a little
> bored with my glazes and would like to try something a little
> different. Also, in looking through my Highwater and Axner's
> catalogs, I don't see silver nitrate listed. Does anyone know where
> it can be purchased? Does anyone have a recipe for a gold raku glaze
> that they have used and liked?
>
> Also, another raku question: I would like to do some brushwork over
> my raku glazes, but everything I've tried has changed color or run on
> the glazes. I wondered if anyone could tell me what to mix with a
> black Mason stain so that I can use it to paint with.
>
> And another question: Has any one used lusters on raku? I have some
> Med Mar lusters left over from a project and wondered if they can be
> used for raku. Does anyone know? I have not heard of them being
> used in this way, and I'm not familiar enough with lusters to really
> understand how they work, and whether they would work at all with the
> raku process.
>
> Thanks in advance for any info. Clayart is really a Godsend. I felt
> for years that I was working in a vacuum, with only a rare chance to
> "talk clay" with another potter. I have learned so much from this
> group, and not only about clay. Thanks ya'll!!
>
> Joyce R. in N. Georgia
>
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Bruce Girrell on tue 5 sep 00
Joyce in N. Georgia wrote:
>Has anyone out there tried using gold raku glazes made with silver
>nitrate? If so, what is your opinion on using these glazes?
We have used the gold silver nitrate glaze provided by Gordon Hutchens in
his "Variations on Raku" video. I find the following:
1) It produces a very nice gold - distinctly different that your basic
bright copper - when it works. When it doesn't work, it is a dull mottled
brown or even almost white.
2) To make it work, the glaze must be heavily reduced - in contact with the
organic material even.
3) Note Hutchens' remark to fire in oxidation and reduce in the can. I
suspect that if you fire in reduction, the silver will boil off before you
ever get a chance to get it to the can.
4) The glaze does not need to be thick. The gold appears only as a surface
effect. In fact, you can scrub it off if you get too aggressive trying to
remove some nearby carbon.
5) The glaze is somewhat bubbly and I can't seem to get the bubbles to
break. I suspect that this is from the borax in the recipe, but I don't
really know.
I have some film at the photo shop now and should have it back this
afternoon. I can send a photo of how it turns out if you'd like.
>...in looking through my Highwater and Axner's
>catalogs, I don't see silver nitrate listed. Does anyone know where
>it can be purchased?
Sometimes it's hard to find where they have it listed in the catalogs, but
most companies carry it. Look for the glaze chemicals, "rare chemicals" or
the Lutres section of your catalogs.
The only thing that I don't understand is why it is so expensive. Silver is
just not that expensive and all you need besides that is nitric acid, which
is dirt cheap. Silver is now running about US$5.00/oz or 16 _cents_ per
gram. Throw it in some nitric acid, watch it fizz* and, voila, silver
nitrate. But for some reason, it now costs about almost a dollar per gram.
>Does anyone have a recipe for a gold raku glaze
>that they have used and liked?
The Gordon Hutchens recipe is the only one that I have used, but it works.
It's beautiful when it works well.
>Also, another raku question: I would like to do some brushwork over
>my raku glazes, but everything I've tried has changed color or run on
>the glazes.
Lynne has tried several times to do brushwork on raku pieces with results
similar to yours. One major problem is our good old friend Gerstley Borate.
It bubbles during the firing, which destroys fine lines and distorts the
brush work. You might investigate modifying a majolica base to decrease the
melting temperature. We just haven't had time to do this yet. Our only real
attempt was based on a frit. Despite making a nice white base that didn't
bubble, it had terrible mechanical properties and we abandoned it.
Bruce and Lynne Girrell
in northern Michigan actually getting some pots that we like for a change.
Sometimes those dry spells can be tough. You start asking yourself, "Why did
I choose _this_? Why didn't I just stay with nice predictable colors?"
*DON'T breathe the fumes!!!
Tom Buck on tue 5 sep 00
Bruce:
I sent Ms Rogers a warning re Silver Nitrate being dangerous, and
now you add handling nitric acid too! Ouch. These are nasty chemicals and
need special care, not often seen in a potter's studio.
However, you did jog my memory of an exchange I had with a lowfire
potter in India. We decided that we could use Silver Carbonate in place of
the Nitrate, and the carbonate is tame, compared to the other, a very
strong oxidizing agent.
Now, where do you find silver carbonate? From a laboratory supply
house. Or perhaps Standard Chem in Philly.
Why do they cost so much? Because they are pharmaceutical grade
laboratory chemicals, and the testing to get official approval is what
costs. Plus the fact, that both are sensitive to light, and will
decompose over time even in a dark bown bottle. Last time I checked
neither chemical was available as "commercial" grade, ie, non-lab grade.
And, when I did some gold, I got a good yellowy gold with light to
medium reduction in the bucket; when I dumped a pot on sawdust I got a
dark orangey gold. I did use a different base (Meakin's) and it did bubble
somewhat due (I suspect) to firing too high in the kiln.
So: let's skip the nitric acid routine, OK?
bye for now. peace. tom b.
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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