I.Lewis on sat 18 dec 99
------------------
Be very careful with Silicon carbide shelves in a sodium chloride =
atmosphere.
Any salt which settles, or condenses on the shelf will react strongly =
causing
foaming. This happened to some that I used. I got them because they had been
discarded. Silly people had dropped them. Even though I had a good coating =
of
bat wash, this foaming happened. Eventually you destroy the shelves.
A better way is to build your ware into bungs and separate the pieces with
kaolin alumina wads. Then there is also that trick used by some Salt Glazers=
of
supporting their pots on sea shells. Read any articles you can find by the =
late
Sandra Johnson. She even discarded the notion of having a bricked floor. =
Built
her kiln on the bare earth. Think of the savings. A very innovative lady.
Yes, forget Silicon Carbide shelves unless you want to watch them foam and =
drip.
Ivor. Waiting for information about the salt and ice experiment.
Craig Martell on sun 19 dec 99
Ivor Lewis said:
>Be very careful with Silicon carbide shelves in a sodium chloride atmosphere.
>Any salt which settles, or condenses on the shelf will react strongly causing
>foaming. Eventually you destroy the shelves.
Hi:
This hasn't been my experience with silicon carbs. They work pretty well
and have a much longer lifespan that anything else I've used. I have some
still in use that I bought from another salt potter who used them for years
and they are still very serviceable. Eventually, everything will fail but
I think that silicon carbide shelves will work much better than
others. Haven't tried crystars or advancers yet.
I think that the amount of salt that you introduce into a kiln at each
application can have a bearing on how much slag you build up on the
shelves. The clay is much more reactive than the shelves so the vapor is
going to be attracted to the ware. I usually put in about 2 lbs of salt
per application with about 15 lbs total. This is a 58 cubic foot kiln. I
let the chamber clear pretty well between shots of salt. I get some foamy
salt slag on the shelves but I comes right of with a grinding stone and
doesn't degrade the shelf too much. It's not a lot of slag either. Also,
there are different grades of silicon carbide and some will withstand vapor
glazing better than others.
Sandra's last name was Johnstone and you are right, she was a very
innovative person. An expert in salt glaze and made wonderful pots.
regards, Craig Martell in Oregon
>A better way is to build your ware into bungs and separate the pieces with
>kaolin alumina wads. Then there is also that trick used by some Salt
>Glazers of
>supporting their pots on sea shells. Read any articles you can find by the
>late
>Sandra Johnson. She even discarded the notion of having a bricked floor. Built
>her kiln on the bare earth. Think of the savings. A very innovative lady.
>
>Yes, forget Silicon Carbide shelves unless you want to watch them foam and
>drip.
>
>Ivor. Waiting for information about the salt and ice experiment.
Vince Pitelka on sun 19 dec 99
>Be very careful with Silicon carbide shelves in a sodium chloride atmosphere.
>Any salt which settles, or condenses on the shelf will react strongly causing
>foaming. This happened to some that I used. I got them because they had been
>discarded. Silly people had dropped them. Even though I had a good coating of
>bat wash, this foaming happened. Eventually you destroy the shelves.
We use silicon carbide exclusively in our salt and soda kilns. We get a
very small amount of foamy scale on the bottom side of the shelves, and we
scrape this off after every firing, which is very easy. We use a 50/50
EPK/alumina shelf wash, and that protects the top of the shelf. We have
been using the same silicon carbide shelves in salt for a long time with no
deterioration at all.
Best wishes -
- Vince
Vince Pitelka
Home - vpitelka@DeKalb.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
clennell on mon 20 dec 99
>----------------------------Original message----------------------------
>------------------
>Be very careful with Silicon carbide shelves in a sodium chloride atmosphere.
>Any salt which settles, or condenses on the shelf will react strongly causing
>foaming. This happened to some that I used. I got them because they had been
>discarded. Silly people had dropped them. Even though I had a good coating of
>bat wash, this foaming happened. Eventually you destroy the shelves.
>
Ivor: We got a couple of silicon carbide shelves given to us which we use
in the wood kiln. the friggers sweat this blue foam which lands on the
shoulders of the pots below.. I hate the look of it but have given it a
marketing term in order to sell the pots. I call the blue drips "potters
tears". Hey, it works for me.
Cheers,
tony
Tony and Sheila Clennell
Sour Cherry Pottery
4545 King St.
Beamsville, On. L0R 1B1
http://www.sourcherrypottery.com
e-mail:clennell@bestnet.org
905-563-9382
fax 905-563-9383
Louis H.. Katz on wed 22 dec 99
Ferguson, Ken used to collect these things and glue them to the shoulders of his
pots as he was loading.
Louis
> Ivor: We got a couple of silicon carbide shelves given to us which we use
> in the wood kiln. the friggers sweat this blue foam which lands on the
> shoulders of the pots below.. I hate the look of it but have given it a
> marketing term in order to sell the pots. I call the blue drips "potters
> tears".
| |
|
