Pat Southwood on sun 5 sep 04
Hi List,
Just got back from the Canaries and confess to bringing home a little =
bit of black volcanic sand.=20
I dont want to waste what I've got.
Any hints of of it's properties from anyone?
I am assuming that I will replace it for flint in any given recipe and =
see what happens.
Does reduction make any difference?
Not trying to be lazy, just havn't got much in the way of supplies to =
experiment with.
Presuming it's not just Iron Oxide mixed with silica though?
Is it fresh (ish) igneous rock?
Yours,
Pat Southwood.
pat@southwwod4.fsnet.co.uk.
Ron Collins on sun 5 sep 04
I use black volcanic beach sand a lot. I make lots of colored porcelain
jewelry and either you can add it to porcelain, or sprinkle it on top and
smooth in. It will melt at cone 5/6 and you will enjoy playing around with
it........you can wash it also, if you are picky and put it out on newspaper
to dry. It makes a great speckly body, but if you don't have much, mix it
in slip and apply on top..........just have fun...has lots of manganese,
etc, and will lower the melting temp if used enough......I use the very fine
volcanic black pumice, and also the more coarse beach sand, but mostly the
fine 100 mesh pumice......I tried, in a recent workshop I gave, to use
ilimite as a subsitute for the ones in the class who live in the north
americas for the fine volcanic pumice and it's not as pretty as the
propected stuff.........Melinda Collins, Antigua, Guatemala
Bonnie Staffel on mon 6 sep 04
Dear Pat,
You have touched on a subject dear to my heart. You can do a test on the
sand with a magnet to see if it is attracted. If so, then you have a high
iron bearing material. On the beaches of Lake Michigan, the wind sometimes
blows the white sand away from layers of black sand. I was so interested in
introducing iron spots in my clay, that I got a 5 gallon glass jar and
filled it. My husband insisted that if I wanted it, I would have to carry
it. Geez. Even had to climb up steps to the top of the dune. My will to
keep it survived and I put it in my clay to create the iron spots. I had an
Alpine gas kiln at the time. However, I found that the glazes with this
sand enriched body shivered on the rims. No Clayart then to ask questions
of. So in researching all the books and articles I could find, did deduce I
had too much iron for the temperature. I could either reduce the temp. or
remove some of the iron. I reduced the temperature and then my pots
survived. This was fifty years ago, imagine.
When I was at Cranbrook, one of the very first pots that Toshiko gave to me
was a heavily iron spotted bowl. She brought some of the Hawaiian volcanic
sand with her. Hers looked more like manganese spots since I also tested
granular manganese in a few of my pots. Possibly it was a mixture of
manganese and iron.
At any rate, I did not adjust any of the materials in my clay. I did want
the iron spotting which was part of my love affair with reduction glazes.
When I had to change to oxidation firing, I still searched for glazes that
had a reduction look. I have finally accepted the electric kiln for what it
does and gives.
By the way, Mel, the green glaze on one of your pots reminded me of Carlton
Ball's colored glaze recipes he offered in CM many years ago. He was one of
the early potters who also, I believe, loved color outside of Potters'
Brown. At least his were my first encounter with published colored glazes.
I just heard from VaseFinder Charlie Blim, that he saw a picture of a bowl I
made in the 1964-65 Syracuse National Exhibition on the cover of the
catalog. That series of pots was from Ball's recipes.
I experimented with oil spot glazes back then as well. I think it would be
fun to get out that old recipe and try it again. I heard a rumor that
Browns are making a comeback in sales to collectors.
Warm regards,
Bonnie Staffel
http://webpages.charter.net/bstaffel
http://www.vasefinder.com/
Potters Council member
Ivor and Olive Lewis on mon 6 sep 04
Dear Pat Southwood,
This may be finely ground Obsidian, a volcanic glass. So it could act
a bit like a frit
Best regards.
Ivor Lewis.
Redhill,
S. Australia.
steve harrison on mon 6 sep 04
Hi Pat,
Your sand sounds like it is probably a mixture of ilmenite, with rutile
and possibly some zircon. i doubt if there is much silica(quartz, or
flint) in it. Silica is almost never black, only as obsidian which is
pretty rare.
I'd try it as a glaze colourant and crystal former. You'll probably get
a mat spangley brown. Try adding it as a line blend between 3% and 15%.
but if you only have such a small amount and don't want to try testing.
Go for broke and add the full 10% into your favourite glaze and take
the consequences.
You will need to grind it up fine, it will be quite hard in a mortar
and pestle, do you have access to a ball mill?
Best wishes
Steve Harrison
Hot & Sticky Pty Ltd
5 Railway Pde
Balmoral Village
NSW 2571
Australia
http://ian.currie.to/sh/Steve_Harrisons_books.html
On Monday, September 6, 2004, at 05:59 AM, Pat Southwood wrote:
> Hi List,
> Just got back from the Canaries and confess to bringing home a little
> bit of black volcanic sand.
> I dont want to waste what I've got.
> Any hints of of it's properties from anyone?
> I am assuming that I will replace it for flint in any given recipe and
> see what happens.
> Does reduction make any difference?
> Not trying to be lazy, just havn't got much in the way of supplies to
> experiment with.
> Presuming it's not just Iron Oxide mixed with silica though?
> Is it fresh (ish) igneous rock?
> Yours,
> Pat Southwood.
> pat@southwwod4.fsnet.co.uk.
>
> _______________________________________________________________________
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>
>
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