Hollis on sun 7 sep 08
Dan: I have one regular glaze recipe (a version of Phil Rogers'
standard ash glaze) that calls for Cornwall Stone. The stone I get
from my supplier (Portland Pottery in Braintree MA) arrives in oddly
random-sized clumps in a bag from England, but always integrates well
with the rest of the glaze recipe. I often mix it at the last minute,
because it's one of my most-used glazes. I've never had to mill it or
pulverize it or pre-sieve it. I wonder where you're getting "rocks" and
not ground stone.
Hollis Engley
Hatchville Pottery
E. Falmouth, MA
hatchvillepottery.com
hatchvillepottery.blogspot.com
On Sep 7, 2008, at 10:34 PM, Dan Saultman wrote:
> Cornwall stone is unique, it seems that it can be sold as rocks with a
> small amount of smaller particles.
> How it has passed muster among all of the other glaze compounds that
> must adhere to a particle size etc. is beyond me.
>
> When posed with a last minute glaze mixing need, the Cornwall Stone
> must be ground and pre-seived before adding to the glaze.
>
> Does anyone know who supplies Cornwall Stone already pulverized or
> milled.?
>
> Thanks
>
> Dan
>
Dan Saultman on sun 7 sep 08
Cornwall stone is unique, it seems that it can be sold as rocks with a
small amount of smaller particles.
How it has passed muster among all of the other glaze compounds that
must adhere to a particle size etc. is beyond me.
When posed with a last minute glaze mixing need, the Cornwall Stone
must be ground and pre-seived before adding to the glaze.
Does anyone know who supplies Cornwall Stone already pulverized or
milled.?
Thanks
Dan
Mike on mon 8 sep 08
This is interesting. Do you mean that the 'rocks' are completely
uncrushed raw stones? Or has the powder compressed into hard chunks that
must be broken up again. Can you grab the chunk and break it up by
squeezing and twisting between your hands? I use one type of feldspar
that for some reason always comes like this. I end up having to break up
the chunks before I can sieve. If this is the case, you can use a rigid
round wooden or plastic disc or spatula to run the chunks through a
standard kitchen strainer. This breaks them up enough so that the
smaller pieces just dissolve when water is added and sieving commences.
Until I figured out this method, I was twisting each clump by hand to
break them apart. Worked fine but very tough on the fingers.
Mike
in Taku, Japan
www.karatsupots.com
karatsupots.etsy.com
karatsupots.blogspot.com
blogs.yahoo.co.jp/karatsupots
>
>
>> Cornwall stone is unique, it seems that it can be sold as rocks with a
>> small amount of smaller particles.
>> How it has passed muster among all of the other glaze compounds that
>> must adhere to a particle size etc. is beyond me.
>>
>> When posed with a last minute glaze mixing need, the Cornwall Stone
>> must be ground and pre-seived before adding to the glaze.
>>
>> Does anyone know who supplies Cornwall Stone already pulverized or
>> milled.?
>>
>> Thanks
>>
>> Dan
>>
>
Eva Gallagher on mon 8 sep 08
Our Cornwall Stone also comes lumpy - easy to break when bag is fresh, but
seems to harden with time - maybe something a bit soluable in it? Best way I
found was to mix it up first with a lot of water and use a hand blender to
break up the lumps, then add the rest of the weighed ingredients and all
goes through a sieve nicely.
Eva Gallagher
Deep River, Ontario
http://stephenhilljourneyworkshopjuly2008.blogspot.com/
----- Original Message -----
From: "Mike"
To:
Sent: Monday, September 08, 2008 9:06 AM
Subject: Re: Cornwall Stone - Rocks
> This is interesting. Do you mean that the 'rocks' are completely
> uncrushed raw stones? Or has the powder compressed into hard chunks that
> must be broken up again. Can you grab the chunk and break it up by
> squeezing and twisting between your hands? I use one type of feldspar
> that for some reason always comes like this. I end up having to break up
> the chunks before I can sieve. If this is the case, you can use a rigid
> round wooden or plastic disc or spatula to run the chunks through a
> standard kitchen strainer. This breaks them up enough so that the
> smaller pieces just dissolve when water is added and sieving commences.
> Until I figured out this method, I was twisting each clump by hand to
> break them apart. Worked fine but very tough on the fingers.
>
> Mike
> in Taku, Japan
>
> www.karatsupots.com
> karatsupots.etsy.com
> karatsupots.blogspot.com
> blogs.yahoo.co.jp/karatsupots
>
>
>
>>
>>
>>> Cornwall stone is unique, it seems that it can be sold as rocks with a
>>> small amount of smaller particles.
>>> How it has passed muster among all of the other glaze compounds that
>>> must adhere to a particle size etc. is beyond me.
>>>
>>> When posed with a last minute glaze mixing need, the Cornwall Stone
>>> must be ground and pre-seived before adding to the glaze.
>>>
>>> Does anyone know who supplies Cornwall Stone already pulverized or
>>> milled.?
>>>
>>> Thanks
>>>
>>> Dan
>>>
>>
>
>
Pat Southwood on mon 8 sep 08
Hi Dan and Hollis.
In England we refer to this stuff as Cornish Stone and it always arrives =
slightly bluish in colour with random lumpy bits, some tangerine sized. =
Easily crushed with a rolling pin and straight through a 120 sieve.
Best Wishes,
Pat Southwood
Jon Pacini on mon 8 sep 08
Greetings All --- When we get shipments of Cornwall Stone sometimes it is
still in the wet state ---almost 10% water.
My best guess is they wet grind it and bag it in the woven plastic bags all
in one shot and then ship it as is. No drying time involved.
As it sits around here in the warehouse and dries, it can turn into one big
lump. Many times we must crush it to bag it up into smaller portions. But it
always does seem to break down into powder again.
Best regards,
Jon Pacini
Clay Manager
Laguna Clay Co
Paul Herman on mon 8 sep 08
Hi John,
As I understand it, silica bearing materials are shipped wet in europe
for safety reasons, to guard against inhalation and silicosis. I know
the last time I got a bag of cornish stone from Laguna, it came wet.
Can any of you from over the pond confirm this?
Best wishes,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
On Sep 8, 2008, at 9:49 AM, Jon Pacini wrote:
> Greetings All --- When we get shipments of Cornwall Stone sometimes
> it is
> still in the wet state ---almost 10% water.
>
> My best guess is they wet grind it and bag it in the woven plastic
> bags all
> in one shot and then ship it as is. No drying time involved.
>
> As it sits around here in the warehouse and dries, it can turn into
> one big
> lump. Many times we must crush it to bag it up into smaller
> portions. But it
> always does seem to break down into powder again.
> Best regards,
> Jon Pacini
> Clay Manager
> Laguna Clay Co
jean szostek on tue 9 sep 08
hi paul,
im from belgium, and here we don't do such a thing, but maybe in
great-brittain?
greatings jean
www.szostekjean.be
----- Original Message -----
From: "Paul Herman"
To:
Sent: Monday, September 08, 2008 9:39 PM
Subject: Re: Cornwall Stone - Rocks
> Hi John,
>
> As I understand it, silica bearing materials are shipped wet in europe
> for safety reasons, to guard against inhalation and silicosis. I know
> the last time I got a bag of cornish stone from Laguna, it came wet.
>
> Can any of you from over the pond confirm this?
>
> Best wishes,
>
> Paul Herman
>
> Great Basin Pottery
> Doyle, California US
> www.greatbasinpottery.com/
>
>
>
>
> On Sep 8, 2008, at 9:49 AM, Jon Pacini wrote:
>
>> Greetings All --- When we get shipments of Cornwall Stone sometimes
>> it is
>> still in the wet state ---almost 10% water.
>>
>> My best guess is they wet grind it and bag it in the woven plastic
>> bags all
>> in one shot and then ship it as is. No drying time involved.
>>
>> As it sits around here in the warehouse and dries, it can turn into
>> one big
>> lump. Many times we must crush it to bag it up into smaller
>> portions. But it
>> always does seem to break down into powder again.
>> Best regards,
>> Jon Pacini
>> Clay Manager
>> Laguna Clay Co
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7:01
The Fuzzy Chef on wed 10 sep 08
Hollis wrote:
> Dan: I have one regular glaze recipe (a version of Phil Rogers'
> standard ash glaze) that calls for Cornwall Stone. The stone I get
> from my supplier (Portland Pottery in Braintree MA) arrives in oddly
> random-sized clumps in a bag from England, but always integrates well
> with the rest of the glaze recipe. I often mix it at the last minute,
> because it's one of my most-used glazes. I've never had to mill it or
> pulverize it or pre-sieve it. I wonder where you're getting "rocks" and
> not ground stone.
Yeah. My Cornwall stone often balls up, but the balls are easily crushed
with my large whisk, and dissolve in water in any case.
--Josh
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