John Britt on tue 28 dec 10
I have heard that Cornwall Stone is no longer available and wanted to see=
=3D
if=3D20
anyone else has heard that? Highwater Clay only sells 10 lbs at a time n=
=3D
ow.
John Britt
www.johnbrittpottery.com
DJBrewer88 on wed 29 dec 10
Wow! I've got two 5 gallon buckets of Cornwall Stone from a potter who
decided to unpot. It's old stuff, but dirt doesn't go stale. I've got
some of the real deal then -- with all its mined "unreliability!"
Happy 2011 everyone
DJ
On 12/28/2010 6:25 PM, Steve Mills wrote:
> True Cornish Stone hasn't been available in the UK for 20 years or more. =
What we get now is a "made-to-recipe" substitute. Consequently it is a litt=
le more reliable than the "true" mined version
>
> Steve Mills
> Bath
> UK
>
> On 28 Dec 2010, at 20:06, John Britt wrote:
>
>> I have heard that Cornwall Stone is no longer available and wanted to se=
e if
>> anyone else has heard that? Highwater Clay only sells 10 lbs at a time =
now.
>>
>> John Britt
>> www.johnbrittpottery.com
Richard White on wed 29 dec 10
John, it is so. We have no more ghastley borate; across the pond in the
mother country, they have no more cornish stone. Perhaps the ceramics
industry over there has come up with a collection of blended/fritted
substitutes just as we now have Laguna, Murray's, Gillespie, CadyCal, etc=
=3D
.
as ghastley subs. A blended sub I have used for the cornish is:
Custer - 19
NC 4 - 45
EPK - 11
Silica - 22
Wollastonite - 3
(And then we got 50 lbs of it from our sister campus after the fire marsh=
=3D
all
told them to get all the excess stuff out of the electrical closet... wan=
=3D
t
some old Buckingham spar? or maybe some Clinchfield (but no idea if it's
#202 or #303...)? Got 50 lbs of those too...)
cheers
dw
Steve Mills on wed 29 dec 10
True Cornish Stone hasn't been available in the UK for 20 years or more. Wh=
a=3D
t we get now is a "made-to-recipe" substitute. Consequently it is a little =
m=3D
ore reliable than the "true" mined version
Steve Mills
Bath
UK
On 28 Dec 2010, at 20:06, John Britt wrote:
> I have heard that Cornwall Stone is no longer available and wanted to see=
i=3D
f=3D20
> anyone else has heard that? Highwater Clay only sells 10 lbs at a time n=
o=3D
w.
>=3D20
> John Britt
> www.johnbrittpottery.com
Larry Kruzan on thu 30 dec 10
This past winter/spring we RVed to the southwest and looped north to Reno N=
V
as we journeyed. I visited as many potters as I could and bought as much
pottery as I could - until the Travel Trailer groaned. LOL While we were in
Reno, we paid a visit to Paul Hermans pottery - loved the wood kiln and got
there just in time for his spring open house. As I poked around in Paul's
studio his permission - with his permission, of course) I noticed that he
seemed to buy a lot of materials in pallet loads.
He was not alone. Many of the potters we visited with had pallets of
materials - the ones THEY need all the time.
Makes a lot of sense in these days when the mines we depend on are closing
so often. We are in a materials driven industry where we are the small fish
in the pond.
I now have two or three bags of all the minerals I use for my base glazes
and I'm working on more as time goes on.
If I'm ordering a pallet of anything - I add a couple bags of ____ that I
use a lot of. I have two bags of original Talc that I'd bought before that
source dried up and it was "reconfigured". I hope it lasts a while - long
enough for the mine to be reopened?? I don't know but I hope so.
Very little cornball's gets used here but I do have a 5 gallon bucket of
it...Just in case.
Larry Kruzan
Lost Creek Pottery
www.lostcreekpottery.com
John Britt on thu 30 dec 10
DW,
Thanks for the info.=3D20
I know about the DF Cornwall but I talked to Jeff Zamek, who often works =
=3D
with=3D20
Hammill & Gillespie, and he indicated that all Cornwall Stone will so=3D
on be unavailable.=3D20=3D20
Thanks for the info.
John Britt
www.johnbrittpottery.com
Richard White on thu 30 dec 10
I have received several replies off-list (or so it would seem, maybe thos=
=3D
e
replies will show up on the list in the fullness of time...) asking
questions that might be of general interest, so I'll bring them back here=
=3D
.
Dan Hill asked about the blue cornwall stone of long ago. The blue tint w=
=3D
as
from fluorine in that particular mineral. The fluorine had no effect on t=
=3D
he
ceramic properties and burned off during the firing. It was the unique bl=
=3D
end
of other fluxes that made this material useful for ceramics. There were
other products called cornwall stone being sold at the time that were not=
=3D
blue. Those were either calcined (which drove off the fluorine, among oth=
=3D
er
things), or from a mine farther from the motherlode of the fluorospar and=
=3D
thus had less (or none) of the fluorine but still contained a similar
composition of the other oxides. It was a variable material, depending on=
=3D
which mine it came from and/or when it was extracted, but it had some use=
=3D
ful
properties in clay bodies and glazes.
Lee Love asked what is NC-4 in my blended sub. NC-4 is the old name of a
soda spar now marketed as Minspar. Given the variability of the original
cornish stone, I suspect any soda spar could be used, and any potash spar=
=3D
could be used for the Custer in my list. I know there are other home-brew=
=3D
recipes out there purporting to be a cornwall sub, but again, given the
variability of the original, I'm sure any of those recipes are good ones
too. I could have tweaked mine with some dolomite or some talc or a littl=
=3D
e
of this and that so as to introduce traces of who-knows what, but I tried=
=3D
to
keep this one as simple as possible with as few ingredients as possible.
cheers
dw
On Wed, 29 Dec 2010 09:22:38 -0500, Richard White wr=
=3D
ote:
>John, it is so. We have no more ghastley borate; across the pond in the
>mother country, they have no more cornish stone. Perhaps the ceramics
>industry over there has come up with a collection of blended/fritted
>substitutes just as we now have Laguna, Murray's, Gillespie, CadyCal, et=
=3D
c.
>as ghastley subs. A blended sub I have used for the cornish is:
>
>Custer - 19
>NC 4 - 45
>EPK - 11
>Silica - 22
>Wollastonite - 3
>
>(And then we got 50 lbs of it from our sister campus after the fire mars=
=3D
hall
>told them to get all the excess stuff out of the electrical closet... wa=
=3D
nt
>some old Buckingham spar? or maybe some Clinchfield (but no idea if it's=
=3D
>#202 or #303...)? Got 50 lbs of those too...)
>
>cheers
>dw
Steve Mills on thu 30 dec 10
There were two versions of the original Cornish (Cornwall) stone available=
o=3D
ver here, both with the Flourine content, marketed as Hard Purple, & Mild P=
u=3D
rple (now long gone!). I was never able to distinguish between them, but th=
e=3D
n my glazes then used little of either!
What we have here now is white and undistinguishable from almost anything e=
l=3D
se!
Steve M
Steve Mills
Bath
UK
On 30 Dec 2010, at 16:05, Richard White wrote:
> I have received several replies off-list (or so it would seem, maybe thos=
e=3D
> replies will show up on the list in the fullness of time...) asking
> questions that might be of general interest, so I'll bring them back here=
.=3D
>=3D20
> Dan Hill asked about the blue cornwall stone of long ago. The blue tint w=
a=3D
s
> from fluorine in that particular mineral. The fluorine had no effect on t=
h=3D
e
> ceramic properties and burned off during the firing. It was the unique bl=
e=3D
nd
> of other fluxes that made this material useful for ceramics. There were
> other products called cornwall stone being sold at the time that were not
> blue. Those were either calcined (which drove off the fluorine, among oth=
e=3D
r
> things), or from a mine farther from the motherlode of the fluorospar and
> thus had less (or none) of the fluorine but still contained a similar
> composition of the other oxides. It was a variable material, depending on
> which mine it came from and/or when it was extracted, but it had some use=
f=3D
ul
> properties in clay bodies and glazes.
>=3D20
> Lee Love asked what is NC-4 in my blended sub. NC-4 is the old name of a
> soda spar now marketed as Minspar. Given the variability of the original
> cornish stone, I suspect any soda spar could be used, and any potash spar
> could be used for the Custer in my list. I know there are other home-brew
> recipes out there purporting to be a cornwall sub, but again, given the
> variability of the original, I'm sure any of those recipes are good ones
> too. I could have tweaked mine with some dolomite or some talc or a littl=
e=3D
> of this and that so as to introduce traces of who-knows what, but I tried=
t=3D
o
> keep this one as simple as possible with as few ingredients as possible.
>=3D20
> cheers
> dw
>=3D20
>=3D20
>=3D20
> On Wed, 29 Dec 2010 09:22:38 -0500, Richard White wr=
o=3D
te:
>=3D20
>> John, it is so. We have no more ghastley borate; across the pond in the
>> mother country, they have no more cornish stone. Perhaps the ceramics
>> industry over there has come up with a collection of blended/fritted
>> substitutes just as we now have Laguna, Murray's, Gillespie, CadyCal, et=
c=3D
.
>> as ghastley subs. A blended sub I have used for the cornish is:
>>=3D20
>> Custer - 19
>> NC 4 - 45
>> EPK - 11
>> Silica - 22
>> Wollastonite - 3
>>=3D20
>> (And then we got 50 lbs of it from our sister campus after the fire mars=
h=3D
all
>> told them to get all the excess stuff out of the electrical closet... wa=
n=3D
t
>> some old Buckingham spar? or maybe some Clinchfield (but no idea if it's
>> #202 or #303...)? Got 50 lbs of those too...)
>>=3D20
>> cheers
>> dw
John Rodgers on thu 30 dec 10
I would think that a combination of substitutes for Cornwall Stone
could be found .... a mix of other minerals added to a glaze to get the
same effect. Not being much or a chemist, I wouldn't know where to go
for the solution but it just seems that way to me.
John
John Rodgers
Clayartist and Moldmaker
88'GL VW Bus Driver
Chelsea, AL
Http://www.moldhaus.com
On 12/30/2010 1:14 PM, Steve Mills wrote:
> There were two versions of the original Cornish (Cornwall) stone availab=
le over here, both with the Flourine content, marketed as Hard Purple,& Mi=
ld Purple (now long gone!). I was never able to distinguish between them, b=
ut then my glazes then used little of either!
> What we have here now is white and undistinguishable from almost anything=
else!
>
> Steve M
>
>
> Steve Mills
> Bath
> UK
>
> On 30 Dec 2010, at 16:05, Richard White wrote:
>
>> I have received several replies off-list (or so it would seem, maybe tho=
se
>> replies will show up on the list in the fullness of time...) asking
>> questions that might be of general interest, so I'll bring them back her=
e.
>>
>> Dan Hill asked about the blue cornwall stone of long ago. The blue tint =
was
>> from fluorine in that particular mineral. The fluorine had no effect on =
the
>> ceramic properties and burned off during the firing. It was the unique b=
lend
>> of other fluxes that made this material useful for ceramics. There were
>> other products called cornwall stone being sold at the time that were no=
t
>> blue. Those were either calcined (which drove off the fluorine, among ot=
her
>> things), or from a mine farther from the motherlode of the fluorospar an=
d
>> thus had less (or none) of the fluorine but still contained a similar
>> composition of the other oxides. It was a variable material, depending o=
n
>> which mine it came from and/or when it was extracted, but it had some us=
eful
>> properties in clay bodies and glazes.
>>
>> Lee Love asked what is NC-4 in my blended sub. NC-4 is the old name of a
>> soda spar now marketed as Minspar. Given the variability of the original
>> cornish stone, I suspect any soda spar could be used, and any potash spa=
r
>> could be used for the Custer in my list. I know there are other home-bre=
w
>> recipes out there purporting to be a cornwall sub, but again, given the
>> variability of the original, I'm sure any of those recipes are good ones
>> too. I could have tweaked mine with some dolomite or some talc or a litt=
le
>> of this and that so as to introduce traces of who-knows what, but I trie=
d to
>> keep this one as simple as possible with as few ingredients as possible.
>>
>> cheers
>> dw
>>
>>
>>
>> On Wed, 29 Dec 2010 09:22:38 -0500, Richard White w=
rote:
>>
>>> John, it is so. We have no more ghastley borate; across the pond in the
>>> mother country, they have no more cornish stone. Perhaps the ceramics
>>> industry over there has come up with a collection of blended/fritted
>>> substitutes just as we now have Laguna, Murray's, Gillespie, CadyCal, e=
tc.
>>> as ghastley subs. A blended sub I have used for the cornish is:
>>>
>>> Custer - 19
>>> NC 4 - 45
>>> EPK - 11
>>> Silica - 22
>>> Wollastonite - 3
>>>
>>> (And then we got 50 lbs of it from our sister campus after the fire mar=
shall
>>> told them to get all the excess stuff out of the electrical closet... w=
ant
>>> some old Buckingham spar? or maybe some Clinchfield (but no idea if it'=
s
>>> #202 or #303...)? Got 50 lbs of those too...)
>>>
>>> cheers
>>> dw
>
Ron Roy on fri 31 dec 10
Hi John,
Calculation software would be the way to do it - RR
Quoting John Rodgers :
> I would think that a combination of substitutes for Cornwall Stone
> could be found .... a mix of other minerals added to a glaze to get the
> same effect. Not being much or a chemist, I wouldn't know where to go
> for the solution but it just seems that way to me.
>
> John
>
> John Rodgers
Lee Love on fri 31 dec 10
there are a zillion substitution recipes out there.
--
=3DA0Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
John Britt on fri 31 dec 10
Ron,
I am not trying to reproduce it, but rather find out if it is true that i=
=3D
t is no longer=3D20
available.=3D20
Thanks,
John Britt
www.johnbrittpottery.com
John Britt on mon 3 jan 11
Got a note from H &G:
John,
Sorry for the late reply, I was away on vacation. The information regard=
=3D
ing=3D20
Cornwall Stone is correct, the mine in the UK has been closed. H&G i=3D
s currently=3D20
working on a substitution from this region and I will have additional inf=
=3D
ormation=3D20
shortly.
=3D20
Regards,
Kraig Hall&G
| |
|
