Lee Taylor on wed 9 mar 11
I have several clay body recipes that call for equal parts of sand and gr=
=3D
og in=3D20
the mix. These clays containing grog are much more abraisive and=3D20
unpleasant to work with. The grog is eating my fingernails! Is there so=
=3D
me=3D20
reason that river sand (so long as it is stable to the maturing temp of t=
=3D
he=3D20
clay) could not be used exclusively? I have heard that sand (quartz/sili=
=3D
ca) is=3D20
not reactive in a clay body unless 325 mesh or finer. Is this true? It =
=3D
also=3D20
seems that the crushed firebrick, from which the grog is made, has alread=
=3D
y=3D20
been fired to a higher temp than I will be firing, so it would be non-rea=
=3D
ctive,=3D20
as well. This clay is to be wood fired, if that makes any difference. M=
=3D
y=3D20
fingernails will appreciate your reply.
Lee Taylor
Lexington, Virginia
David Beumee on wed 9 mar 11
Hi Lee,
On one hand I see no reason why commonly available 90 mesh silica sand
could not be used successfully and exclusively in your recipe, but on the
other hand, there may well be a good reason why a balance of grog and sand
is called for in your recipe. 100 mesh Mullite grog is available from the
Virginia based Kyanite Corp., and depending on percentage content, you can
hardly feel it, as is the case with 90 mesh sand.
David Beumee
Lafayette, CO
On Wed, Mar 9, 2011 at 6:25 AM, Lee Taylor wrote=
:
> I have several clay body recipes that call for equal parts of sand and gr=
og
> in
> the mix. These clays containing grog are much more abraisive and
> unpleasant to work with. The grog is eating my fingernails! Is there so=
me
> reason that river sand (so long as it is stable to the maturing temp of t=
he
> clay) could not be used exclusively? I have heard that sand
> (quartz/silica) is
> not reactive in a clay body unless 325 mesh or finer. Is this true? It
> also
> seems that the crushed firebrick, from which the grog is made, has alread=
y
> been fired to a higher temp than I will be firing, so it would be
> non-reactive,
> as well. This clay is to be wood fired, if that makes any difference. M=
y
> fingernails will appreciate your reply.
>
> Lee Taylor
> Lexington, Virginia
>
Ron Roy on wed 9 mar 11
Hi Lee,
Lots of potters use sand in their clay bodies - just keep in mind -
all those grains of quartz will go through the quartz inversion at
573C on the way down during bisque and glaze fire cooling.
This can lead to dunting so the amount of sand has a practical limit.
The bigger the pots and the sand the more likely there could be a
problem.
Wood firing kilns cool more slowly in most cases so that would tend to
limit the problem.
How much sand you thinking of adding?
RR
Quoting Lee Taylor :
> I have several clay body recipes that call for equal parts of sand
> and grog in
> the mix. These clays containing grog are much more abraisive and
> unpleasant to work with. The grog is eating my fingernails! Is there so=
me
> reason that river sand (so long as it is stable to the maturing temp of t=
he
> clay) could not be used exclusively? I have heard that sand
> (quartz/silica) is
> not reactive in a clay body unless 325 mesh or finer. Is this true? It =
also
> seems that the crushed firebrick, from which the grog is made, has alread=
y
> been fired to a higher temp than I will be firing, so it would be
> non-reactive,
> as well. This clay is to be wood fired, if that makes any difference. M=
y
> fingernails will appreciate your reply.
>
> Lee Taylor
> Lexington, Virginia
>
Steve Mills on thu 10 mar 11
David Frith, a notable UK Potter makes his own grog out of his wheel trimmi=
n=3D
gs. He biscuit fires them to about 850oC and then grinds them down with a c=
o=3D
rn mill.=3D20
The resulting grog is MUCH kinder to hands and nails as well as adding stre=
n=3D
gth to the clay. When fired you wouldn't know it was there!=3D20
I used to add sand to my clay, but found I needed more of that than grog to=
a=3D
chieve the desired result.=3D20
I now make my own!!
Steve M
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my Ipod touch
On 9 Mar 2011, at 13:25, Lee Taylor wrote:
> I have several clay body recipes that call for equal parts of sand and gr=
o=3D
g in=3D20
> the mix. These clays containing grog are much more abraisive and=3D20
> unpleasant to work with. The grog is eating my fingernails! Is there so=
m=3D
e=3D20
> reason that river sand (so long as it is stable to the maturing temp of t=
h=3D
e=3D20
> clay) could not be used exclusively? I have heard that sand (quartz/sili=
c=3D
a) is=3D20
> not reactive in a clay body unless 325 mesh or finer. Is this true? It =
a=3D
lso=3D20
> seems that the crushed firebrick, from which the grog is made, has alread=
y=3D
=3D20
> been fired to a higher temp than I will be firing, so it would be non-rea=
c=3D
tive,=3D20
> as well. This clay is to be wood fired, if that makes any difference. M=
y=3D
=3D20
> fingernails will appreciate your reply.
>=3D20
> Lee Taylor
> Lexington, Virginia
douglas fur on fri 11 mar 11
Along these lines Cardew used to grades of grog at Wenford Bridge.
Soft grog- sintered clay from sealing the areas around the door and
fireboxes in bodies. This had the easy on he hands feel Steve mentions
Hard grog- wads and broken saggars from the high fire chamber recycled into
refractories. definitely nasty on the hands. This sounds like Lee's
experience with firebrick derived grog.
The dave Firth method is appealing in that it's the same clay as the body
DRB
Seola Creek
On Wed, Mar 9, 2011 at 4:35 PM, Steve Mills
wrote:
> David Frith, a notable UK Potter makes his own grog out of his wheel
> trimmings. He biscuit fires them to about 850oC and then grinds them down
> with a corn mill.
> The resulting grog is MUCH kinder to hands and nails as well as adding
> strength to the clay. When fired you wouldn't know it was there!
> I used to add sand to my clay, but found I needed more of that than grog =
to
> achieve the desired result.
> I now make my own!!
>
> Steve M
>
> Steve Mills
> Bath
> UK
> www.mudslinger.me.uk
> Sent from my Ipod touch
>
> On 9 Mar 2011, at 13:25, Lee Taylor wrote:
>
> > I have several clay body recipes that call for equal parts of sand and
> grog in
> > the mix. These clays containing grog are much more abraisive and
> > unpleasant to work with. The grog is eating my fingernails! Is there
> some
> > reason that river sand (so long as it is stable to the maturing temp of
> the
> > clay) could not be used exclusively? I have heard that sand
> (quartz/silica) is
> > not reactive in a clay body unless 325 mesh or finer. Is this true? I=
t
> also
> > seems that the crushed firebrick, from which the grog is made, has
> already
> > been fired to a higher temp than I will be firing, so it would be
> non-reactive,
> > as well. This clay is to be wood fired, if that makes any difference.
> My
> > fingernails will appreciate your reply.
> >
> > Lee Taylor
> > Lexington, Virginia
>
Lee on sun 13 mar 11
On Sun, Mar 13, 2011 at 5:49 PM, Eric Hansen
wrote:
>
> the other hand, Shgaraki and Iga clay is hard on the hands so potters
> there use a combinbation of hand-building and wheel throwing instead
> for trying to do it all on the wheel. My brother used to use a lot of
> that "bad" grog, they simply used credit cards for most of their
> throwing.
Shigaraki is not too hard on your hands. =3DC2=3DA0 Crushed feldspar is a
little harder. =3DC2=3DA0 I just came in from throwing with crushed Custer =
and
mica.
If typical grog is too hard on your hands, you might be throwing at
too fast a speed. =3DC2=3DA0There is no problem with this on a Leach or Kor=
ean
wheel. =3DC2=3DA0On electric, you just have to stifle your speed.
If you have problems slowing down. I have a book and CD checked
out from the library you need to read and listen to ;^) :
In praise of slowness : how a worldwide movement is challenging the
cult of speed
by=3DC2=3DA0Honore=3DCC=3D81, Carl.Comment
The power of slow : [finding balance and fulfillment beyond the cult
of speed] by=3DC2=3DA0Honore=3DCC=3D81, Carl.Comment
--
=3DC2=3DA0Lee Love in Minneapolis
http://mingeisota.blogspot.com/
=3DC2=3DA0"Ta tIr na n-=3DC3=3DB3g ar chul an tI=3DE2=3D80=3D94tIr dlainn t=
rina ch=3DC3=3DA9i=3D
le"=3DE2=3D80=3D94that is, "The
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
Eric Hansen on sun 13 mar 11
So for example one could use nice ocean or river sand of the
appropriate mesh size (no fines) I think the consensus was 100 - 200
mesh & them make up the balance with calcined clay such as Glo Max or
another calcined clay product. This would be easier on the hands. On
the other hand, Shgaraki and Iga clay is hard on the hands so potters
there use a combinbation of hand-building and wheel throwing instead
for trying to do it all on the wheel. My brother used to use a lot of
that "bad" grog, they simply used credit cards for most of their
throwing.
- h a n s e n -
On Fri, Mar 11, 2011 at 1:47 PM, douglas fur <23drb50@gmail.com> wrote:
> Along these lines Cardew used to grades of grog at Wenford Bridge.
> Soft grog- sintered clay from sealing the areas around the door and
> fireboxes in bodies. This had the easy on he hands feel Steve mentions
> Hard grog- wads and broken saggars from the high fire chamber recycled in=
=3D
to
> refractories. definitely nasty on the hands. =3DA0This sounds like Lee's
> experience with firebrick derived grog.
>
> The dave Firth method is appealing in that it's the same clay as the body
> DRB
> Seola Creek
>
> On Wed, Mar 9, 2011 at 4:35 PM, Steve Mills
> wrote:
>
>> David Frith, a notable UK Potter makes his own grog out of his wheel
>> trimmings. He biscuit fires them to about 850oC and then grinds them dow=
=3D
n
>> with a corn mill.
>> The resulting grog is MUCH kinder to hands and nails as well as adding
>> strength to the clay. When fired you wouldn't know it was there!
>> I used to add sand to my clay, but found I needed more of that than grog=
=3D
to
>> achieve the desired result.
>> I now make my own!!
>>
>> Steve M
>>
>> Steve Mills
>> Bath
>> UK
>> www.mudslinger.me.uk
>> Sent from my Ipod touch
>>
>> On 9 Mar 2011, at 13:25, Lee Taylor wrote:
>>
>> > I have several clay body recipes that call for equal parts of sand and
>> grog in
>> > the mix. =3DA0 These clays containing grog are much more abraisive and
>> > unpleasant to work with. =3DA0The grog is eating my fingernails! =3DA0=
Is t=3D
here
>> some
>> > reason that river sand (so long as it is stable to the maturing temp o=
=3D
f
>> the
>> > clay) could not be used exclusively? =3DA0I have heard that sand
>> (quartz/silica) is
>> > not reactive in a clay body unless 325 mesh or finer. =3DA0Is this tru=
e?=3D
=3DA0It
>> also
>> > seems that the crushed firebrick, from which the grog is made, has
>> already
>> > been fired to a higher temp than I will be firing, so it would be
>> non-reactive,
>> > as well. =3DA0This clay is to be wood fired, if that makes any differe=
nc=3D
e.
>> =3DA0My
>> > fingernails will appreciate your reply.
>> >
>> > Lee Taylor
>> > Lexington, Virginia
>>
>
--=3D20
Eric Alan Hansen
Stonehouse Studio Pottery
Alexandria, Virginia
americanpotter.blogspot.com
thesuddenschool.blogspot.com
hansencookbook.blogspot.com
"Simplify, simplify, simplify" - Thoreau
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