Lili Krakowski on sun 1 may 11
One of the reasons so many of us hated Gerstley Borate, as much as we =3D
hated Colemanite is that the material was consistently unreliable.=3D20
We "depend" on mined materials. Not only do mine runs vary, but some =3D
materials can come from a number of different places,with different =3D
actual makeups.=3D20
Even frits are not 100% trustworthy, because--as Mr Isaacs of Hammill & =3D
Gillespie told me many years ago-- there can be variations in the =3D
materials used to make them.
Point is that one cannot, should not expect consistency. Glaze =3D
calculation helps, but offers no guarantees. (And while is is great to =3D
have a glaze calculation program, it call can be done with paper, =3D
pencil, a calculator. As you will see on my "Basic Internet Glaze =3D
Course")
Some reliability is obtained by one's buying 50 lbs sacks of material. =3D
This is super for those who can tie up the money, and have the space to =3D
store all those sacks. Most potters, I think, need to buy glaze =3D
materials in smaller quantities.
What does one do if one just has bought a new supply of X material, =3D
uses it in a glaze, and the result is different from that obtained =3D
from/in a previous batch of glaze?
Always, always keep a small supply--like 500 gms-- of each material. =3D
Store is safely and label the container not only with dealer's name, but =
=3D
the date on which you got it. =3D20
Then, when you get in a new supply of a material, and you blame it for a =
=3D
change in your glaze, you can check your observation by making up a =3D
small batch of what you had before.=3D20
IMO it also is necessary to keep a good lump of each clay =3D
body...labeled, dated. If you do not wish to keep a lump of clay, at =3D
least keep a dozen or so labeled, identifiable test tiles. Because it is =
=3D
not uncommon that your current batch of glaze disappoints not because =3D
of the just-into-the-studio material, but because of a change in the =3D
clay body.
Clay body manufacturers try to keep clay bodies constant. But they too =3D
depend on mine runs, clays going off the market, this and that....A clay =
=3D
body my look, feel, work, and fire the same color as the previous =3D
batch...but be react quite differently with glaze.
Lili Krakowski
Be of good courage
Steve Mills on mon 2 may 11
As Potters/Suppliers Kate, and I, and later Mike when he joined us, made a =
p=3D
oint of always stocking materials from the same primary source, regardless =
o=3D
f price, as we knew consistency is the most important criterion. Even so we=
a=3D
lways insisted our customers tested EVERYTHING before using it, just to be =
a=3D
bsolutely sure.=3D20
You can't "undo" a wrong glaze when it's been fired!
It's not "when in doubt, test" it's "ALWAYS test" regardless!
Steve M
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my Ipod touch
On 2 May 2011, at 00:42, Lili Krakowski wrote:
> One of the reasons so many of us hated Gerstley Borate, as much as we hat=
e=3D
d Colemanite is that the material was consistently unreliable.=3D20
>=3D20
> We "depend" on mined materials. Not only do mine runs vary, but some mat=
e=3D
rials can come from a number of different places,with different actual make=
u=3D
ps.=3D20
>=3D20
> Even frits are not 100% trustworthy, because--as Mr Isaacs of Hammill & G=
i=3D
llespie told me many years ago-- there can be variations in the materials u=
s=3D
ed to make them.
>=3D20
> Point is that one cannot, should not expect consistency. Glaze calculatio=
n=3D
helps, but offers no guarantees. (And while is is great to have a glaze c=
a=3D
lculation program, it call can be done with paper, pencil, a calculator. A=
s=3D
you will see on my "Basic Internet Glaze Course")
>=3D20
> Some reliability is obtained by one's buying 50 lbs sacks of material. T=
h=3D
is is super for those who can tie up the money, and have the space to store=
a=3D
ll those sacks. Most potters, I think, need to buy glaze materials in sma=
l=3D
ler quantities.
>=3D20
> What does one do if one just has bought a new supply of X material, uses=
i=3D
t in a glaze, and the result is different from that obtained from/in a pre=
v=3D
ious batch of glaze?
>=3D20
> Always, always keep a small supply--like 500 gms-- of each material. Sto=
r=3D
e is safely and label the container not only with dealer's name, but the da=
t=3D
e on which you got it. =3D20
>=3D20
> Then, when you get in a new supply of a material, and you blame it for a =
c=3D
hange in your glaze, you can check your observation by making up a small ba=
t=3D
ch of what you had before.=3D20
>=3D20
> IMO it also is necessary to keep a good lump of each clay body...labeled=
,=3D
dated. If you do not wish to keep a lump of clay, at least keep a dozen or=
s=3D
o labeled, identifiable test tiles. Because it is not uncommon that your cu=
r=3D
rent batch of glaze disappoints not because of the just-into-the-studio ma=
t=3D
erial, but because of a change in the clay body.
>=3D20
> Clay body manufacturers try to keep clay bodies constant. But they too d=
e=3D
pend on mine runs, clays going off the market, this and that....A clay body=
m=3D
y look, feel, work, and fire the same color as the previous batch...but be =
r=3D
eact quite differently with glaze.
>=3D20
>=3D20
>=3D20
>=3D20
>=3D20
>=3D20
> Lili Krakowski
> Be of good courage
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