Gail Dapogny on fri 13 aug 99
I'm looking for a c 9/10 satin matte dk green glaze, and recently someone
mentioned to me an old glaze by Don Reitz. Does anyone have the formula
for this? Any similar glazes would also be appreciated.
Glazes of this type are (can be) a nice rich dk green, not too dry, but not
shiny,that goes black where thick. Currently I've been working with an old
Shaner Red glaze, modified to be green. Also sometimes it seems to have a
whitish cast on the surface. It can be very nice but I'm mainly having
lots of trouble with pinhoes and some blistering. Wish I knew why...
Anyway, I'd really like to compare and try the Reitz glaze.
The altered Shaner glaze (c 9/10) is as follows:
potash feldspar 52.7
talc 4.0
bone ash 4.0
whiting 21.3
EPK 25.0
total 107
plus 4 - 5% copper carb
Thanks in advance.
--Gail
Gail Dapogny
1154 Olden Road
Ann Arbor, MI 48103-3005
(734) 665-9816
gdapogny@umich.edu
Hank Murrow on sat 14 aug 99
>----------------------------Original message----------------------------
>I'm looking for a c 9/10 satin matte dk green glaze, and recently someone
>mentioned to me an old glaze by Don Reitz. Does anyone have the formula
>for this?
Dear Gail; Here's a Reitz glaze which I got from Jim Robinson via Pete
Pinnell. It is a everchangingly consistent beauty; and that's not an
oxymoron, just great glaze
Nepheline Syenite 70
Petalite 15
Whiting 5
Gerstley Borate 2
Grolleg Kaolin 8
Cobalt Carbonate 1
Rutile
I fire it in oxidation @ C/10 but please tell me how it works in your fire.
Bon apetit! Hank Murrow in Eugene
Mike Bailey on sat 14 aug 99
In message , Gail Dapogny writes
Dear Gail,
A few thoughts re. your glaze pinholing problem.
1. The glaze is high in alumina and low in silica. David Hewitt's glaze
calculating program gave as a unity formula
1.00 fluxes : 0.51 Al2O3 : 2.18 SiO2
Whereas a transparent, fully melted glaze (eutectic point) would be
something like:
1.00 fluxes : 0.45 Al2O3 : 3.6 SiO2
or if you work in % analysis this glaze =
25% flux; 21% alumina: 54% silica
and a transparent, fully melted glaze (eutectic point) would be
something like:
24% flux; 12% alumina: 64% silica
Adding just silica to this glaze would take it towards the eutectic. A
test adding increments of 2% of silica in 10 steps (taking it up to 20
parts added) would gradually make it less matt, slightly more fluxed /
satiny. The slightly better melt might be enough to stop the blisters.
2.Firing higher would also smooth the glaze out more.
3. Sometimes the remnants of carbonates or sulphates in the body produce
blisters - this defect can be cured by soaking the bisque.
4. I doubt if it's the copper carb giving off CO2 as this would have
happened well before the glaze started to heal over.
It's easier to give a more accurate diagnosis if one can see the problem
but I hope one of the above might be a possible explanation. I'll be
interested to see what anyone else thinks.
Cheers,
Mike.
>----------------------------Original message----------------------------
>I'm looking for a c 9/10 satin matte dk green glaze, and recently someone
>mentioned to me an old glaze by Don Reitz. Does anyone have the formula
>for this? Any similar glazes would also be appreciated.
>Glazes of this type are (can be) a nice rich dk green, not too dry, but not
>shiny,that goes black where thick. Currently I've been working with an old
>Shaner Red glaze, modified to be green. Also sometimes it seems to have a
>whitish cast on the surface. It can be very nice but I'm mainly having
>lots of trouble with pinhoes and some blistering. Wish I knew why...
>Anyway, I'd really like to compare and try the Reitz glaze.
>
>The altered Shaner glaze (c 9/10) is as follows:
>
>potash feldspar 52.7
>talc 4.0
>bone ash 4.0
>whiting 21.3
>EPK 25.0
>
>total 107
>
>plus 4 - 5% copper carb
>
>Thanks in advance.
>--Gail
>
>Gail Dapogny
>1154 Olden Road
>Ann Arbor, MI 48103-3005
>(734) 665-9816
>gdapogny@umich.edu
>
--
Mike Bailey. Bath. U.K.
Julia M. Townsend on sun 15 aug 99
ok group..... I would like a glaze like this in ^6. Anyone have one or know
how to change this one to lower the melting temperature?
thanks to all
JuliE
Hank Murrow wrote:
> ----------------------------Original message----------------------------
> >----------------------------Original message----------------------------
> >I'm looking for a c 9/10 satin matte dk green glaze, and recently someone
> >mentioned to me an old glaze by Don Reitz. Does anyone have the formula
> >for this?
>
> Dear Gail; Here's a Reitz glaze which I got from Jim Robinson via Pete
> Pinnell. It is a everchangingly consistent beauty; and that's not an
> oxymoron, just great glaze
>
> Nepheline Syenite 70
> Petalite 15
> Whiting 5
> Gerstley Borate 2
> Grolleg Kaolin 8
> Cobalt Carbonate 1
> Rutile
>
> I fire it in oxidation @ C/10 but please tell me how it works in your fire.
> Bon apetit! Hank Murrow in Eugene
ginny bivaletz on sun 15 aug 99
mike, could you please explain more about "soaking the bisque"? thanks,
ginny
--- Mike Bailey wrote:
> ----------------------------Original
> message----------------------------
> In message , Gail Dapogny
> writes
> Dear Gail,
>
> A few thoughts re. your glaze pinholing problem.
>
> 1. The glaze is high in alumina and low in silica.
> David Hewitt's glaze
> calculating program gave as a unity formula
> 1.00 fluxes : 0.51 Al2O3 : 2.18 SiO2
>
> Whereas a transparent, fully melted glaze (eutectic
> point) would be
> something like:
> 1.00 fluxes : 0.45 Al2O3 : 3.6 SiO2
>
> or if you work in % analysis this glaze =
> 25% flux; 21% alumina: 54% silica
>
> and a transparent, fully melted glaze (eutectic
> point) would be
> something like:
> 24% flux; 12% alumina: 64% silica
>
> Adding just silica to this glaze would take it
> towards the eutectic. A
> test adding increments of 2% of silica in 10 steps
> (taking it up to 20
> parts added) would gradually make it less matt,
> slightly more fluxed /
> satiny. The slightly better melt might be enough to
> stop the blisters.
>
> 2.Firing higher would also smooth the glaze out
> more.
>
> 3. Sometimes the remnants of carbonates or sulphates
> in the body produce
> blisters - this defect can be cured by soaking the
> bisque.
>
> 4. I doubt if it's the copper carb giving off CO2 as
> this would have
> happened well before the glaze started to heal over.
>
> It's easier to give a more accurate diagnosis if one
> can see the problem
> but I hope one of the above might be a possible
> explanation. I'll be
> interested to see what anyone else thinks.
>
> Cheers,
>
> Mike.
>
>
>
>
> >----------------------------Original
> message----------------------------
> >I'm looking for a c 9/10 satin matte dk green
> glaze, and recently someone
> >mentioned to me an old glaze by Don Reitz. Does
> anyone have the formula
> >for this? Any similar glazes would also be
> appreciated.
> >Glazes of this type are (can be) a nice rich dk
> green, not too dry, but not
> >shiny,that goes black where thick. Currently I've
> been working with an old
> >Shaner Red glaze, modified to be green. Also
> sometimes it seems to have a
> >whitish cast on the surface. It can be very nice
> but I'm mainly having
> >lots of trouble with pinhoes and some blistering.
> Wish I knew why...
> >Anyway, I'd really like to compare and try the
> Reitz glaze.
> >
> >The altered Shaner glaze (c 9/10) is as follows:
> >
> >potash feldspar 52.7
> >talc 4.0
> >bone ash 4.0
> >whiting 21.3
> >EPK 25.0
> >
> >total 107
> >
> >plus 4 - 5% copper carb
> >
> >Thanks in advance.
> >--Gail
> >
> >Gail Dapogny
> >1154 Olden Road
> >Ann Arbor, MI 48103-3005
> >(734) 665-9816
> >gdapogny@umich.edu
> >
>
> --
> Mike Bailey. Bath. U.K.
>
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Mike Bailey on mon 16 aug 99
In message , Julia M. Townsend writes
Dear Julie,
The simplest way of lowering the firing temperature of a glaze is to
reduce the china clay in the recipe. I'd try this one without any china
clay in it for ^6.
You could add 2% bentonite just to help with the suspension.
If this is no good the situation then gets more complicated and you end
up reformulating and producing a different glaze anyway.
Cheers,
Mike Bailey.
>----------------------------Original message----------------------------
>ok group..... I would like a glaze like this in ^6. Anyone have one or know
>how to change this one to lower the melting temperature?
>
>thanks to all
>JuliE
>
>Hank Murrow wrote:
>
>> ----------------------------Original message----------------------------
>> >----------------------------Original message----------------------------
>> >I'm looking for a c 9/10 satin matte dk green glaze, and recently someone
>> >mentioned to me an old glaze by Don Reitz. Does anyone have the formula
>> >for this?
>>
>> Dear Gail; Here's a Reitz glaze which I got from Jim Robinson via Pete
>> Pinnell. It is a everchangingly consistent beauty; and that's not an
>> oxymoron, just great glaze
>>
>> Nepheline Syenite 70
>> Petalite 15
>> Whiting 5
>> Gerstley Borate 2
>> Grolleg Kaolin 8
>> Cobalt Carbonate 1
>> Rutile
>>
>> I fire it in oxidation @ C/10 but please tell me how it works in your fire.
>> Bon apetit! Hank Murrow in Eugene
>
--
Mike Bailey
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