Ben Friesen on fri 21 jan 05
Maybe there's something I can do to stop the crazing as well...? I use =
Laguna B-mix 5...... fired to cone 6 oxidation...=20
Here's the recipe if someone's got an idea..
Custer Feldspar 44.0 %
Kaolin 6.0
Bentonite 2.0
Lithium Carbonate 4.0
Calcium Carbonate 14.0
Zinc Oxide 5.0
Silica 24.0
RIO 6.0
Tit. Dioxide 2.5
Thanks,
Ben Friesen
Stonepath Pottery
Abbotsford, BC, Canada
Daniel Semler on sat 22 jan 05
Hi Ben
First, a couple of things :
- your base recipe excluding suspenders, colourants etc totals 97. I've stuck
with that here but you could retotal to 100. I would not normally include
bentonite in the base glaze.
- Kaolins vary - I've assumed Edgar Plastic Kaolin (EPK) but if you're using
something different, results may be a bit off.
- I assumed whiting for calcium carb as that would be common, unless your
using seashells :)
- I'm not familiar with Bmix 5 so I'm just guessing an expansion range that
would be good to run blends over, based on data in RR and JH's book.
Custer Feldspar 38.60
Kaolin 9.50
Lithium Carbonate 11.00
Calcium Carbonate 6.10
Zinc Oxide 5.00
Silica 27.50
TOTAL 97.70
The above has pretty much made the Li2O the primary flux. Lith carb has some
water solubility and can give odd results - shivering etc. Anyhow what I would
suggest is to take the original and the mod above and run line blend between
them. The orig has a COE of about 513 and the mod above about 428. Hopefully
somewhere in between you'll get what you need. If not it should at least be
clear that the crazing is becoming much less dense.
I was playing with Spodumene as a way to eliminate the Li2CO3 but until you
know what you're shooting for in expansion I'd only end up with a blend with
both spod and lith carb in it. Better probably to run the blends and get the
expansion sorted and then re-cast it with spod if you are concerned about
solubility/toxicity of lithium carb.
HTH
D
David Hewitt on sun 23 jan 05
Ben,
You might like to try reducing the Calcium carbonate to say 7 parts and
adding some 10 parts of a low expansion frit such as Potclays 2279. This
would significantly reduce the coefficient of expansion. Whether or not
it would enable your glaze to fit your body I cannot say, but it is
altering the glaze recipe in the right direction.
David
In message , Ben Friesen writes
>Maybe there's something I can do to stop the crazing as well...? I use
>Laguna B-mix 5...... fired to cone 6 oxidation...
>
>Here's the recipe if someone's got an idea..
>
>Custer Feldspar 44.0 %
>Kaolin 6.0
>Bentonite 2.0
>Lithium Carbonate 4.0
>Calcium Carbonate 14.0
>Zinc Oxide 5.0
>Silica 24.0
>
>RIO 6.0
>Tit. Dioxide 2.5
>
>Thanks,
>Ben Friesen
>Stonepath Pottery
>Abbotsford, BC, Canada
--
David Hewitt
Web:- http://www.dhpot.demon.co.uk
Ron Roy on sun 23 jan 05
Hi Ben,
First I don't like using more than 2% Lithium Carb - it can be a disaster
with some clay bodies.
I have lowered the expansion a lot so you had best do a line blend with
this glaze and the original to see where the crazing stops.
The expansion of this glaze will be way too low without the iron by the way
- if you ever give it to someone you should include a warning.
Custer - 9.0
Spodumene - 31.0
Lithium carb - 2.0
Whiting - 15.5
Zinc - 6.0
OM4 - 4.0 (I used OM because the amount of kaolin was getting low)
Silica - 32.5
Bentonite - 2.0
Red iron - 6.0
TiO2 - 2.5
Total - 110.5
By the way - has anyone from Laguna offered to help?
RR
>Maybe there's something I can do to stop the crazing as well...? I use
>Laguna B-mix 5...... fired to cone 6 oxidation...
>
>Here's the recipe if someone's got an idea..
>
>Custer Feldspar 44.0 %
>Kaolin 6.0
>Bentonite 2.0
>Lithium Carbonate 4.0
>Calcium Carbonate 14.0
>Zinc Oxide 5.0
>Silica 24.0
>
>RIO 6.0
>Tit. Dioxide 2.5
>
>Thanks,
>Ben Friesen
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Ben Friesen on wed 26 jan 05
Thanks Ron... I'll give this one a try as well. The glaze is actually from
Michael Bailey's book.. the Transparent 12 glaze. I checked the recipe again
and it only comes out to a total of 99. Something's missing I guess...
Anyway... I also haven't had that good of luck with glazes using Lithium
Carb.... And no, I haven't heard anything from Laguna.
Thanks again,
Ben
----- Original Message -----
From: "Ron Roy"
To:
Sent: Sunday, January 23, 2005 11:13 AM
Subject: Re: stopping the craze.... addendum to crazing affecting strength
> Hi Ben,
>
> First I don't like using more than 2% Lithium Carb - it can be a disaster
> with some clay bodies.
>
> I have lowered the expansion a lot so you had best do a line blend with
> this glaze and the original to see where the crazing stops.
>
> The expansion of this glaze will be way too low without the iron by the
way
> - if you ever give it to someone you should include a warning.
>
> Custer - 9.0
> Spodumene - 31.0
> Lithium carb - 2.0
> Whiting - 15.5
> Zinc - 6.0
> OM4 - 4.0 (I used OM because the amount of kaolin was getting low)
> Silica - 32.5
> Bentonite - 2.0
> Red iron - 6.0
> TiO2 - 2.5
> Total - 110.5
>
> By the way - has anyone from Laguna offered to help?
>
> RR
>
> >Maybe there's something I can do to stop the crazing as well...? I use
> >Laguna B-mix 5...... fired to cone 6 oxidation...
> >
> >Here's the recipe if someone's got an idea..
> >
> >Custer Feldspar 44.0 %
> >Kaolin 6.0
> >Bentonite 2.0
> >Lithium Carbonate 4.0
> >Calcium Carbonate 14.0
> >Zinc Oxide 5.0
> >Silica 24.0
> >
> >RIO 6.0
> >Tit. Dioxide 2.5
> >
> >Thanks,
> >Ben Friesen
>
> Ron Roy
> RR#4
> 15084 Little Lake Road
> Brighton, Ontario
> Canada
> K0K 1H0
> Phone: 613-475-9544
> Fax: 613-475-3513
>
>
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