Margaret Barlow on fri 4 jan 02
A while ago there was a thread on this topic and reference to the glazes
containing lithium carbonate and zinc. I knew I had experienced this
phenomenon but did not have access to my test tiles and glaze recipes for a
while, well here is the recipe that did it for me.
I do not know where the original recipe came from, it was a few years ago
and I was playing around with and learning how to use Insight, at the time,
so these are two revisions to the original recipe.
Note they do NOT contain any Zinc, just lots of Lithium Carb......
The glazes were fired to a full cone six with and without additions of
Chrome ox. 0.25
Tin 5.0
The glazes were tested on PSH clays 910 which is a white ^6 porcelain and
519, a white 6^ stoneware.
On PSH 910 only crazing occurred.
On PSH 519 both crazing and shivering occurred sometimes taking a few days
to manifest itself.
Two Recipes: &
================
CUSTER FELDSPAR..... 51.00 45.00
WHITING............. 9.00 8.50
EPK KAOLIN.......... 5.00 4.00
SILICA.............. 23.00 31.50
LITHIUM CARBONATE... 12.00 11.00
======== ========
100.00 100.00
CaO 0.27* 5.82%w 6.31%m 0.28* 5.42%w 5.85%m
Li2O 0.49* 5.49%w 11.21%m 0.49* 4.98%w 10.11%m
MgO 0.00* 0.03%w 0.05%m 0.00* 0.03%w 0.04%m
K2O 0.16* 5.87%w 3.79%m 0.16* 5.12%w 3.29%m
Na2O 0.07* 1.75%w 1.72%m 0.07* 1.53%w 1.49%m
Fe2O3 0.00 0.16%w 0.06%m 0.00 0.14%w 0.05%m
TIO2 0.00 0.02%w 0.01%m 0.00 0.01%w 0.01%m
AL2O3 0.31 12.10%w 7.21%m 0.30 10.40%w 6.17%m
SiO2 3.02 68.76%w 69.65%m 3.51 72.36%w 72.97%m
P2O5 0.00 0.01%w 0.00%m 0.00 0.01%w 0.00%m
COST/KG 2.88 2.70
Si:Al 9.66 11.83
SiB:Al 9.66 11.83
EXPAN490.89 441.32
MDT: RSE01.TMT
Sorry about adding to the confusion on this but had to get my 2cents worth
in.
Margaret
Ron Roy on mon 7 jan 02
Excellent information Margaret - thank you so much - saves us all from yet
another dead end.
I know there have been other examples on this list of fit problems with
lithium carb - would any of you who have had a "Lithum Carb" glaze
experience please post the glaze and results to me - I am starting a file
and will try to find out what is going on.
It is important to tell me - on what kind of clays the problems occure -
including which were a problem and which not.
It would also be helpful if I had a quick description of the firing cycle.
RR
>A while ago there was a thread on this topic and reference to the glazes
>containing lithium carbonate and zinc. I knew I had experienced this
>phenomenon but did not have access to my test tiles and glaze recipes for a
>while, well here is the recipe that did it for me.
>
>I do not know where the original recipe came from, it was a few years ago
>and I was playing around with and learning how to use Insight, at the time,
>so these are two revisions to the original recipe.
>
>Note they do NOT contain any Zinc, just lots of Lithium Carb......
>
>The glazes were fired to a full cone six with and without additions of
>Chrome ox. 0.25
>Tin 5.0
>
>The glazes were tested on PSH clays 910 which is a white ^6 porcelain and
>519, a white 6^ stoneware.
>
>On PSH 910 only crazing occurred.
>On PSH 519 both crazing and shivering occurred sometimes taking a few days
>to manifest itself.
>
>Two Recipes: &
>================
> CUSTER FELDSPAR..... 51.00 45.00
> WHITING............. 9.00 8.50
> EPK KAOLIN.......... 5.00 4.00
> SILICA.............. 23.00 31.50
> LITHIUM CARBONATE... 12.00 11.00
> ======== ========
> 100.00 100.00
>
> CaO 0.27* 5.82%w 6.31%m 0.28* 5.42%w 5.85%m
> Li2O 0.49* 5.49%w 11.21%m 0.49* 4.98%w 10.11%m
> MgO 0.00* 0.03%w 0.05%m 0.00* 0.03%w 0.04%m
> K2O 0.16* 5.87%w 3.79%m 0.16* 5.12%w 3.29%m
> Na2O 0.07* 1.75%w 1.72%m 0.07* 1.53%w 1.49%m
> Fe2O3 0.00 0.16%w 0.06%m 0.00 0.14%w 0.05%m
> TIO2 0.00 0.02%w 0.01%m 0.00 0.01%w 0.01%m
> AL2O3 0.31 12.10%w 7.21%m 0.30 10.40%w 6.17%m
> SiO2 3.02 68.76%w 69.65%m 3.51 72.36%w 72.97%m
> P2O5 0.00 0.01%w 0.00%m 0.00 0.01%w 0.00%m
>
> COST/KG 2.88 2.70
> Si:Al 9.66 11.83
> SiB:Al 9.66 11.83
> EXPAN490.89 441.32
>
>MDT: RSE01.TMT
>
>Sorry about adding to the confusion on this but had to get my 2cents worth
>in.
>
>Margaret
>
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Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
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