shelford on thu 1 jan 98
Bear with me, friends - I have FINALLY got my first glaze load through, all
tests. I won't walk you through it all, shelf by shelf (I'm tempted though
- I'm tempted - I've waited so long for this!) My old standbys all still
work with the new water, bless 'em. But I also tried a few new ones (to me)
from clayart, and here are some results:
Tom Buck's food-safe version of "Cream Breaking Red" - just wonderful!
Simple, low key but extremely pleasant, warm lightly speckled tan breaking
to a rich orangey red at the edges, like a very disciplined shino. I am
already planning the breakfast sets...
Gibby's Wild Rose Tenmoku - spectacular! I guess I will have to get this
one tested, unless someone out there has already done so, as to possible
leaching problems, as it is so low on silica for ^6. On the other hand, the
only questionable item in there is lithium, at 10.5%. I note that some
people were having shivering problems with it. But it is so BEAUTIFUL - has
me dancing little jigs at the very sight - I hope we can get around this.
So far (like, hot out of the kiln) it hasn't shivered on me... BTW, Craig
Martell mentioned that this glaze has a very low expansion, but the
expansion number for it in Insight is 8.8, which is higher than most of my
glazes. Does this mean that high expansion has a low number and low
expansion a high number? And if so (dare I ask it) Why?
Randy's Red - good dark mahogany red, but not an interesting surface.
Although the glaze went on a bit thickly, it seemed to fire a bit thin. I
notice Barbara Lewis mentions using half crocus martis and half RIO, instead
of all RIO. I must get some and try it. But mainly, will have to try it
thicker to try to get depth and character.
Deep Purple - described as, when thick, a lovely deep red purple, very
complex. Unfortunately, I just got a not-very-interesting lightish blue.
It may need to be a WHOLE LOT thicker - I shall try again.
Blue Sugar - just renamed this variation of my "Tenmoku Gold" that I posted
to the list some months ago. As I reported earlier, when the Richmond
Potters Club did a whole series of tests with that glaze, one that they came
up with was dark blue with silver flecks. I have now tested it in my own
kiln, using 1.5% cobalt instead of RIO, and got slightly silvery mauve to
purple sugaring in a deep blue glossy base. Very attractive, might be a
useful addition to the perennial call for blues. Best sugaring in crevices
and bowl shapes where it can pool.
Now, all I need to do is get that web-page going, and I can post some
pictures. Of course, if anyone had a free digital camera they'd like to
throw my way, I wouldn't say no...
- Veronica
P.S. I haven't posted the recipes, as they have all recurred on the list ad
nauseum, but if anyone wants them, pop me a note privately.
___________________________________________
Veronica Shelford
e-mail: shelford@island.net
s-mail: P.O. Box 6-15
Thetis Island, BC V0R 2Y0
Tel: (250) 246-1509
Ron Roy on fri 2 jan 98
Hi Veronica,
When calcutating expansion/contration - or measuring it - the higher the
number the more the glaze (or clay) will expand on heating and contract on
cooling.
Keep in mind when discussing expansion (expansion always means expansion &
contraction when we talk about it) - it is never the fault of either the
clay or the glaze - always too much difference between the two.
So how can I, as I often do, say " this glaze is likely to craze on most
bodies"? Well most of the bodies have a similar expansion rate - how do I
know that - I've measured many clay bodies with my didatometer. There is an
exception to that statement - most are similar - above cone 6 we have to be
aware that there can be cristobalite in our clays - that can alter the
expansion a lot.
I would like to try and adjust the Wild Rose glaze - if you are willing to
do some tests. It may be possible to at least reduce the amount of Li2CO3
(a problematic material) and make the fit more predictable. Send me the
recipe if you are agreeable Veronica.
If the glaze is shivering
>Gibby's Wild Rose Tenmoku - spectacular! I guess I will have to get this
>one tested, unless someone out there has already done so, as to possible
>leaching problems, as it is so low on silica for ^6. On the other hand, the
>only questionable item in there is lithium, at 10.5%. I note that some
>people were having shivering problems with it. But it is so BEAUTIFUL - has
>me dancing little jigs at the very sight - I hope we can get around this.
>So far (like, hot out of the kiln) it hasn't shivered on me... BTW, Craig
>Martell mentioned that this glaze has a very low expansion, but the
>expansion number for it in Insight is 8.8, which is higher than most of my
>glazes. Does this mean that high expansion has a low number and low
>expansion a high number? And if so (dare I ask it) Why?
Ron Roy
93 Pegasus Trail
Scarborough,Canada
M1G 3N8
Evenings, call 416 439 2621
Fax, 416 438 7849
Studio: 416-752-7862.
Email ronroy@astral.magic.ca
Home page http://digitalfire.com/education/people/ronroy.htm
Barbara Lewis on sat 3 jan 98
Dear Veronica: Don't bother applying Randy's Red thicker, it will just
become a more dense tan color. But DO get the crocus martis -- YOU WON'T BE
SORRY! An absolutely beautiful color! Best wishes and congratulations on
your results. I enjoyed reading this post. It makes me want to get out
into the studio, that I've neglected for a while. Barbara (where in the
D.C. area it is 62 glorious degrees today!)
At 01:04 PM 1/1/98 EST, you wrote:
>----------------------------Original message----------------------------
>Bear with me, friends - I have FINALLY got my first glaze load through, all
>tests. I won't walk you through it all, shelf by shelf (I'm tempted though
>- I'm tempted - I've waited so long for this!) My old standbys all still
>work with the new water, bless 'em. But I also tried a few new ones (to me)
>from clayart, and here are some results:
>
>Tom Buck's food-safe version of "Cream Breaking Red" - just wonderful!
>Simple, low key but extremely pleasant, warm lightly speckled tan breaking
>to a rich orangey red at the edges, like a very disciplined shino. I am
>already planning the breakfast sets...
>
>Gibby's Wild Rose Tenmoku - spectacular! I guess I will have to get this
>one tested, unless someone out there has already done so, as to possible
>leaching problems, as it is so low on silica for ^6. On the other hand, the
>only questionable item in there is lithium, at 10.5%. I note that some
>people were having shivering problems with it. But it is so BEAUTIFUL - has
>me dancing little jigs at the very sight - I hope we can get around this.
>So far (like, hot out of the kiln) it hasn't shivered on me... BTW, Craig
>Martell mentioned that this glaze has a very low expansion, but the
>expansion number for it in Insight is 8.8, which is higher than most of my
>glazes. Does this mean that high expansion has a low number and low
>expansion a high number? And if so (dare I ask it) Why?
>
>Randy's Red - good dark mahogany red, but not an interesting surface.
>Although the glaze went on a bit thickly, it seemed to fire a bit thin. I
>notice Barbara Lewis mentions using half crocus martis and half RIO, instead
>of all RIO. I must get some and try it. But mainly, will have to try it
>thicker to try to get depth and character.
>
>Deep Purple - described as, when thick, a lovely deep red purple, very
>complex. Unfortunately, I just got a not-very-interesting lightish blue.
>It may need to be a WHOLE LOT thicker - I shall try again.
>
>Blue Sugar - just renamed this variation of my "Tenmoku Gold" that I posted
>to the list some months ago. As I reported earlier, when the Richmond
>Potters Club did a whole series of tests with that glaze, one that they came
>up with was dark blue with silver flecks. I have now tested it in my own
>kiln, using 1.5% cobalt instead of RIO, and got slightly silvery mauve to
>purple sugaring in a deep blue glossy base. Very attractive, might be a
>useful addition to the perennial call for blues. Best sugaring in crevices
>and bowl shapes where it can pool.
>
>Now, all I need to do is get that web-page going, and I can post some
>pictures. Of course, if anyone had a free digital camera they'd like to
>throw my way, I wouldn't say no...
>
>- Veronica
>
>P.S. I haven't posted the recipes, as they have all recurred on the list ad
>nauseum, but if anyone wants them, pop me a note privately.
>___________________________________________
>Veronica Shelford
>e-mail: shelford@island.net
>s-mail: P.O. Box 6-15
> Thetis Island, BC V0R 2Y0
>Tel: (250) 246-1509
>
Barbara Lewis
5412 Well Spring Road
La Plata, MD 20646
blewis@crosslink.net
(301) 932-3915
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