Still got a long way to go to find nice Iron yellow glazes

This is a line blend of DeBoos high Calcium Matt which goes from red to yellow.
I added Titanium Oxide up to 4% to see what sort of reaction I would get.I also overglazed it with a White rutile glaze of unknown ingredients..ie a bucket of slops :-)

My favourites from this Triaxial

An example of the recipes,the base glaze stays the same and the colourants vary from Cobalt 1.00 to 1.40% and Rutile 5.20 to 6.00% for the nicer greens.The blues are also good but I have been interested in green only.

Search for Shiny Cobalt greens

Triaxial T2 Cobalt Green fired in close formation to Cone 10 oxidation



This blend has been designed for colour; my colourants were Rutile and Cobalt.

Generally the surface quality was semi matte to shiny.The trend was that it became more shiny towards corner C which had Cobalt Oxide at 3% and which probably gave some extra fluxing power and more matt towards Rutile in Corner B at 10% which has an opacifying and matting action in larger amounts.In Corner A the glaze was shiny with a combination of Rutile 6% and Cobalt 1%.The glaze had no crazing but has pinholing and pitting throughout the whole test but Tile 5 is not so bad which could be some external factor like position in kiln and the firing or the actual combination of Fluxing power of Cobalt and stiffening action of Titanium.Also this glaze has high levels of Calcium Oxide provided by whiting which could cause bubbling from Co2 so finding a different source might be useful.



The overall pattern of colour was to move from a Pinky Grey at corner B to Dark blue at Corner C and to Green Blue at Corner A. There were some lovely greens around tiles1.58,13 and 18.Which were very similar colour combination. All had a range of Cobalt 1.00 % to 1.40% and Rutile of 5.20% to 6.00%.

It seems that the right combination of rutile and cobalt consistently give Shiny Greens of varying shades when the flux oxides and Alumina and Silica are constant in the right base glaze..


These Glaze tests have been worked out on Matrix..


Matrix software has been designed by Lawrence Ewing my tutor at Dunedin School of Art



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High Street Gallery

An example of my dry glazes

This is my
Helios Pot 2009 about 18 inches tall.
I work with slabs and roll the clay around any suitable form covered with many layers of newspaper.I add the detail from previously made moulds.My glazes are dry calcium matt glazes.Fired to 1285 o C in an electric kiln.

Dedication and Muddle; it gets worse

You got to be dedicated to do this stuff

Me in my glaze room,I am currently working on another triaxial for Shiny Cobalt greens..I am making a triaxial of Tile 2 ( FLUXT CAO_MGO_LIO__#2)and trying to identify whether it is the Ratio of the Colourants that change Cobalt from Blue to green or Titanium changing it from yellow to Green and OR whether it is the glaze base and interchangeable fluxes as shown in previous triaxials.
Here are the 3 corners of the triaxial

The Ceramic Chicken was made by layering thin pieces of textured clay, I made moulds of unusual textures using Latex.

 

High fired stoneware in a gas kiln

High fired stoneware..I wrap large pieces of slabbed clay around cardboard tubes and place on slab of clay and remove cardboard,it helps to have sheets of newspaper on the tube to ease removal and when firm enough remove tube and shape with a damp piece of chamois leather.

Generally with this colour combination of Cobalt/Rutile calcium needs to be present to obtain some Blue otherwise it changes to green or grey with magnesium and lithium present

From Corner C to B is a line blend of Lithium (C) and Magnesium (B)
This line blend contains no Calcium and has the colour has muted pale Blue at Corner B(T16) The colour in this line blend progressive from very opaque Blue grey to some beautiful shinier greys @ tiles17,18 and 19.and onto a shiny green as it interacts as the Lithium increases and the surface deteriorates at Tiles 20 and 21.Lithium seems to be a valuable secondary flux in smaller proportions adding melt and unusual colour but is not so useful in larger amounts.

From Corner A to Corner C is a line blend of Calcium (A) and Lithium (C)
Again Cnr A(Tile 1) is a Shiny Dark blue green and well melted which quickly changes to a lighter blue green variegated glaze when small amounts of lithium are introduced at T3.The tiles still remain shiny and well melted through to Tile 21.Changes to colour and texture are quite obvious along this line blend and Blue changes to apple green at T6 pinholing starts at T6 and progressively starts to melt and move.Lithium is known to produce bubbles in the glaze melt .At Corner C(Tile21) the glaze has shivered due to the small molecule size of Lithium that causes it to be mobile and it migrates to the Alumina and silica of the body and creates an interface of low expansion glass which peels off.Tile 3 is very beautiful and worth pursuing and developing.The others in the Lithium Line blend have lovely colour but the texture and surface are mostly marred by pinholing or shivering

More on Search for shiny Cobalt greens

General Observations of this triaxial Glaze are.
The glaze is a mostly stable and shiny glaze except at 2 corner Tiles A and C where the fluxes of Calcium and Lithium are predominant and Lithium has become fluid. Corner B is Matt. magnesium. The Blue green colour changing from Dark blue at Corner A to Pale blue at Corner B and Aqua green at C.




From Corner A to Corner B is a line blend of Calcium and Magnesium.
At Cnr A where Calcium is predominant the Glaze is very shiny well melted and Dark blue green it has started to move on the back of the tile this line blend progresses towards Cnr B with Magnesium becoming predominant and the surface has become more muted and becomes opaque.caused by the excessive magnesium.This line has no Lithium in its make up but has remained shiny except T16 and has no crazing.Tiles 1-11 are very interesting glaze tests.
My Colourants were Cobalt Carbonate 2.% and Rutile 6%.

Triax CaO_MgO_Li2O Cobalt Green glaze

Triaxial analysis of FLUX Triax CaO_MgO_Li2O Cobalt Green glaze.
Fired to Cone 10 in Oxidation on LF18 white firing Clay

KNO_CaO Fritt Line Blend

This line blend is exchanging KNO for CaO with Tile A with the most Calcium present and Tile B with the most KNO present.
B2O3 is present as is Alumina and Silica at constant levels. This set of tests have yielded some well melted and slightly fluid results.The colour has a definite pattern of being very strong greeny blue at Tile A and changing to an apple green at Tile B where the KNO becomes more dominant.Generally the tiles have remained shiny due to the Boric oxide adding glass to the matrix, and lowering the maturing temp.It may also have an influence
on colour in the background as it acts as a solvent and disperses colour

KNO_LiO2

This Flux combination of Li2O and CaO has interesting colour changes Shiny durable surface..where Calcium is present and as it decreases and the Lithium increases the surface becomes less shiny and the colour becomes a mossy green.and a dull surface.The surface becomes less durable as it increases with the lithium until it finally shivers off the test at tiles 2-A
Tile 6 stands out as being very different and has a beautiful depth of colour and a non crazed durable surface.I would like to test this combination further for my Cobalt green Glaze project.it seems that tile B and six are very different colourwise. Tile B Has Calcium only and turned blue and does not have any lithium in it. Tile 6 has Calcium and some Lithium and it seems that Lithium helps turn cobalt green .of course it still maybe a thickness of application. but it does have exciting connotations.

KNO__ZnO

This flux combination has KNO decreasing and ZnO increasing from A-B.
Generally this combination has produced shiny viscous glazes moving towards a matt opaque surface which has cracked and likely to peel off caused by the excess of Zinc Oxide which has a a low COE..It has also suppressed the Cobalt Carbonate allowing the Rutile to be more active.creating a more yellowish colour moving to a pale green as it has become matt. In the earlier samples the glaze has a very strong durable shiny quality Tile 5 is still shiny but has started to crawl

KNO_SrO Line Blend

This line blend consists of removing Potassium and adding Strontium.This Combination of Flux created a very inconsistent pattern of texture with very rough ,bubbly unpleasant and shiny to smooth and onto dull and matt. Where the surface quality of the tests were smooth the colour was a bright blue, tiles T3-T6 the Tiles A-2 were coarse and variegated showing some bright green Tile &B was a dull matt with a greenish hue. As a dominant flux produces eventually a matt surface. These fluxes combined are both strong fluxes and their combined fluxing power may have caused the rough bubbly surface and as the power of the flux was decreased with the KNO reduction the glaze smoothed out to eventually become matt and colour suppressed.

Line Blend of KNO_MgO

This Line blend consists of Magnesium replacing Potassium and Sodium.Generally the Colour was muted and the surface moved from shiny opaque to very matt and opaque the colour decreased as the magnesium increased There was no Crazing present and the glaze had a thick glutanous and viscous surface. Magnesium has a low fluxing power and as the amount of MgO increased towards tile 7 the glaze melted less and had less tensile strength and started to flake off tiles 6 and 7,Could also be to do with less shrinkage as well as it has a low coefficient of expansion

In search of Shiny Cobalt Titanium Greens

Line blend shows Calcium Oxide replacing Potassium and Sodium (KNO)


with Alumina and Silica remaining constant...
Cobalt Carb 2% and Rutile 6% is added to all tests.Fired to Cone 10 Oxidation.