Collective Matters

Collective Matters.

CSADceramics 2018

Collective Matters Materion Cyfunol The technical component of a ceramics degree requires that students learn not only how to construct and apply materials but how to source, create and innovate their production.

Ceramics in this way prompts debate about geology, geography, alchemy, science, history, environmental issues, sustainability and all the creative possibilities posed by human endeavor.

From mapping the evolution of Majolica Tin Glaze from Renaissance Florence across Europe to its production as ‘Palissy Ware’ at Mintons, Stoke-on-Trent, to digging and refining local iron rich Terracotta from a local field in Ely, Cardiff, our graduates have studied the ultimate fusion of science and creativity.

They possess an attitude of invention, of flexibility and the commitment to hone the skills necessary to act responsively.

Here are a few of the innovations undertaken as part of the 2018 Ceramics Degree Show.

CSADceramics 2018

Collective Matters Materion Cyfunol

Toni De Jesus:

Lucy Fielden: Marek Liska: Laura Bevan: Morgan Dowdall: Myriam Anwan: Frances Gwilliam :

Adrian Miles: Alina Alglaki: Magdel Strydom : Frances Lukins:

Molochite Additions Ychwanegiadau Molochite Porcelain Fluxes Fflwcs porslen Porcelain Stain Additions Ychwanegiadau Chwenlen Porslen Majolica Application Cais Majolica Tin Glaze and Oxide Tin Glaze ac Ocsid Stain Wash Golchi Syth Crawl Glazes Cwympiau Cribio Colbalt & Transparent Glaze Cobalt a Glaze Trawsglod Mocha Ware Mocha Ware Sand Blasting Relief Rhyddhad Gosod Tywod Dry Glazes Glazes Sych Kulhar: Sustainable Vessels Kulhar: Llongau Cynaliadwy Clay Behavior Ymddygiad Clai

1. Kulhar: Sustainable Magdel Strydom:

In deciding to keep my pots clay, I have the great advantage of reclaiming them to celebrate clay and the coiling process.

“My favourite pot breaking was a lesson to me. A lesson in attachment and my unhealthy need to keep things”.

My desk is an example of how I keep things for oddly sentimental reasons. And I do not want my attachment to my work to keep me from getting excited about what can come after, or how they could be better.

I now look at all the pots I have made for my degree show and look forward to

recycling them. I wonder if I will recycle them in one and have a mixed clay. Or if I will separate the coils as best I can. I am grateful to Andrea from second year giving me the idea to ‘sun fire’ them as she had called it. She just came back from her field trip to India, and while I was confiding in her about not wanting to simply bisque my pots because they loose a surface quality that I enjoy, she told me that maybe I should instead just low fire them.

“Kulhar tea cups are recyclable and deemed sustainable because of this exact firing method. They are set to biodegrade quicker than plastic which is great”.

They are favoured for Chai tea, and are popular because they add an earthy aroma and taste to the tea. And are considered more hygienic. the terracotta that I have fired once to 450 and then reclaimed. This vividly bright orange has such a gorgeous warmth.

The texture between the two terracotta clay bodies is now quite marked. The once fired clay has now become less plastic and a similar type of short to porcelain. But not as smooth in consistency.

I am not sure which components of the original terracotta had fired away, but the the fired clay now even smells different.

Almost like stagnant mud but with metallic undertones, perhaps all the iron in it.

2. Porcelain Stain Additions Lucy Fielden:

“The colours of Cornwall are recorded throughout art history as holding particular warmth and radiance, as being mysteriously heightened by a brilliant quality of light called over from the Atlantic sea”.

It is fascinating how the different levels of sunlight can change our perception, and cause us to experience something familiar as if for the first time.

My use of colour and their composition are inspired by the vibrant boats of Mevagissey, a small fishing village in

Cornwall that has had a profound impression on me from an early age. It is this childhood memory that I try to capture through colour and composition from the varied textures of ropes and nets, to the rusted ladders and plastic fenders.

“This memory of colour, form and composition is re-created through high fired stained porcelain” Its smooth glass-like qualities resembling the boats, whilst the selective bands of high shine glaze reference the glistening surface of the water they float upon.

I used several different stains in my porcelain tests. The method I chose to use in mixing the porcelain and stain or oxide was by making a large indent in a 100g ball of clay putting 8% of

dry stain into the indent, pouring in a little water to mix and slowly wedging the clay until the colour is dispersed fully.

Added to the porcelain are the following stains: Purple stain Grey stain Yellow stain Mild Green stain stain Purple iron oxide Cobalt Oxide

Green stain Coral stain Orange stain Chesnut Brown Iron spangles

The glaze I used on each piece has a firing range of 1240° – 1280° and consists of: – – – – –

38g soda feldspar 14g whiting 12g zinc oxide 6g ball clay 30g flint

Yellow Stain

Green Stain

Iron Spangles

Purple Stain

Cobalt Oxide, marbled cobalt and crank

M ild Green Stain

Grey Stain

Coral Stain

Cobalt oxide, Porcelain and Red onglaze

Orange Stain

Chesnut Brown Stain

Unstained Porcelain

3a Colour Tests in Clay Body Frances Gwilliam:

“This second round of tests examined how mixing stain into the clay body isn’t the only way to include stain.

The colour might look completely different with a layering affect”.

R u tile : cre a te s a ve ry lig h t b ro w n co lo u r w h ich

Iro n S p a n g le s : cre a te a d a rk g re y w h e n m ix

R e d Iro n O x id e + Iro n S p a n g le s : T h is tile

is h e a vily sp e ckle d w ith o th e r d a rke r sh a d e s o f b ro w n . It h a s a so rt o f g ra n ite lo o k to it. A g a in

w ith th e c la y. It is lig h tly sp e ckle d g re y u n g la ze d b u t th e iro n b ro w n sp e c kle s a re

h a s a lig h te r g re y c o lo u r th a n th e p la in iro n sp a n g le s b u t d o e sn ’t se e m to b e a ffe cte d b y

th e co lo u r is a lm o st u n a ffe cte d b y th e g la ze . In th e lin e te st tim e th e b ro w n sh o w s u p a lo t b e tte r th a n th e re d iro n .

b ro u g h t o u t a n d b le e d w h e n g la ze d . In th e lin e te s t tile th e le ft lin e sh o w s u p a n d co n s iste n t b u t a w e a k b ro w n . T h e le ft is d ifficu lt to te ll b e ca u se o f th e sp lit b u t th e c o lo u r se e m s

th e re d iro n . In th e lin e te s t tile th e le ft lin e is w e a k a n d th in b u t th e rig h t lin e h a s a stro n g e r co n s is te n t d a rk g re y c o lo u r.

C o a rs e Illim e n t: cre a te s a lig h t g re y co lo u r in th e cla y b o d y. It is a lso d e n se ly sp e ckle d w ith

stro n g w h e re it’s to g e th e r.

R e d Iro n O x id e + R u tile : T h is tile lo o ks v e ry sim ila r to th e p la in re d iro n o xid e tile b u t

d a rk g re y. W h e n g la ze d th e m a in b o d y co lo u r is u n a ffe cte d b u t th e su rfa ce sp e ckle s b le e d a n d b e co m e g re e n s a n d ye llo w s. It is n o t g o o d o n its

R u tile + C h ro m e O x id e : T h e ch ro m e is le ss d u lle d b y th e ru tile th a n it is b y th e re d iro n .

T h e re a re s o m e s u b tle s p e ck le s fro m th e ru tile

th e re is a slig h t a n d lig h t b ro w n h u e fro m th e ru tile . T h e sp e ckle s th a t w e re in th e p la in ru tile tile a re n o t p re se n t in th is o n e . In th e

T h e se tile s h a d a lin e o f c o lo u r la y e re d in to it.

o w n to p u t in a lin e la ye r b e ca u se th e g ra in is la rg e it d o e sn ’t m ix w ith th e w a te r o r cla y. T h is

b u t m o stly is a n a lm o st b ro w n g re e n . In th e lin e te s t th e co lo u r is m u ch d a rk e r th a n th e b o d y

lin e te st th e co lo u r is a co n s iste n t a n d th ick b u t a w e a k b ro w n c o lo u r.

cre a te s th e sp e ckle e ffe ct in th e cla y b o d y b u t w h e n th in in a lin e it is p a tch y.

te s t w ith n o t ve ry m u ch d iffe re n c e b e tw e e n rig h t a n d le ft lin e s. It is co n s iste n t a n d w o rk s

R u tile + C o a rs e Illim e n t: T h is is a g a in lik e

T h e le ft lin e is w h e re th e p o w d e re d s ta in a n d w a te r a re m ixe d m o re th o ro u g h ly o n to th e cla y b o d y cre a tin g m o re o f s lip , a n d th e rig h t is ju st w a te r a n d p o w d e re d sta in n o t ru b b e d in w h ic h m a ke s a stro n g e r c o lo u r th a n th e le ft.

R e d Iro n O x id e : p la in re d iro n o x id e cre a te s a lig h t g re y , s lig h tly s p e ck le d c o lo u r. T h e sp e ckle s a re b ro u g h t o u t b y th e g la ze b u t o th e rw ise th e co lo u r is u n a ffe c te d . In th e lin e te s t tile th e re d iro n d o e sn ’t re a lly sh o w u p e xce p t a s a slig h t b ro w n co lo u r.

C o b a lt O x id e : cre a te s a ve ry vivid b lu e w h ic h is o n ly b rig h te n e d b y g la zin g . In th e lin e te st th e co lo u r is stro n g o n b o th s id e s a n d th e lin e is th ick.

w e ll in th e lin e la y e rs.

a le s s sp e ckle d p la in c o a rs e illim e n t. In th e lin e te st th is m ix h a s c re a te d a m u ch m o re

sta in th a t is m o st a ffe cte d b y th e re d iro n . It m a ke s th e b rig h t ch ro m e g re e n in to a m o re

R u tile + Iro n S p a n g le s : is m o s t s im ila r to th e ru tile o n e b u t w ith s p e c kle s o f d a rke r c o lo u r

o ra n g e b ro w n w h ich is c o n siste n t a n d th ick th ro u g h o u t.

b ro w n /o live g re e n . In th e lin e te st th e co lo u r is th ick o n b o th sid e a n d th e sa m e b ro w n g re e n a s

w h e re th e iro n sp a n g le s a re . In th e th e lin e te st th e ru tile is a g a in w e a k like th e c o lo u r h a s

C o a rs e Illim e n t + C o b a lt O x id e : T h e m o s t

th e cla y b o d y te st.

b u rn t o u t. C o lo u r is slig h tly b e tte r in th e rig h t lin e , b u t still a w e a k b ro w n .

sp e c kle d co b a lt te st. T h e se b ro w n sp e ck le s d o n ’t re a lly w o rk w e ll w ith th e b lu e . W o rks

R e d Iro n O x id e + C o b a lt O x id e : a d d in g o f re d iro n to co b a lt cre a te s a n ice sp e ckle e ffe ct w h e n

R e d Iro n O x id e + C o a rs e Illim e n t: T h is tile is

b e tte r u n g la z e d . In th e lin e te st th e co a rse illim e n t h a s n o t a ffe c te d th e co b a lts co lo u r a t

g la ze d . T h e b lu e is q u ite n ice ly m u te d b y th e re d iro n . In th e lin e te st th e co lo u r is m u ch m o re th e

a lo t lik e th e p la in c o a rse illim e n t tile w ith le s s sp e c kle s . T h e iro n d o e s n o t m a k e m u ch

a ll. T h is is th e s a m e a s th e p la in co b a lt te st.

d u lle d b lu e th a t I w a n te d th a n in h e b o d y te st.

B o th lin e s a re th ick a n d co n sis te n t.

d iffe re n ce . In th e lin e te st th e le ft lin e h a s a re su lt sim ila r to th e p la in re d iro n , b u t th e rig h t lin e h a s a m u c h th icke r re s u lt b e ca u se o f th e

C h ro m e o x id e : o n its o w n c re a te s a b rig h t g re e n c o lo u r w h ic h is n o t c h a n g e d b y g la zin g . In th e lin e te st th e c o lo u r is ve ry

co a rse illim e n t m ix e d in .

stro n g o n b o th sid e s.

R e d Iro n O x id e + C h ro m e O x id e : is th e o th e r

Red Iron Oxide and Chrome Oxide

Rutile and Coarse Illiment

Iron Spangles and Coarse Illiment

Red Iron Oxide and Cobalt Oxide

Rutile and Chrome Oxide

Iron Spangles and Chrome Oxide

Rutile and Iron Spangles

Rutile and Cobalt Oxide

Coarse Illiment and Cobalt Oxide

3b Mocha Diffusion Frances Gwilliam:

“Mocha Diffusion is a form of slip decoration created by mixing mild acid with stain and dripping it onto wet slip, when done correctly, the stain/acid mix (Mocha ‘tea’) fans out in a dendritic pattern.”

The variables center around the properties and proportions of the two key ingredients acid and stain. For acid, historically tobacco juice was used however, vinegar, urine, turpentine, lemon juice and wine are possibilities. For stain, finely ground stain works best as acid cannot adequately suspend heavy materials.

I made sure that every batch I was testing was done all at once. Testing in one go means a decrease in the difference in variables between each test. If I had waited days between, the slip might be at a different consistency or the clay body tile a bit dryer. Each slight difference would skew the results and make the testing invalid.

I mixed 1ml (a teaspoon) of Malt Vinegar, 1gm (1/4 teaspoon) of stain and Robin Hoppers slip recipe: Slip for Mocha Diffusion Cone 04 – 12 Feldspar 5 Ball Clay 75 Kaolin (China Clay) 10 Silica (Quartz) 10 The importance of the slip in Mocha Diffusion is based on its alkaline nature.

The creation of the dendritic pattern is believed to be a result of the contact point between the ‘tea’ and the slip becoming unstable. This is due to the surface tension of the ‘tea’ being less than that of the slip coupled with the acid/base chemical reaction.

Colbalt: works well as a colourant creating long wide tendrils. From unfired to bisque (1100c) there is very little colour loss.

Red Synthetic Iron: has a low density and mixes well with the acid fanning into tendrils quickly going from dark brown to a deep red brown.

Black Copper Oxide: very dense and difficult for the acid to suspend and defuse.

The tendrils do not travel very far remaining thin also burning out in firing.

Chrom e Oxide: has long and wide tendrils strong colour.

Manganese: Strong tendrils travels well lightening towards edges.

Colbalt Oxide: Vinegar

Colbalt Oxide: Vinegar

Colbalt Oxide: Vinegar

Colbalt Oxide/Manganese: Vinegar

Iron Stain: Orange

Iron Stain: Orange

Colbalt Oxide: Vinegar

Colbalt: Orange

Iron Stain: Vinegar

Colbalt: Orange

3c Colbalt and Transparent Glaze Frances Gwilliam:

“Colbalt acts like flux running with glaze so I tested transparent glazes at different temps to avoid bubbles and enhance the Cobalt marble effect”.

I measured the same amount of water with the dry glaze when mixing each glaze. I dipped every tile once and brushed once across the right hand side of the test tile to test at different thicknesses.

Clear Glaze C1 (Glaze 315, 1250°- 1280°) Feldspar Whiting Barium Carbonate Ball Clay Flint

50 14 3 10 20

This glaze is from The Potters Book of Glaze Recipes by Emanuel Cooper. It glaze didn’t clarify which feldspar to use so I used Potash as a default. The results of this glaze were not satisfactory as the bubbles were still present. In the thicker section it made the marbling underneath almost completely indistinguishable.

Clear Transparent Glaze C2 (Glaze 297, 1250°-1280°) Nepheline Syenite Whiting Talc Zinc Oxide Ball Clay Flint

30 15 5 5 10 35

is the only glaze I tried without any feldspar in it.

It was also the most successful of the tests I did. There was an even coverage of glaze and even in the thicker section there was no bubbling or pitting. This could be because of the lack of feldspar in the glaze.

Runny Transparent C3 (Page 84, cone 8

Stable Transparent C4 (page 34, cone 9-10)

Shiny Transparent C5 (page 85, cone 8)

Soda Feldspar Quarts Calcium Borate Frit Whiting China Clay

Potash Feldspar Flint Whiting China Clay

Potash Feldspar 34 Quarts 23 Calcium Borate Frit 14 China Clay 13 Whiting 11 Dolomite 5

45 17 11 14 5

This glaze was from The Handbook of Glaze Recipes by Linda Bloomfield. It was the second most satisfactory glaze outcome in these tests.

There was very minimal bubbling and it only occurred on the thick side of the tile.

27 32 21 21

This Glaze is also from The Handbook of Glaze Recipes by Linda Bloomfield. It was by far the least satisfactory outcome in these tests.

The glaze almost completely obscures the pattern with its opacity and bubbling.

This glaze is from The Potters Book of Glaze Recipes by Emanuel Cooper. It glaze didn’t clarify which feldspar to use so I used Potash as a default.

The results of this glaze were not satisfactory as the bubbles were still present. In the thicker section it made the marbling underneath almost completely indistinguishable.

Clear Glaze C1

Stable Transparent C4

Clear Transparent Glaze C2

Shiny Transparent C5

Runny Transparent C3

4

Laura Bevan:

Tin Glaze and Oxide

Purple iron is an oxide that can be mixed with water and applied on top of a white tin glaze causing a reaction between the two.

Step one is to mix the tin glaze and remember to sieve it before application. I made a mistake early on by not doing this and the surface had lumps of powder on it when the desired finish is smooth and clean. I now sieve the glaze twice!

Parts dry weight Lead Bisilicate – 60 Calcium Borate – 10 China Clay – 10 Tin Oxide – 10 Flint – 5 Zirconium Silicate – 5

Step two is to apply the purple iron, first mixing the oxide with water and spraying it onto the smooth tin glaze surface. The spray booth is used to apply the oxide as it gives an even finish. The spray booth has valves that can control the water pressure and select a vertical or horizontal spray.

“It is very important that every time the spray booth has been used the spray gun is THOROUGHLY cleaned.”

Contamination of glazes can affect other peoples work. I spent 35 minutes making sure everything was

properly clean before the next person used it.

The first my tests were very smooth with mild crackling, however on one or two pieces the purple iron was breaking off, and so i added a teaspoon of Bentonite to the mix, to get a stronger grip onto the glaze surface.

The first three pots I had spray, the mixture only had 100g of purple iron and 100ml of water so by adding that little extra ingredient I changed the way my glaze looked which helped me understand it a lot more.

5. Majolica Application Marek Liska:

Illustrated books, such as ‘Flora Danica’ from 1753 became an influential force not only in the fields of science and medicine, but art and craft too, where the images ended up decorating porcelain dinner sets for the wealthiest.

“Illustrations of plants from across ages, became great inspiration to me,” for observing interesting forms of growth, as well as colour combination.

I began looking into recording clay growth with similar illustrations, my sketchbook becoming a herbarium.

“In a sense ceramic is another form of herbarium, with deep tradition especially in maiolica” to depict and record plants on the surface of ceramic objects. Particularly medicinal jars, containing powerful natural remedies, whose content was labelled by its in-glaze decoration with pictures or words.

I tried to devise my own in-glaze (Maiolica or Faience), surface decoration process. I wanted to emphasise the rich texture of my hand-build terracotta sculptures, crisscrossed with veins-like imprints of my palm.

“The Tin Glaze allows the Iron rich terracotta undulations to show through the opaqueness, but at the same time, provides a light background for bright colours to flourish”

5. Majolica Application Marek Liska:

Looking for the perfect opaque I tried 10 different transparent or white glazes from various sources, firing each at 1060C and 1160C, as well as their response to opacifiers (either Tin Oxide, Zirconium Silicate, or a combination of them).

All of the glazes were based on High Alkali Frit (or as a replacement to Ferro Frits), Lead Bisilicate, Standard Borax Frit, Calcium Borate Frit, or a combination of them.

They all performed just fine, when the firing was actually good, with only some showing common problems: forming bubbles / foaming, mainly at thicker places, or having uneven, ugly milkiness, or presenting cracks.

“Some had interesting idiosyncrasies, such as Morgan Hall’s Majolica glaze where the the small addition of Lithium Carbonate brought forward bright iron oranges through the white glaze”.

The very simple clear terracotta glaze combining Calcium Borate Frit (65) and Red Clay (35) had a very good fit on terracotta between the temperatures of 1100-1150 C. It produced high gloss bright terracotta, almost honey like, but with greenish tint. However, with the (slightly higher) addition of opacifiers (Tin Oxide 8 and Zirconium Silicate 6), it could only produce murky browns.

From the tests I could combine the best performing transparent base recipe (a combination of mainly Standard Borax Frit and small addition of Calcium Borate Frit), and the best performing opacifier (an equal addition of Tin Oxide and Zirconium Silicate).

My preference was a non-Lead glaze, that can be used on functional ware and can withstand the highest range of terracotta (1150-1170). This allows the clay to reach its fullest maturity – fullest strength and rich, toasty colour.

I’ve put the fired samples under stress test too, soaking them in water for prolonged time and then drying them, either naturally or by the means of a heat gun. I also heated them high with the heat gun and then submerging in cold water, as well as scratching the glazed surface

5. Majolica Application Marek Liska:

with sharp metal objects and then submerging in cold water, as well as scratched the glazed surface with sharp metal objects. I wanted to test the functionality and strength of the glaze, if it would chip too easily or develop cracks.

The samples withstood the stress tests marvellously, possibly because of the addition of Zirconium Silicate as opacifier, which can strengthen a glaze.

However, it’s important to note that the size of the samples were quite small, so tests on larger objects with larger glazed surface area might behave slightly differently, amplifying all forces. colour tests and tests and tests First colour tests. Applying oxides or stains mixed either with just water, water and frit,

or water and transparent base glaze. There was not much difference, so I went with the most recommended version of water andtransparent base glaze, adjusting the ratios as I went along in the research project.

Starting with ratios of 1:1:1 – colouring powders: transparent glaze: water to 1:3:2 and later even more water or glaze as I was adding Rutile by 1/8’s. For faint colour effects, it was easy to thin the colour mixes with a brush and water during decorating, very much like water colours.

“When starting to test inglaze colour additions, the chosen base glaze proved not stiff enough, making brush strokes bleed and finer detail

disappears at the highest range of temperatures (1150-70).”

I tried to adjust the recipe and the mixture of colouring glaze, but at the end I settled with the commercial transparent glaze available in the glaze workshop as the best base, with the addition of the opacifier mix.

The commercial clear glaze provides just the perfect surface and firing range to use flexibly (from 1000-1160C but survives slight over-firing too).

Having the base glaze and colour mixture finalised, I could start looking for materials and mixtures creating a range of colours.

I started with the traditional oxides used to produce a number of colours throughout the history of in-glaze.

Yellows, Marigold to Oranges

Lavender to Purples

5. Majolica Application Marek Liska:

Yellows, Marigold to Oranges

Lavender to Purples

Cactus Greens to Jade Blue

“The search for traditional Naples Yellow was unsuccessful”.

Manganese Oxide is traditionally used to produce plum purples to browns, I didn’t achieve good colour here, perhaps due to a lack of Lead

Green has been traditionally obtained by using Copper Carbonate for more misty, wide spreading, almost metallic greens (G7), as well as Chrome Oxide (G6) for more flat greens. W ith small additions of Cobalt Carbonate I accidentally produced beautiful, deep blue-green (G4), and much lighter shades by adding larger amounts (3/8) of Rutile to Turquoise stain.

I tried various rations of Lead Sesquisilicate or Lead Bisilicate with Antimony but only achieved faint yellows on a bubbly surface. This could be due to the lack of Lead in the opaque glaze with which Antimony usually reacts or just by inconsistency in the ratios.

For oranges I tried mixtures of Vanadium (O4), Rutile (O7), with tiny additions of Cobalt and Chrome oxides, or mixtures of Synthetic Iron Oxide, Titanium Dioxide and Manganese (O9, O9b). None of them were really satisfactory, not even pure Orange stain” for its un-toned bright colour (O6)”.

“The P10 and P10b was the closest I could come to plum purple made up of Manganese Carbonate and small additions of Cobalt Carbonate” W ith 1/8 additions of Rutile the Manganese / Cobalt purple as well purple and lavender stains turned beautiful blue grey, but any larger additions of Rutile turned the samples brown.

For the first time I also tried to add 1/8 of Red Iron Oxide instead of Rutile. As Rutile is an impure version of Iron Oxide, the effect just created slightly orange browns.

“I enjoyed how easy it is to obtain such wide variety of greens, either through combinations of simple oxides or commercial stains”.

cactus greens to jade blue

burgundy to peach pinks

5. Majolica Application Marek Liska:

burgundy to peach pinks

cobalt blue to sky and turquoise

Pink is not traditional to maiolica, but ‘chrome-tint’ pinks are well known in ceramics, so I only needed to add a tip of a brush of Chrome Oxide to the Tin Oxide opaque glaze to create a soft pink (the long finger shape).

Blue is another traditional colour easily obtained by Cobalt Oxide or Carbonate. However,

However, using a stain again, proved more manageable and replicable, with the addition of Rutile producing beautiful peachy pink shades.

“The combination of purple stain and Rutile produced a warmer, reddish colour, close to burnt burgundy, while coral stain didn’t change the colour very much”.

“The Cobalt stain I tested seemed more stable (B9) and more readily adjustable with additions of Rutile. Additions of Synthetic Red Iron Oxide to Cobalt Carbonate produced interesting grey blues (B1)”.

For some turquoises I tried Manganese Oxide and Cobalt (P7), but I could obtain the desirable colours only by using Pink Stain with a little bit of Cobalt Carbonate (P6), or by adjusting Sky Blue or Turquoise stains (they seem exactly the same) with Rutile, turning blue-green with higher additions.

cobalt blue to sky and turquoise

6. Grog Additions Toni de Jesus:

Generally porcelain is not suited for largescale working yet I really like its tactility and whiteness when it reaches its vitrification stage. However, the addition of 7% of fine molochite and/or 1% cellulose fibres should not change the nature of the porcelain but give it more strength.

Working at a large scale magnifies and increases the number of problems associated with strength, shrinkage and crack resistance during making and drying, and with tensions that clay goes through during the firing and cooling stages.

“The addition of grog or molochite opens the structure of the clay body, enabling quicker drying and strength. This reduces its plasticity, so you may have to adapt your usual working methods.�

Once you use it, however, it may become your preferred clay to its greater tolerance levels.

These additions will have high stoneware vitrification points because they almost get in the way of the finer

clay particles when melting and knitting together, which hopefully will prevent my porcelain from warping as much.

I have been experimenting with different grogs from different additions to the actual grinded clay like chrome and different oxides and also additions to molochite. The intention is to hopefully not only use it as a strengthening method but use it as decoration, and with an effect how glaze is affected by that.

In addition, Alina kindly gave a little sample of Carib Sea Moon Sand and I can’t wait for the results!

Toni de Jesus: Porcelain with Grog Additions Porslen gyda Grog Ychwanegiadau

6. Porcelain Fluxes Toni de Jesus:

“Fluxes are added to glaze materials to melt glazes at specific temperatures. Various kinds of fluxes originate from different sources.

Additions of percentages:

Tests on coiled pots:

10% , 30% , 50% of:

1 – 1280°C High Alkaline Frit 50% 2 – 1280°C High Alkaline Frit 50%

Borax Frit Standard, Calcium Borate Frit, High Alkaline Frit

Because of their complex chemical makeup, most fluxes contribute qualities other than melting to the glaze.”

to 3 different temperatures: 1080°C , 1180°C , 1280°C

3 – 1280°C Calcium Borate Frit 10% 4 – 1280°C Borax Frit Standard 30% 5 – 1180°C Borax Frit Standard 30% 6 – 1280°C Borax Frit Standard 50% 7 – 1280°C Borax Frit Standard 50% 8 – 1180°C Calcium Borate Frit 30% 9 – 1180°C Calcium Borate Frit 30% 10 – 1080°C Calcium Borate Frit 30% 11 – 1180°C High Alkaline Frit 50% 12 – 1180°C High Alkaline Frit 50%

1

Toni de Jesus: Fluxes / Fflwiau

4

2

5

3

6

7

Toni de Jesus: Fluxes / Fflwiau

10

8

11

9

12

7. Porcelain Fluxes Morgan Dowdall:

“In marking the skin, part of the point is to set the skin as naught, to treat it, not as the outward part of a living being, but as object.” Steven Connor, Book of Skin.

however the ‘fit’ may cause issues on larger areas. For these reasons I will be using a mixture of Groups C, D & E for my degree show pieces.

Though all groups tested are technically viable and could do the job of implying bruised skin, it’s the small changes between samples that really bring this into reality. The most successful samples are those using the dried coloured clay (Groups C, D & E) utilising a wet surface to bleed the colours together and allowing the colours to not only sit on the surface of the porcelain but to become more integrated in it. It is useful to be aware that the clear glaze can be used as a back up to correct any colour imbalances,

A1 – Stained with strong colours on dry surface A2 – Stained with moderate colour on dry surface A3 – Stained with weak colour on dry surface

Group A – Commercial stains mixed with water. Applied on bisqueware and fired to 1220′

It appears that unless stained with strong colour only blue coloured stains survive the high temperatures. The commercial stains produce strong vibrant colours unless watered down sufficiently.

Group B – Commercial stains mixed with water. Applied after a 1220′ firing and refired to 1040′ B1 = Heated and stained with moderate colour on dry surface B2 = Stained with moderate colour on wet surface B3 = Stained with moderate colour on wet surface Due to the semi-vitrified nature of the porcelain the ceramic now needs to be heated in order for the stains to be absorbed instantly; Fortunately the slow absorption rate allows for the colours to more naturally bleed together during application. The illusion is more succinct than Group A, however certain colours are still too vibrant.

7. Porcelain Fluxes Morgan Dowdall:

Group C – Stains added to a separate clay body, made into watercolour cakes and allowed to dry. A wet brush is then used to lift the colour from the dry blocks.

Applied after a 1220′ firing and re-fired to 1060′ C1 – Stained with moderate colour on wet surface C2 – Stained with moderate colour on wet surface C3 – Stained with moderate colour on wet surface The clay body was successful in toning down the vibrant colours of the stains (perhaps too much so). The balance of blue is still off and in response to the strong blues seen in Group A & B has become too subtle.

Group D – Same technique as Group C. Applied on bisqueware, fired to 1220′ and both re-stained and re-fired to 1040′ D1 – Bisqueware soaked in water before applying colour. A 2nd firing used to balance blues by re-applying reds, pinks and yellows.

D2 – An initial wash of black to emphasise hair impressions, applied on bisqueware and allowed to absorb then washed away and bruise colour applied. 2nd firing reapplying reds, pinks and yellows Balance between colours is much better but yellow is still very subtle. The black wash in D2 was very effective in highlighting the hair impressions. The surface has become slightly ‘dusty’ from the layers of coloured dry clay.

Group E = Various techniques with a final 1060′ earthenware clear glaze firing.

E1 = Fired to 1220′, stained with coloured clay on wet surface and fired 1040′. Final 1060′ glaze firing applied to whole tile.

E2 = An initial wash of black applied on bisqueware, washed away and stained with coloured clay on a wet surface. Fired to 1220′ re-stained to balance colours and fired 1040′. Final 1060′ glaze firing applied to whole tile.

E3 = Fired 1220′, stained with coloured clay on wet surface and fired 1040′.Final 1060′ glaze firing applied only to bruised area.

End results between each sample of the group are all fairly similar. The clear glaze has brought out the yellow and has removed the dusty surface, though I much prefer having the glaze only on the bruised area of the tile.