AGATEWARE - NERIAGE - NERIKOMI

WORKING WITH LAMINATED and 

COLORED CLAYS

Agateware - Neriage - Nerikomi

UNDER CONSTRUCTION!

MANY THINGS GOT IN THE WAY THIS WEEK SO I COULDN'T GET THIS ONE FINISHED. IT WILL PROBABLY BE READY IN A FEW DAYS.

When I look at the images and info that I have, this Blog Subject area will be several postings. 

Since spring here is already bursting at the seams, there will also likely be some garden visuals.

WITH ANY LUCK, IT SHOULD BE WORTH THE WAIT!

 

THANKS FOR YOUR PATIENCE!

OUT OF THE SNOWBELT!

VISITOR FROM THE EAST

I WAS SO INTENT ON GETTING THE LAST POSTING DONE, THAT I HAD FORGOTTEN THAT  MY OLDER DAUGHTER KAREN WAS COMING TO VISIT FOR THE WEEK OF  SPRING BREAK. SO I DIDN'T GET THE PLANNED "AGATEWARE" POSTING DONE. SINCE KAREN WAS COMING TO SOUTHERN VANCOUVER ISLAND TO AVOID THE HIGH SNOW CONCENTRATION BACK EAST IN ONTARIO AND SEE SOME OF WHAT IS IN BLOOM IN OUR BALMY. PACIFIC NORTHWEST. FOR THOSE OF YOU CURRENTLY MISSING THE SPRING I THOUGHT I WOULD SHOW YOU WHAT IS IN BLOOM TODAY.

CAMELLIA JAPONICA

COTONEASTER LACTAEUS

CORYLUS CONTORTA - SIR HARRY LAUDER'S WALKING STICK TREE

IRIS UNGUIICULARIS - ALGERIAN IRIS

RHODODENDRON  -  PINK DIAMOND

GUNNERA Manicata

PULMONARIA - Spilt Milk

DAFFODILS,  SKIMMIA,  JAPANESE HOLLY and VIOLA Labradorica

EUPHORBIA Variegata

HELLEBORUS  Orientalis

HELLEBORUS  Orientalis - Prince Igor

MAHONIA Japonica - SWEET CHARITY with VARIEGATED BAMBOO 

THIS IS JUST A LITTLE TASTER OF SPRING IN THE PACIFIC NORTHWEST. AS A GARDENER, THIS AREA OFFERS THE WIDEST RANGE OF PLANTS THAT IS POSSIBLE TO GROW IN NORTH AMERICA.

THE GARDEN IS ONE OF MY MAIN SOURCES OF IDEAS FOR BOTH FORM AND COLOR AS WELL AS DECORATION PROCESSES.

THE NEXT POSTING WILL BE ABOUT COLORED CLAY PROCESSES, AGATEWARE AND NERIAGE. IF I DON'T GET TOO MANY INTERRUPTIONS IT SHOULD APPEAR ON MONDAY, 25TH MARCH. IF NOT, I WILL SEND MORE SPRINGTIME IMAGES

PHOTOGRAPHS BY KAREN KEHLER  OF KARING KARDS
 Website: www.karingkards.com

AND ROBIN HOPPER
Website: www.chosinpottery.ca

BEST WISHES
ROBIN

MOCHA DIFFUSIONS

MOCHAWARE AND MOCHA DIFFUSIONS

DENDRITIC LIMESTONE WITH TREE OR FERN-LIKE PATTERNS (DENDRITES) NATURALLY OCCURRING THROUGH ACIDIC SOLUTIONS PLUS NATURAL PIGMENTS LIKE IRON, MANGANESE SEEPING THEIR WAY INTO SEDIMENTARY ALKALINE ROCK STRATA. IT MIGHT TAKE HUNDREDS OF YEARS FOR THIS TO HAPPEN IN NATURE. IN HARDER, METAMORPHIC, ROCK FORMS THESE DENDRITIC FORMATIONS BECOME THE GEMSTONE CALLED MOSS AGATE.

MOCHAWARE IMITATES THIS PHENOMENON IN A MATTER OF SECONDS BY USING THE PRINCIPLE OF ACID-ALKALI REACTION. 

EARLY 19TH CENTURY ENGLISH MOCHAWARE FROM THE REGION OF CORNWALL. TRAILED AND BANDED WITH MANGANESE DIFFUSIONS ON WHITE SLIP, 

 OR LIQUIFIED WHITE CLAY. BLACK TRAILING IS DONE WITH A MANGANESE AND RED CLAY SLIP - EARTHENWARE

I GET INSPIRED BY HISTORICAL WORK, ADAPT TO MY OWN FORM CONCEPTS AND INTERPRET THE IDEAS ACCORDINGLY. I THEN HOPE TO COME UP WITH PURELY PERSONAL OBJECTS. THE FORMS ARE MAINLY LIMITED TO VARIATIONS ON GEOMETRY, CIRCLES, OVALS, PARABOLAS, SQUARES AND RECTANGLES.

THE WAY THAT I WORK IS TO FIRST FIND OUT ALL THAT I CAN ABOUT THE PROCESS AND ITS GEOLOGICAL ASSOCIATIONS. I THEN DECIDE WHAT COLORS OF SLIP AND DIFFUSIONS I WANT TO WORK WITH AND TEST THEM UNTIL I HAVE WHAT I WANT. THE OBJECTS ARE THEN MADE  AND WHEN LEATHER HARD THE SLIP WORK AND DIFFUSIONS ARE DONE. WITH PRACTICE, ONE CAN MAKE DIFFUSIONS THAT EITHER LOOK LIKE ONE TREE OR A WHOLE LANDSCAPE. SINCE I USE HIGH-FIRED VITREOUS PORCELAIN, IT IS NOT NECESSARY TO GLAZE THE SURFACE.

RH- PORCELAIN DISC FORM - IRON AND MANGANESE MOCHA DIFFUSIONS WITH RUTILE AND WHITE SLIPS - UNGLAZED EXTERIOR - GLAZED INTERIOR
GAS FIRED REDUCTION TO CONE 10

RH - FOOTED PARABOLIC BOTTLE

PORCELAIN WITH RUTILE COLORED  AND WHITE SLIP

DIFFUSIONS WITH MANGANESE AND YELLOW STAINS.

 UNGLAZED EXTERIOR,GLAZED INTERIOR -  GAS FIRED IN REDUCTION AT CONE 10

RH - FOOTED VASE
BLACK COLORED PORCELAIN WITH RUTILE AND WHITE SLIPS
MANGANESE DIFFUSIONS - FIRED IN OXIDATION AT CONE 8

          MOCHA DIFFUSIONS is a little known technique of surface decoration developed and used in the Southwest of England, and subsequently brought to parts of Eastern North America, particularly Canada by itinerant, immigrant, European potters.  It was only done on wares of a simple functional nature, and on forms that were simple in shape, such as mugs, bowl, jugs, chamber pots, etc. The name has nothing to do with coffee, but is derived from the word MECCA, the centre of the Muslium world, in Saudi Arabia.  It is from here that the finest Moss Agate gemstones come.  These gemstones show the veined patterns reminiscent of trees or ferns.  The slow evolution by which these are formed in nature is called Dendritic Formation, where acidic solutions, usually colored with manganese or iron, have permeated between layers of alkaline sedimentary rock.  Compression and geothermal heating has hardened the stone into a gem quality.  In nature these patterns may take hundreds of years to develop.  

In ceramics, the process is done in seconds.  It is quite a simple process but demands exact timing and viscosity control.  As with the natural occurrences, it depends on a reaction between acid and alkali.  It has to be done on wet to leather hard clay – I prefer leather hard -  that hasn’t started to change color in drying.  The timing refers to the state of dryness that exists.  If the pot is too dry, it might well crack or split; too wet, and it might sag or slump.  The viscosity refers to the thickness of the slip coating which is used - too thick and the acid/color mix will not move, too thin and it will run excessively and become blurred.  With experience it is quite easy to control.

SUITABLE CLAYS 

MOCHA DIFFUSIONS was traditionally done on both red and white earthenware, but may be done on almost any clay body at almost any temperature.  Clays that have a high degree of sand, grog or lignite in them are sometimes prone to cracking.  From my experience, a smooth clay body with a high degree of Ball Clay or Plastic Kaolin such as Edgar Plastic Kaolin is the most ideal. All clays and slips are primarily alkaline, a basic necessity for the reaction to take place with the acidic Mocha  “tea” or vinegar mix.

SUITABLE SLIPS

Various slip recipes are good, the most important ingredient being a high percentage of ball clay.  A basic recipe which will fit most bodies and which can easily be colored with stains or various oxides would be;  BALL CLAY 75, KAOLIN 10, SILICA 10, FELDSPAR 5. I have taught this process all over the world and you can use any ball clay, any feldspar, any kaolin and any 200 mesh silica, flint or quartz.  They will all work. This slip is good on most clay bodies from cone 04 to 12,  in any atmosphere. The thickness should be like double cream, or room temperature 10 W 30 motor oil. A liquified porcelain clay slip will not usually work well since a porcelain body usually contains a maximum of 50% plastic clay material, the remainder being non-plastic fluxes and fillers such as feldspars and silica.

ACID/COLOR MIXTURE

The mixture that is used to form the patterns is called “Mocha Tea”.  It was originally made by boiling tobacco leaves and forming a thick sludge that was then thinned with water, and mixed with color to apply.  It probably originated by pottery decorators chewing tobacco while they worked, and spitting in the paint pot, creating a murky brew.  However, nicotine solutions are only a form of mild acid, and any form of mild acid will work, such as citric acid, lemon juice, urine, coffee, or vinegar, particularly natural apple-cider vinegar, which is what I always use.  The mix is made by making a solution of acid, mixed with colorant.  Most colorants work quite well, although carbonates or stains are usually better than oxides, since they are usually a physically lighter precipitate than oxides. Heavy materials such as black copper oxide, black cobalt oxide and red  iron oxide  do not work well, since the acid can’t adequately hold the color in suspension. If you want to use iron, either use black Iron oxide or yellow ocher. If the colorant is gritty the grit will sink to the bottom of the mix and impede movement. A ratio of about 1 heaping teaspoon of color to a quarter cup of mild acid is usually a good starting point.  However, a good deal of individual testing has to be done to get the two liquids to work together to create significant dendritic formations or diffusions, and to make things to work correctly.

METHOD

The leather hard pot is dipped, brushed or poured with slip.  While the surface is still wet, and before it has begun to lose its shine, the acid/color mix is dripped or trailed into it.   It is best done using a well-loaded brush held just touching the slip.  If the viscosity of the slip, and the acid/color mix is right then the feathering pattern will take place quite naturally, as the acid eats a fern-like pathway through the slip pulling the colorant with it.  Traditionally, the surface is coated with a thin coat of clear glaze, or clear, colored glaze, but this might cause the color to bleed out or become absorbed into the glaze, particularly at temperatures above cone 4.  I prefer to use the technique on high-fired wares that do not need to be glazed, and have been doing it that way for over 50 years.  It is a technique that usually takes a while to get used to, but can give interesting results when used sensitively.  It can also be done quite easily on once-fired glazes, providing that they have enough ball clay in them.
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IF ALL GOES ACCORDING TO PLAN, THE NEXT POSTING WILL BE ON MONDAY, 18TH MARCH, 2013.

THE TOPIC WILL BE AGATEWARE AND ITS VARIABLES 

HAPPY READING AND PLAYFUL POTTING! 

COMING UP NEXT!

AMAZING WHAT A LITTLE THREAT

 CAN ACCOMPLISH!

ROBIN HOPPER - PHOTO BY CAT RUSSELL

MANY THANKS TO ALL THOSE READERS WHO SENT COMMENTS  TO MY LAST POSTING.  THE NET RESULT IS THAT I HAVE DROPPED THE "MAYBE" IN FAVOUR (FAVOR) OF "DEFINITELY" IN RELATION TO CONTINUING MY BLOG. TRUTH IS THAT I HAVE ALWAYS BEEN A TEACHER. HAVING TO QUIT WORKING AND TEACHING BECAUSE OF HEALTH PROBLEMS HAS BEEN A REAL BUMMER, AS I STILL HAVE A LOT OF MATERIAL THAT I WANT TO SHARE. I DON'T HAVE THE ENERGY OR STAMINA TO WRITE ANOTHER BOOK, SO THE BLOG  IS MY BEST REMAINING AVENUE FOR BENDING MINDS AND FILLING GAPS IN KNOWLEDGE. I WILL ALSO BE ENLISTING HELP FROM OTHER EDUCATIONAL SPECIALSTS TO LIGHTEN MY LOAD.

ONE AREA OF MY STUDIO WORK FOR ABOUT 50 YEARS HAS BEEN A LITTLE KNOWN SLIPWARE PROCESS CALLED "MOCHA DIFFUSIONS". I HAVE WRITTEN ABOUT IT IN BOOKS AND MAGAZINES AND DEMONSTRATED IT IN VIDEO FORMAT AND WORKSHOPS OVER A LARGE PART OF THE WORLD. I STILL GET A LOT OF PEOPLE ASKING ABOUT IT, SO THIS POSTING WILL HOPEFULLY BE SOMEWHERE I CAN FORWARD QUESTIONERS TO. 

TRADITIONALLY IT IS AN EARTHENWARE PROCESS BUT CAN EASILY ADAPTED TO WORKING AT ANY ATMOSPHERE AND IN ANY TYPE OF FIRING. IT IS AN EASY DECORATIVE PROCESS TO DO BUT TIMING AND VISCOSITY ARE THE ESSENCE. 

PROCESS IS WHAT IS BEING DONE, TECHNIQUE IS THE DEGREE OF SKILL WITH WHICH IT IS BEING DONE.

THE NEXT POSTING WILL BE UP AND RUNNING  FIRST THING ON MONDAY, 11 MARCH. I HOPE YOU ENJOY IT. AS  ALWAYS COMMENTS ARE APPRECIATED.

THE STORY OF MOCHA WARE AND MOCHA DIFFUSIONS

Back in the Saddle again! MAYBE!

HOWDY FOLKS!

I'VE HAD A COUPLE OF MONTHS OFF FROM MY BLOG POSTINGS FOR HEALTH REASONS, BUT I'M THINKING OF LAUNCHING OFF AGAIN BECAUSE OF THE MANY PEOPLE WHO HAVE CONTACTED ME ABOUT CONTINUING IN A CHANGED FORMAT. I DON'T HAVE THE TIME OR ENERGY TO POST AS I DID FOR MOST OF LAST YEAR. MY THOUGHTS ARE AS FOLLOWS:

STARTING NEXT WEEK, I PLAN TO DO A WEEKLY, MUCH SHORTER POSTING TITLED 

"POTS AND PROCESSES"

IT WILL BE LIKE AN EDUCATIONAL SPOTLIGHT ON VARIOUS HISTORICAL POTTERY STYLES AND THE METHODS THAT  BROUGHT THEM INTO EXISTENCE. ONCE IN A WHILE I WILL ALSO INCLUDE DETAILS OF WHAT IS IN FLOWER IN THE GARDEN.

DOES THIS INTEREST YOU? 

IF IT DOES, PLEASE CONTACT ME AND I WILL PROCEED. 

IF I DON'T HEAR FROM READERS, I WILL ASSUME THERE IS NO INTEREST AND PUT MY TIME INTO SOMETHING ELSE. 

BEST WISHES TO ALL MY READERS.

CONGRATULATIONS TO MY IDENTICAL TWIN GRANDDAUGHTERS, ROBYN AND KAYLA, WHO BECAME 21 TODAY. THEY WERE BORN ON THE LAST NIGHT OF NCECA IN PHILADELPHIA. TONIGHT, THEIR BROTHER BEN RECEIVES A GOOD SIZED SCHOLARSHIP FOR HIS EDUCATION IN THE SCIENCES.