Friday, March 7, 2008

More Mochaware Pictures!

Mochaware, also known as mocha diffusion, is a difficult technique mastered by very few pottery artists, but the result is beautiful dendrite patterns resembling tree branches, neurons in the brain, and moss agate - mineral deposits of manganese and iron trapped in rock furrows.

First invented in Staffordshire (UK) in the 1780's during the Industrial Revolution, mochaware was mass-produced for the working class people. Although machinery at the time was considered sophisticated, Mochaware technique required a certain amount of human intervention, which thereby increased irregularities in the pieces (e.g. fingerprints and smudges).

Mochaware decoration is achieved by an acid-base reaction and surface tension. Leatherhard pots are dipped into a wet slip (runny clay and water), and a tobacco-based mixture (called "tea") containing tobacco juice and colorant is lightly touched to the slip with a well-loaded brush of tea.

My formulas for slip, tea, and glaze have been optimized with redware clay. Slip viscosity, oxide strength, and glaze recipe are important parameters that need to be optimized.

This mochaware project has been lingering in my studio for about 1 year, and finally I feel comfortable publishing the pictures. I have saved a lot of my first pots in the process, and plan to post them at a different blog address: http://mochaware.blogspot.com/. This will enable me to delineate my stoneware clay projects from my mochaware project. Please check both blog sites often, I update often - so hit reload constantly.

I will not comment on every picture below, but I thought one description would apply to most. The following picture is of a Mochaware vase with dendritic patterns in the middle and prominent banding above and below. The slip I use here is white, and I use a transparent glaze over the top and apply it to the whole pot including the handle. Note: Adding handles without slip or adhesive is very difficult and requires careful moisture control so a tight junction is made that'll survive firing.


































Mochaware Pictures

Good morning. A successful firing of my redware this past week. The pots below are decorated in a mochaware technique. I'll discuss this more later, but enjoy the pictures - still trying to master my photography skills, so sorry about a few pictures that may not be the best clarity.


























Sunday, February 10, 2008

Glacial Blue Glaze Pictures, New Test Tiles, and Still Cold in Saint Paul!

Hi Everybody,

Sorry it has been awhile since I've posted here. I've been working seriously! Great days to work too, its been cold outside and with the kiln running it makes the studio nice and toasty. -6 degrees F today with wind chill rated at -40F, ouch!

Fresh work from the kiln:

1. Pitcher - Tenmoku brown base glaze with glacial blue on the top half. 6.5" high.
2. Small/Med. Mixing Bowl: I made two of these. Perfect for mixing up a few eggs if that's your thing in the morning or having a heaping bowl of cereal. 3 1/2" high x 6 1/2" wide.

3. Vase: Wow! I liked how this one turned out. I especially liked that my finger marks from throwing show up underneath the brown glaze, and how the glacial blue glaze stopped almost perfectly half way down the wide belly. 6" high.
4. Creamer or Syrup Pourer: A classic. Perfect for warming up a few helpings of cold syrup from the fridge or impressing your coffee drinking friends with a handmade creamer instead of another store-bought cream carton. 5" high.
The following picture are glaze test preparations. I put about 300g of glaze (3/4#) into the cup, add a bit of water, and dip test tiles I made earlier in the week.
Here was the result.
I like some of them a lot, and others I'm not too fond of. These are my own recipes of colorant combinations, using a base glaze from a book I found in the Saint Paul Library, David Chappell - The Complete Potters Guide (1970's).

5. Vase (Front) : A perfect Valentine's gift? Red base glaze with purposeful (?) black lines. I experimented with this one, using a 10mL syringe I found at a local dollar store. I loaded the syringe up with glaze, and found that it output a very specific stream of glaze. I'll experiment more using this technique again, but not right now. 6 1/4" high.


Here's the back side of the vase.

6. Flanged bowl: Brown base glaze with glacial blue top coat. 3" high x 7 1/2 " wide.

Have a great week everyone! I hope to post more soon.