Assignment #4, process

Assignment #4: Materials, process, and technique

Although I construct a number of very dissimilar clay forms, I use a central process and technique  for all of them.  The forms include portrait sculpture, large clay jars (and drum bodies), table ware consisting of cups and bowls of various sizes, and Drop spindle whorls (weights).  I have also made stringed ceramic musical instruments,  abstract sculpture, rattles and whistles.  sometimes I utilize  the "pinch pot" method to construct cup bottoms, t-pot parts, or just to amuse myself. 

I generally use Dakota red clay for water jars and drum bodies as it works well in large constructions, fires to a strong bisque finish, accepts stains, and responds well to the smoke fire process.  I also use this clay for portrait sculpture.  Dakota is ideal for a variety of  constructed forms.

I use various high fire porcelain clay bodies for table ware, occasional sculpture, t-pots, and drop spindle whorls.  I have used a number of porcelain clay bodies and continue to experiment with any porcelain I find on the market.  Presently I am using “Kleiber” porcelain.

This quarter I am testing a very dense earthenware clay (JG) supplied by Tacoma Clay Arts.  My experiments with white earthenware clays in the past have not been particularly productive.

 

The similarity that runs throughout my clay forms is that I generally start with clay slabs.  I use the YVCC ceramic shop North Star clay roller.  It will roll a slab of clay 22  X24” and to any practical thickness.  I use (minus four layers of canvas) ½ minus for porcelain table ware and ¾” slabs (also minus four canvas layers) for large jars and drum bodies.  From time to time I will run a batch of thinner porcleain for a run of cups or a batch of thicker Dakota red clay for larger water jars that may need additional structural support.

I always roll a number of clay slabs at one time and let them “cure” for a day or so before using them.  I spray each layer and the separating newspaper and I store them in cafeteria tray containers (top and bottom).  Generally I will run enough slabs to make one jar at a time. I use plastic bags to store the slabs.  These slabs will stay moist and workable for several weeks without any extra precautions. 

I start a “run”  of around 10 porcelain forms by first preparing a list of intended pieces.  Once I approach this number I take the forms to bone dry/bisque kiln ready before starting a new “set” of pieces.  It takes about two weeks per run and I generally finish approximately 40 pieces a quarter including the time it takes to finish individual pieces, apply glaze, help in the firing, and clean up. 

SLAB CONSTRUCDTION.  Working with clay slabs is elementary.  I keep a bottle of suitable slip in a screw-top jar and a brush dedicated to that clay body slip mix.  I seldom score porcelain edges, but always score handles and other fixtures.  Earthenware jars go together much like coil pots, by laying cut, strips of the ¾” clay in layers, joining with slip and scoring, and filling in the final hole with a round slab.  I construct sculpture a layer at a time.

STAINS: I use iron oxide stains for relief with porcelain, applied on textured bisque surfaces and mix an iron oxide slip to treat the surface of Dakota red jars.  I find that black iron oxide works best to bring out surface textures on porcelain but red iron oxide is best for Dakota/earthenware stain.

GLAZES:  I find that the most compatible glazes for my pieces is a combination of two or three shop glazes.  I take great care to pick compatible glazes, clean the edges well, and highlight texture.  I do a lot of test glazing.

I find that burnishing jars is a form of low fired glaze.  The compacting process  of burnishing compacts the surface and offers some further protection. I also find burnishing to be a very compelling finish. 

UNEXPLORED OPTIONS: There are several techniques I’d like to pursue including porcelain surface treatments, green clay lettering, stain finishes, and drum features.  I want to further perfect my spindle whorls so they are more perfectly balanced and easier to produce, and work with sculpture on a broader scale.  Most of all, I’d like to improve my finished glaze patterns and results.

Here is an example of a sculpture made from clay slabs in the "coil method", using strips or rolled clay.  This piece is porcelain, very light, probably holds water if turned upside down.  I like the way these sculptures develop, much like rolling on bandages over  imagination. 

I occasionally use the "pinch pot" method of construction cup bottoms, t-pot parts, or sculpture.  I'll post a "pinch pot" blog in a few weeks/mh