Naked Raku
Bill Crumbleholme has been experimenting with the technique known as "Naked Raku". This involves a lot of work compared to most methods, but
the results can be stunning....
The pots are thrown, burnished by rubbing with a metal spoon, coated several times with a very fine and white "Terra Sigilatta" ball clay slip, biscuit fired, then coated with a slip made of flint and china clay and then a layer of glaze made of high alkaline frit with china clay and a bit of bentonite.
They are fired in the gas fired Raku kiln to 850C and then removed and cooled in a container with sawdust shavings, which burn and provide smoke to etch into the cracks that appear in the slip/glaze layer.
They are sometimes sprayed with water to encourage the the slip/glaze layer to"pop-off" to reveal the original burnished surface of the pot, now traced with lines and spots. Sometimes that layer has to be scraped with a plastic card to remove it, sometimes it has to be ground away with a grind stone.
After cleaning and scrubbing it is washed and dried, then the shine is restored with beeswax polish.
The failure rate is rather high, as there are so many variables involved, thicknesses, temperatures, timings...
but sometimes the results are rather special and cannot be obtained in any other way!
The first few images and a video are some vases and eggs, fired in April 2020, then images below tell the story of a session making these pots, Bill and some of his students did in March 2019.
Camera work by Lizzie Watkins (Nee Crumbleholme!)
April 2020
These are the vessels that came out of the firing.
A close up of a slip cast globe, burnished and treated with layers of fine terra sigilata slip.
A vase with a dark crackle.
Slip cast and press moulded egg shapes.
This video shows highlights of the naked raku firing process.
March 2019
Peeking at hot pots in the gas fired kiln, glaze just melting.
Bill lifting the kiln to reveal the hot pots, which are then transfered using long tongs.
Pots removed from kiln into chest with sawdust burning. A little sawdust is sprinkled over the pot to encourage the smoke and to blacken the inside of the pots.
Some pots were put on dustbin lids and then covered with industrial size cans.
Pam spraying water to make the glaze pop off.
The glaze cools and shrinks when sprayed and so falls off more easily.
The sawdust burns when the hot pots are placed on it, and more is sprinkled over the tops.
The pots pick up the smoke, but only through the cracks in the slip/glaze layer.
A can on top of the pot traps the smoke and slows down the cooling.
The can is removed and the pot sprayed, then the can is replaced.
The glaze pops off to reveal the slip underneath.
Sometimes the glaze is stuck on more and takes a bit more effort to remove.
Sometimes the glazes falls off easily.
Jo spraying.
Another pot burning
The pots placed in the chest tend to burn more and turn darker, with more smoke creeping through the cracks.
Jo spraying another pot, that has been more heavily smoked, by adding more sawdust.
Bill scrubbing a pot to remove the clay slip.
The inside of Bill's dish
The outside of Bill's dish. The slip and the glaze were painted on in radial lines, which might have encouraged the cracks to follow that pattern.
One of Jo's pots, partly cleaned up
A lightly smoked pot popping its glaze.
One of Bill's globes, cleaned up.
One of Jo's cleaned up.
3 of Bill's smaller vases.
3 more
Bill's soft focus crazy pot!
Another of Bill's globes. The spots are caused by air bubbles in the slip/glaze layer.