Raku Class Details

SPRING RAKU CLASS

In this class we will be exploring a range of alternative firing techniques including
carbon trailing, naked raku, and saggar firing, with an emphasis on
experimentation.
Students should make pots ahead of time, with the goal of bringing at least three
bisqued pieces to each of the 6 firing sessions. Try to keep most of your pieces
5X5 inches or smaller. I’ve got two wheels in my studio which we’ll use to make
saggars and, for those so inclined, to throw sodium silicate pots.
To get the most out of the class I strongly recommend that you prepare your pots
in the following way.

1) Pots should be thrown with either Highwater Phoenix or Moon White clay
(available at Mudworks). These can stand up to the stress of raku firing but
also are white and smooth and thus best suited to these processes. I would
suggest staying away from commercially prepared “raku clay”.


2) Glazed pots can be handbuilt or thrown to your preference. If hand
building take special care to create strong bonds at all joints as the stress of
raku firing can cause poorly slipped and scored joints to crack. Wheel
thrown pieces should be well compressed during throwing and walls should
be of even thickness. Thin walled pots can survive raku firing!


3) We are striving for a very smooth, polished surface. Use a metal rib on the
exterior to smooth out throwing lines. Trim when the pot is on the moist
side of leather hard so that you can use the metal rib again to smooth over
trimming lines/marks. When leather hard the pot can be put back on the
wheel and burnished lightly with the back of a silver spoon or smooth
stone.


4) Forms thrown for the alternative techniques do best when they have a
pronounced shoulder. With the Naked Raku method, this shape allows the
slip to adhere better to the pot and produces the most dramatic designs.


5) When the pot is bone dry terra sigillata (recipe below) should be applied in
the following manner: place the pot on the wheel or banding wheel (or
simply brush on if pieces are handbuilt). Using a brush, coat the spinning
pot with terra sig, making two passes. Wait 30 seconds and polish with a
soft cloth. Brush on a second coat of terra sig, making two passes again.
Wait 2 minutes and polish with the cloth.


6) Pots should be bisque fired to cone from 09-010, not the standard 06. We
want to keep the pot porous and a lower bisque temp preserves the shine
from terra sig or burnishing.


TERRA SIGILLATA RECIPE
This is an easy and effective terra sig recipe, compliments of Charlie Riggs.
1) Put 3 ½ gallons of water in a five-gallon bucket.
2) Mix in 1-2 tablespoons of sodium silicate.
3) Thoroughly mix in 9 pounds of OM 4 ball clay.
4) Place the bucket on a table where it won’t be bumped or jostled. Let bucket sit
untouched for 20 hours.
5) Siphon off the top gallon, including the small layer of water that will be on the
surface. Be careful to keep the siphon hose only about ¼ inch below the surface.
6) Discard the remainder.


If you can’t make your own terra sig, please contact me and I’ll provide some.
Classes will be held at my studio at 468 West Third Street, Lexington. I’m in the block
between North Broadway and Jefferson. Plan to wear closed toed shoes. If you have
tongs please bring them. Long thick leather gloves are essential. Smoke and gas from
firing and reduction can be anywhere from irritating to hazardous, so you may want to
invest in a half-mask respirator with cartridges rated for gas/vapor. I just got one online
from Northern Safety and Industrial (Honeywell 7700 series mask) with cartridge for
$50.00. A mask isn’t essential, however.

If you have questions please don’t hesitate to contact me at ascovern@gmail.com. I
know this is a lot of work ahead of time but if you prepare your work well in advance
you’ll have the most fun and get the best results, so I’m happy to walk you through any
problems.

-Al Scovern