RAKU Crazy Slip & Crazy Glaze

Crazy Slip:
Fire Clay 40
6-tile Kaolin 30
Fine Grog 20
Custer Feldspar 10
----
100
Crazy Glaze:
Frit 3110 60
Gerstley Borate 40
----
100

This is another technique I learned from Kristin Doner. I've heard a different name for this process, some call it "Naked Raku" This is best described as Reduction stenciling.
This is done by dipping a bisque piece in slip then dipping it again in glaze, then firing it as if it were a crackle glaze raku. After about 10 min in the container, the piece should be taken out and quickly submerge in water. the thermal shock will break of the slip/glaze skin. Slip becomes a barrier between the clay body and the glaze, which prevents the glaze from adhering to the clay body.
Because of the extreme thermal shock of this process, Raku clay should be used.
Also smoother surfaces works better with this technique.

RAKU "Unearthed Glaze"

UNEARTHED GLAZE:
Lithium Carbonate 70
Borax 10
Bentonite 15
Feldspar(custer) 5
___
100
Chrome Oxide 8

I learned about this glaze from another California Ceramic Artist, Kristin Doner
This is a very rustic glaze. It makes pieces look like it was just pulled out of the ocean. This is a low fire raku glaze, and its a great glaze to study a glaze as if fluxes during a firing. Pieces fired with this glaze are taken out of the kiln in the middle of the fluxing process, during the "bubbling" phase. This gives the textured result somewhat resembling craters and barnacles. Lithium Carbonate and Borax react with the change in atmosphere of the raku process. Chrome Oxide in the glaze gives it that green color other colorants can be used for different effects. If left in a raku kiln to cool, this glaze turns into a yellow orange color.

Like most raku glazes, this glaze is not food safe. You should wear gloves when handling this glaze. High percentage of lithium carbonate in this glaze makes this glaze very toxic.

PIT FIRING

These are examples of pots that were fired using a process called pit firing. I've learned of this technique from a California potter/artist, Joe Battiatio. Its a modified version of the way pots were fired by people before people built kilns. They would dig a "Pit" and place their pots in it by stacking them on top of each other. They would then surround the stack with wood and other combustible material then fire it. Joe Battiatio's version, uses sawdust other materials to produce the colors you see. Copper carbonate produces reds and salt produces yellows. And the black is carbon, from the burning sawdust.

JOE'S TECHNIQUE:

-dig a pit

-lay a layer of saw dust at least 3"thick.

-mix copper carbonate & fine table salt in with the sawdust.

-place pieces down

-place cow patties ( dried cow manure) on top of pots.. this is used as a thermal blanket, this burns slower than the wood used to fire this pit. this will help the pieces cool much slower

-wood is placed on top of the stack then fire

Now, I have mixed feelings with this technique and the results it produces. I don't like the black that the sawdust leaves behind and I'm not particularly fond of handling cow poop either. Also, burning a lot of wood and sawdust in the backyard is not so popular with the neighbors. So by dissecting his process and learning what materials does what, I've devised another version that produces results that i want, and won't piss the neighbors off.

Modified backyard version:

materials:

charcoal, steel wire mesh, a few bricks, copper carbonate, salt, seaweed, wood chips, kaolin fiber.

-dig a pit 2 feet deep and wide enough for all your pots. Stacking pots on top of one another produces cool patterns

-lay down a few bricks sideways

-place the steel wire mesh on top of the bricks

-add a layer of charcoal on top of the mesh

-add salt and copper carbonate on top.

-add another layer of charcoal, i like to use the instant light charcoal

-burn and wait till the first layer turns white

-add pots on top and also add sea weed and wood chips (soaked overnight in salt water) around and in between pieces.

-cover with kaolin fiber blanket lid, made from kaolin fiber sandwich between two wire mesh screens

Yes, I know, this version is a little complex but it works. There will be no flames that would attract the local fire department. In the eyes of your neighbors, it will only look and smell like your doing a Polynesian style BBQ. Just put some tiki torches up and wear your grass skirt, to make it look authentic.

RAKU Copper matte

I learned this raku technique from a fellow potter/sculptor, Kathy Mathisen. This glaze is a perfect example of how copper reacts with the change in atmosphere during the raku process. Copper, under complete reduction, turns copper red. When little oxygen is introduced during a process called "burping", copper red turns into a spectrum of other colors. Too much oxygen turns it into a dull green.
Ok now i'm gonna try to explain how tricky this glaze can be. First of all this glaze consist of 80% copper carbonate and 20% frit, the high density of copper in this glaze, gives its richness. and longer "shelf life"(will explain later).. The downside to this glaze is that it is so sensitive to the atmosphere during the raku process. It also requires a few extra steps to get it just right. Unlike most glazes, this glaze should be sprayed on a bone dry
(fingernail thickness) instead of bisque. The reason for this step is to mature the glaze with the piece during a bisque firing.
Why can't the glaze be matured during a Raku firing (cone 06)? This glaze does not need to get to that hot temperature for the copper to react with reduction. In fact the piece will be too hot. The copper will reduce and turn copper red, however if you burp it when the piece is too hot, the heat will not be able to freeze that change in color. The piece will just burn any oxygen you introduce. Now if you do this technique in a "colder" firing, (cone-018) instead of 06 ,almost a 5oo degree difference, the piece won't be hot enough to burn the oxygen.
Why can't I spray the glaze on bisque and then raku fire it @ cone 018? If you don't mature the glaze at cone 06 the frit (glass) in the glaze won't flux(melt) the glaze then would simply flake of the pot and can easily be rubbed off.
This technique actually saves you propane, since you don't have to heat the raku kiln to 06 just to mature the glaze. bisque firing will take care of that.

Ok so you fire this glaze to cone o18. Pull the piece out of the kiln, then placed in a container filled with combustible material, cover quickly. wait a few minutes depending on the piece. you have to let the piece cool a little in the container before re oxidizing(burping)
Form, thickness of the piece, can be a factor . Certain forms, like closed forms hold in heat much longer, there for the time it takes from reduction to re oxidation should be lengthen. Open forms cool much quicker, there fore should be re oxidized much sooner. Same goes with the thickness of the piece. The thicker it is the more time it takes for the piece to reach the proper temperature for re oxidizing. Trial and error. that's the game. Bracketing is one way to achieve success. Start by firing 3 identical pieces. First piece wait, 2 minutes before burping, the next piece, wait 4 minutes, and 6 minutes on the third. wait about half hour before opening the container to completely cool the piece in the container to prevent to much oxidation, this will let the glaze color freeze in place. Then analyze the results

Another downside to this glaze is that it is a temporary glaze. What i mean is that the copper in this glaze will continue to react with the air around it, like a penny or the statue of liberty.
this is the "shelf life" of the glaze. I found that copper matte glazes has a longer shelf life than copper luster glazes. Luster glazes re oxidize in less than a year, while copper matte glazes has about ten years before it completely re oxidizes. I think the higher the density of copper matte glaze (80%) in the glaze makes a difference. Luster glazes usually contain less than 10% copper carbonate.

RAKU crackle

These are examples of raku pottery. This technique shows the beginning potters how a change in atmospheric conditions can affect claybody and glazes. Raku is usually fired at or around cone 06 (1800 degrees F) in a gas kiln, the piece is then pulled out of the kiln and placed in a covered container filled with combustible materials (sawdust, paper or straw).

With this technique, Reduction atmosphere inside the container is produced. Reduction in an atmosphere that lacks oxygen. Unglazed surfaces that are exposed to this reduction turns carbon black. The more porous a surface is the more carbon it tends to absorb. Oxygen is pulled out of the clay surface and burned through this reduction process. The by product in the burning of combustibles is carbon, which is then left behind and trapped in the clay body.

When pots are fired, "heated", like anything, it expands. When pieces are fired with glazes both clay and glaze expand. Since glaze is "glass" and it is the first to be exposed to the difference in temperature, the glaze quickly hardens at its expanded form, while the clay body stays hotter longer, it slowly shrinks. since the clay and glaze are fused, the shrinking claybody pulls the already harden glaze resulting in a crackle effect. Cracking the glaze intentionally by blowing air or spraying a light mist of water exaggerates this effect. When the piece is then reduced, the carbon is absorbed through the cracks where clay body is exposed.

I will post images of the actual technique, step by step, sometime in the next few weeks. I have to make pots for it first. I will also try to explain another type of raku involving copper glazes. Stay tuned!!!

Sake bottles

Sake Bottles

potters of Avanos, in Cappadocia, Turkey

Last September I visited my parents in Turkey. They took me to this place called Cappadocia, in central Turkey, close to Konya. This place is famous for the unique landscape and history. While we were there, we visited a town called Avanos. This place was known for their pottery and carpet production. Potters there get their clay from natural clay deposits at a near by river bank.

The first photo is a clay sculpture placed in the center of the town, it shows the two main crafts this town is known for. The next photo down is a potter doing a demo on a kick wheel. Third photo is a potter using a jig to make a plate, they do this to speed up production and get consistent results. Next photo is a lady doing very intricate & labor intensive decorations on a plate. This last photo was taken on a near by garden, I'm guessing these were the rejected pots. Its great to see similar techniques being used in a small town, in a different country, thousands of miles away.

Sake Set

Pots!Pots!Pots!

-Danielle's Sake set

-Teapot & Raku vase

-Doughnut Teapot(frontview)

-Doughnut Teapot(sideview)

-Pots for upcoming Pit firing

Wood/Salt Kiln

Finished "sumi" Decorated Pots

These are some finished pieces decorated with the sumi brush technique. Insead of ink, I use oxides (usually an iron/copper mix), andhigh fire mason stains and porcelain slip to give contrast with the dark clay body. The third photo is a porcelain body, unglazed and has iron slip with mason stain decoration. The forth is porcelain claybody, with iron decoration and a celadon glaze over it.

sumi brush sketches

I sometimes sketch out pots before i make them. Last year i fell in love with the Japanese sumi brush and ink technique. I love the line weight and tension you can get out of it. Since line gesture is all i seem to think about these days, this technique is something i would love to get more comfortable with.

Surface treatment, and Decoration on pottery compliments form, and form compliments function, To me these are all connected and equally important. Since decorating with oxides on greenware is not easy, practice is necessary. To me practicing brushstrokes on paper helps me "warm up" before i decorate pots. The more comfortable i get with the brush strokes the better the end results seem to turn out.

Martin Luther King jr.

I need some feedback on this drawing.

More Pots!!

Newly thrown pots

Drawing

one night a week me and my fellow caricaturist/illustrators hang out and draw. after a long week of work, this is our way to relax and just draw. This is a great way for people to share new ideas, techniques and get healthy critics from eachother. goodtimes, goodtimes

COMIC RELIEF

ok so let's take a little brake from pots and get some laughs. these are just caricatures I drew at work today, hee hee. Its nice to take a little brake form anything we do and do something a little different. however design is design whether its pottery or caricatures, line, form, gesture..etc. are all equally important.

unfired pieces

These are some new pieces i'm working on. On the last image wood ash is applied on these porcelain pots. they will be fired on wed. Jan 17 in a gas reduction kiln at cone 10 (2380 degrees f)