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 “Nouveau Jars,” each 13 in. (33 cm) in height. All are stoneware with kyanite added for thermal shock resistance, with Riggs Terra Sigillata, bisque fired to Cone 07–06, then refired and removed from the kiln at Cone 015 for horsehair application.

March 26, 2007

The Advantages of Horsehair Raku

by Bob Hasselle | Read Comments (20)

Sometimes I think the university system needs to be geared more toward the needs of people in the crafts. After the third or fourth diatribe in art history class on the arcana of various stages of the Cubist styles of Picasso and Braque, it occurred to me that maybe there should be an art history class on the crafts movement. As I see it, the class would start with William Morris (the elder) and the reaction to the Great Exposition of manufactured goods at the Crystal Palace in London. This would lead to the subsequent founding of the English Arts and Crafts Movement, which was the beginning of the modern [Western] interest in crafts. The course would then proceed through Art Nouveau, Frank Lloyd Wright and the Prairie School, the work of Louis Comfort Tiffany, and the American art potteries such as Rookwood and Newcomb. After touching on the California Arts and Craft Movement and Art Deco, the course would end with the work of William Morris (the younger), one of the greatest glass blowers of our time. Morris has been a great inspiration to me in my current horsehair raku line.

I first started this line of work while creating porcelain and redware torsos decorated with tattoos of birds and animals. None of these works had the look that I was after, however. The commercial look of clear glaze over red and white clay seemed to contradict the Neolithic imagery. So, I set them aside for about a year. Later I discovered the horsehair process, which gave them the overall look and surface patina that made them come alive for me.

In my work, I try to combine well-thought-out vessel shapes with very simplified sculptures of birds and animals reduced almost to gesture drawings in three dimensions. These sculptures are often wire cut from a block of clay to approximate dimensions. I then carve away and add clay until I get what I want. The finish can be attained with a hard-paste wax (like Trewax) or sprayed on with polyurethane varnish. This can be tricky, because you don’t want it to run.

One’s choice of media has to do not only with how to do it, but why to do it. All kinds of pit and raku firing appeal to me, but if you want color control and a certain amount of compositional control, the horsehair raku process has its advantages. With this control, you can concentrate on the imagery and not worry whether that copper blush or carbon deposit will occur where you want it to.

Another aspect of the “why to do it” is the creation of a coherent line of work that may start off being derivative but ultimately becomes your own. This process happens more effectively when you pay attention to your personal ideas and where they are leading you, and to the input you are receiving from the medium.

The Horsehair Process

Applying horsehair is not a complicated process. Although I call my pots raku, because it is the category that fits best, they do not require the same level of heat. I take them out of the kiln at 1500°F (815°C) by my pyrometer, which may not be accurate. I remove them when they are starting to glow inside of the pot. It is important to remember that you are not trying to melt glaze, only horsehair. The heat will determine the boldness of the black squiggles left by the horsehair. I like a bold line and darker effect. The hair from the tail of a horse is superior to the mane hair, because it is longer and more coarse.

Another tip for horsehair raku is to put some sawdust or other combustible under the bottom of the pot during firing. The temperature of the bottom of the pot is often not hot enough to ignite material after it comes out of the kiln. To get the brown to orange colors, the pot is sprayed with ferric chloride after the horsehair is applied.

Recipe

I use underglazes for color before the bisque but after applying the terra sigillata. Terra sigillata allows one to polish the vessel to a near reflective surface. I recommend a recipe from Linda and Charlie Riggs. The quality of their work is a great standard to emulate

 

Riggs Terra Sigillata

Water

3-1/2 gallons

Sodium Silicate

1 tbsp.

Soda Ash

1 tbsp.

XX Saggar Clay

6,804 grams

Mix ingredients and wait one day. Siphon off and use only the first 1Z\x gallons.

 

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20 Comments

Add Your Own Comment

Wes | May 23, 2008 1:22 pm

In reference to applying under-glaze slips for color and Terra Sigilatta. Which is applied first? I would think the colored slip is applied first then the TS ? However, there are so many folks saying so many things. Don't apply TS to bisque-ware! Do apply it!....Spray FC on the pot while it's hot!... Brush it on the pot before saggar firing! I would like to know what kind of results you folks are getting with these very different approaches to this wonderful experience. Thanks for sharing.


Paulina | January 23, 2008 6:20 pm

Chiqui. What is 1Z/x gallons of Riggs Terra Sigillata recipe. chiquiburneo@hotmail.com


Cactus Jack | November 12, 2007 9:00 pm

I use the process that Randy Brodnax and Don Ellis showed us up at Sierra Nevada College. They use a PREVAL sprayer. It can be bought at Ace Hardware or at Home Depot. Take care to use safety equipment and don't turn it upside down.


lou | November 12, 2007 8:54 pm

Anyone; what do you spray FC with? Thanks, Sou


leena | October 18, 2007 9:37 am

Thanks, Ben, It is definitely worth a trial, can't wait to do so!


Ben | October 17, 2007 10:39 am

For an interesting effect when using F.C. dilute it with water (50/50 is fine) and use a brush to apply it to the pot. Before you fire, wrap the whole thing in tin foil. Don't worry about getting it smooth--the foil will make interesting patterns in the F.C. When you fire it, you just have to pull the foil off while the pot's still hot and apply horsehair.


Jim | October 16, 2007 10:14 pm

Leena, The post-firing process is usually done by spraying F.C. over a glaze, I've generally used a base white and sprayed whenever I pull the pot. This is done pretty hot, whatever glaze temp. is, so you should have time to do both F.C. and horsehair. Work upwind with the F.C. it's potent and dangerous. Wear a vapor mask if you're worried. Jim Cullen - Roundhouse Pottery


Cactus Jack | October 16, 2007 8:50 pm

Leena: You are right. If you wait long enough to use the horse hair, you run the risk of having waited to long to use Ferric Chloride. If you want to use FC after bisque and prior to the Raku fire, you may want to wrap it up in Aluminum foil. Else, go back to Cobalt Chloride.


leena | October 16, 2007 9:00 am

Jim, I know, applying T.S. to a bisqued pot is a losing game, but my question was about ferric chloride, can it be applied to the bisqued pot before the firing? I never seem to get things right, if it is horse hair first, then the pot is too cold for ferric chl., and the same thing in reverse. I am asking this question, because cobalt chloride wash before firing works wonderfully.


Jim | October 15, 2007 8:43 pm

Leena, I've terra sigged bisqueware and had bad to worse luck. The T.S. has a tendancy to pop-off and leave areas of un-T.S. surfaces. Doesn't make for a very pretty pot. I've tried to buff these areas out and sometimes it works and not too much othertimes. Keep trying, sometimes the next experiment my be the one that sets you apart from the pack. Jim Cullen, Roundhouse Pottery


leena | October 14, 2007 9:38 am

Leena Batra, 14th Sept. While making terra s. I dissolve sodium sil. and soda ash in hot water, because they tend to form very hard bits otherwise. Also I have got a question, can ferric chl. be applied to the pot at any other stage, say, on the bisqed pot befor firing?


ruth | September 16, 2007 9:16 am

Please explain what underglaze colors you use. I understand that you put underglaze on the pot after the terra sig. Does the color come from the underglaze or the ferric chloride or from colored terra sig? RS


Cactus Jack | August 13, 2007 9:55 pm

I use a Preval sprayer to coat the Ferric Chloride with. Try not to get to great an angle on the sprayer or it will freeze up. (Caution: use safety glasses, and a good mask.) The color will change as the piece cools so it is good to experiment. Also you can dilute the FC with water. Don't be afraid that the piece will crack, it has never happened to me.


Bobbie | August 7, 2007 8:08 am

What do you use to spray the ferric chloride on with. I read somewhere that the acid corrodes certain tips on sprayers.


terri | July 9, 2007 1:57 pm

Thank you Jim!


Jim | July 9, 2007 1:40 pm

Terri...I spray the ferric chloride while the pot is hot, hot enough to boil the f.c. BTW, ferric chloride is nasty stuff. Spray out doors and be sure you and others are upwind. You don't want to breathe the fumes!!! Also, the brush you use needs to be washed well and probably won't be used for anything else. Don't use a foam brush, it will melt. Ferric Chloride is available at Radio Shack. It's called Etchant Solution. Hope this helps. Jim Cullen


Jim | July 9, 2007 1:39 pm

Kurt... that's 1-1/2 gallons. Charlie Riggs suggests you throw the rest away. I'm doing some tests on the second gallon. Jim Cullen Roundhouse Pottery Campobello, SC roundhousepots@bellsouth.net


terri | July 6, 2007 6:42 pm

Um, I have question too... to get the orange/brown coloring on the horsehair pot,do you wait until the pot is cool to spray it with ferric chloride, or do it while it's still hot? I've never done anything like this and I'm thinking that the pot should probably cool first so it won't crack etc...... but what do I know! Thanks


Kurt | July 3, 2007 10:48 am

Just exactly what is "1Z\x gallons" in the last line of the Riggs Terra Sigillata recipe. Kurt Wild kurtwild@sbcglobal.net


Kurt | July 3, 2007 10:47 am

Just exactly what is "1Z\x gallons" in the last line of the Riggs Terra Sigillata recipe.