View Larger Image “Totem of the Salmon Cult,” 17 in. (43 cm) in height, 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.

November 7, 2007

The Horsehair Process

by Bob Hasselle | Read Comments (0)

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.

HORSEHAIR TIPS
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.

RECIPES
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 the following recipe from Linda and Charlie Riggs. The quality of their work is a great standard to emulate.

Riggs Terra Sigillata
Water...............................................................3.5 gallons
Sodium Silicate......................................................1 tbsp
Soda Ash.................................................................1 tbsp
XX Saggar Clay............................................6804 grams

FOR MORE INFORMATION
To see more of Bob’s work, visit http://www.galleryc.net/robert-hasselle.html. Bob is also featured in our latest handbook, Raku, Pit & Barrel: Firing Techniques, that you can order today from the Bookstore.