Mr. Huet stated, “…But, after the (Raku) firing of 980 Celsius, I put them right away in a sawdust barrel and leave it for at least one hour. After that I take them out and wait until the right color appears, and fixate it by a plant sprayer with water. If there is not beautiful color to be seen I give a little help with a gas torch!”
Thank you Mr. Huet for permitting me to share.
Given my love for Wood Fired Pottery, learning all that entrails, combined with a soft request for urns… I stumbled on a potter online who uses this glaze on his cremation urn:
After a recent class at the Clayscapes Pottery studio that focused on Alternative Firing methods I was keen on doing some more Raku, specifically Horsehair pieces.
In the process of getting ready to do my own Raku (a service provided by Clayscapes Pottery) I realized my advancement in Raku pottery research actually expanded to more appreciation for glaze recipes as I noted the ‘Copper Matte‘ options (see below):
Here is a run down of my pre-raku items of note:
No thin necks (hard to grasp with the tongs)
No tall slender objects (may fall over easily in the ‘reduction’ phase)
Lids are fired in the kiln separately so this takes up space on the kiln shelf. Note: Andrew from Clayscapes Pottery says he has a method of firing lids so they don’t crack on the shelf – I’ll keep you updated with this helpful hint
Burnishing is fun and meditative (on greenware) & is necessary if applying Terra Sig (for Horsehair prep)
In a 5 gal. bucket put 3 gallons (or roughly 28 pints/28 lbs) of water.
Add 14 lbs. dry clay. Ball Clays works well for white base, RedArt for red.
Add enough sodium silicate, soda ash, Darvan 7, or Calgon to deflocculate (a few tablespoons).
Allow to settle. Overnight is average.
Less plastic red clays such as RedArt or fire clay may require only 6-8 hours, while very plastic clays like XX Sagger or OM4 ball may take up to 48 hours.Terra sig is best when the specific gravity if about 1.14. Useful range is 1.1-1.5. Specific gravity is measured by weighting out 100 gms of water, marking the volume, and weighing the same volume of the sig. Divide the weight of the sig by 100. If too thin evaporate. If too thick allow to settle longer. Apply sig to bone dry greenware making careful not to make too many drips, and buff or Burnish to a nice shine.
Use “patinas” of 1 gerstley borate + 1 colorant as a thin wash over bisqued sigs, applied and rubbed off. Works well on textured areas. Here are some color suggestions added to 1 cup liquid sig: white = + 1 tsp. Zircopax or tin. off white = + 1 tsp. titanium diox. green = + tsp. chrome oxide blue = + tsp. cobalt carb. black = + 1 tsp. black stain purple = + 1 tsp. crocus martis
115 grams Red Art Clay (powder) or Grolleg White Clay
2 cups water
one drop defocculant (darvon or calgon)
*optional we added a small amount of red iron oxide to each recipe for color
Horsehair or Glaze
Horsehair – thicker hair is better. Good to have a friend with horses. Being grateful for this helps add another dimension of “Heartfelt Pottery”.
Glazing the inside – Question: is this feasible? If so, is this solely to help retain liquids? Otherwise I’d think I won’t use interior glaze as the Raku technique produces a porous piece (i.e. not ‘functional’). Most of the pieces I am looking to create are to serve as a storage container for things that don’t need air-tightness or fluid retention. Talking about this with a potential customer is a must!
Copper Matte – ooooh nice, and then sealing
Raku Kiln Firing
Making an adequate number of pieces is important to me – I don’t want to create too little and waste time at the kiln or my money spent renting the kiln firing. I guess making too much isn’t a bad thing as I could always do another firing!
The kiln shelf is 18″ (254.5 square inches), so 1/4 area of the shelf is 9″ x 9″ x ?? – however I think I could fit 2 max 5″ wide pieces w/their lids, in each 1/4 panel area without overcrowding (and without making the maneuvering with the tongs a challenge). The total for the shelf would then be 4 lidded piece + 1 piece without a lid place in the center, for a total of 5 pieces per load. And since the minimum # of load is 2 per firing, then we’re looking at a max of 10.
One way to find out is draw or print out an 18″ circle.
Working with the Raku Kiln firing facilitator about the choreography of us ‘dancing’ around & doing steps so we don’t bump into each other or let a pot not get the horsehair or reduction treatment in a timely temperature fashion.
Scrub Brush to clean pieces after the firing
Clothes: Long sleeved shirt, closed-toe footwear, no polyester clothing
Pan with Sand – to lay horsehair down and roll the piece (if desired)
Combustibles? I don’t know yet if I need to bring my own Sawdust and newspaper, which are popular combustibles
Sealant to help keep the colors from fading, after cleaning pieces