Saggar Firing is the method of creating confined atmospheres within a container or saggar. The saggar can be made out of anything depending on the type of firing from the traditional refractory clay to newspaper. Originally saggars were used to protect the finish from the debris flying around the firing chamber from the wood or coal fuel source. Roughly 200 years ago, potters decided to reverse this and use the saggars to hold material near the pieces to dramatically change the finish.
Up in Smoke Pottery currently uses 3 different materials for their saggars; aluminum foil, tin cans, and paper grocery sacks. Here is a little about each.
For the aluminum foil saggars, we thoroughly coat the bisque terra sigg’d piece with Ferric Chloride. Ferric Chloride is comprised of Hydrochloric Acid and is used for many purposes including metal etching. Proper protection should be worn when using Ferric Chloride including rubber gloves, apron, and a respirator. Fumes from heated Ferric Chloride can be hazardous to your health. The Ferric Chloride can be brushed, dipped, poured, sponged, or whatever you feel most comfortable with. We typically do 1-2 coats, but we are real scientific in our application. We are looking for even saturation of the chemical on the piece. Remember at this point fingerprints and other markings will be permanent. So wear gloves! You can sprinkle on salt, sugar or other powders for effects. The powder will stick to the piece while it is wet. WARNING! AVOID METALS AND METAL OXIDES. The combination of the metal and the acid will produce a gas that may be hazardous to your health.
The piece is set aside to dry on several layers of newspaper or other disposable absorbent material. We then drape horsehair or sisal twine over the piece to create the contrasting black areas. The piece is then wrapped in crumpled aluminum foil and sealed tightly. We use anywhere between 1-3 layers depending on the piece and the look we are going for.
We typically fire these saggars in a raku kiln, but can be done in an electric or a pit. We pack the kiln with pieces ensuring there is airflow around each piece. We fire until the foil loses its sheen, its shine. We really only watch the temperature to make sure we don’t go over 1350 degrees F. We go entirely on sight.
We also utilize paper bags for saggars. We coat a bisque terra sigg’d pot with a diluted Ferric Chloride and place it inside the bag with straw and colorants such as copper and salt. The bag is crumpled down and wrapped in slip covered newsprint creating a large slimy cocoon with at least 5 layers of newspaper. This slippery saggar is placed in a pit fire or often we will fire a barrel full of them at a time.
The final Saggar we use is a tin saggar made from old popcorn tins. We use these for our Blackware finish. Your kiln must be in a well ventilated area to do these saggars. We 1st fire the empty tins to cone 018 remove the paint, sealers and any stickers. Once the tin as been cleaned we place the bisque terra sigg’d piece inside with sawdust, leaves, very small wood scraps, and red iron oxide. Put the lid back on and place in the kiln, we will fire it slow to cone 018 and let cool.