Pottery/Sno Kiln

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Question
My sister and I inherited a Sno Kiln from my Mom (with no manual).  Neither my sister nor I have ever used a kiln before.  It is a Sno kiln, Model P22, Serial 6-79, 2.6 AMPS? and 320 Voltage.  It has a kiln sitter, Model LT-3K. We don't know if the kiln works as it was quite some time that it sat idle at my Mom's prior to her passing.  We would very much like to put it to use again but have no idea where to begin.  Can you please help?

Answer
Dear Jackie,

    Thank you for your recent question. Yes, Sno Industries went out of business many years ago, however, the kiln is a standard kiln so operation of it is easy to use. What you are needing is the manual for the kiln sitter. The LT-3K manual is listed below.

http://www.paragonweb.com/files/manuals/ACF1B.pdf

    Download the manual and read over the instructions for operating the kiln sitter. It is fairly self explanatory, however, I will give you instructions on how to do a dry firing to assure the kiln is operating correctly.

    First, you need to check the kiln elements and make sure they are all connected and in good shape. The elements are the metal wrapped wire that sits inside the kiln brick. The kiln brick is what lines the kiln and is approximately 2" thick and white in color. If the elements are all connected to the kiln and are not broken anywhere, then the kiln should operate correctly.

    Next, check the kiln brick. Because of the age of the kiln, there will probably be some cracks and even some missing pieces of brick along the top edge of the kiln. This is normal due to bumping the kiln brick when loading and unloading the kiln. As long as there are no large pieces missing that leave the metal covering showing from the inside, the kiln will fire correctly.

    Finally, check the kiln base bottom for large cracks. If the bottom has large cracks in it, you can use ordinary sand to fill the cracks and can fire the kiln with no problem. However, if the kiln has large pieces missing, you will need to fix these by patching the kiln. You can purchase kiln patch from Bailey Ceramics at the link below.

http://www.baileypottery.com/kilns/kilnmaterials.htm

    Once you have check the kiln and read through the sitter manual and checked the kiln sitter as recommended in the manual, you are ready to do a dry firing.

    To do a dry firing, you will need the following cones and cone plaque. You can purchase the cones and cone plaque at the following link. Purchase cones 04, 05 and 06 in junior cone size. Be sure they have a zero before the number as these are lower firing cones. Do not purchase cone 4, 5 and 6 as these are high fire. You are just testing the kiln, and do not need to fire beyond cone 04. You will also need a box of Pyro Bar 05 cones for the kiln sitter. Do not use the junior cones in the kiln sitter as they are tapered and will give a false firing maturing temperature. Bar cones are used because they are the same thickness throughout the bar and are easy to place in the cone sitter.

http://www.baileypottery.com/cones/cones1.htm
http://www.baileypottery.com/cones/cones2.htm

    If you are unfamiliar with cones, please read the following information to understand how cones are used and rated.

http://en.wikipedia.org/wiki/Pyrometric_cone

    Now, once you have your cones, it is time to set up the kiln for the dry firing. Load the kiln with kiln furniture so that a shelf is sitting eye level with one of the peep holes. A peep hole is a cut out on the side of the the kiln where you can look inside during firing to see how the kiln ware is doing and to check cones if you use them. It has a cone shaped plug that is replaced to seal the kiln after inspection.

    Kiln furniture are posts (legs) and shelves (tables) used to set pottery ware and cones on and are usually stacked to meet the height of the ware. For instance, if you were firing many pieces, you would begin by placing pieces on the kiln floor, then use kiln posts to create the legs for a shelf to sit on. You would place the shelf on the posts and continue loading your ware on the shelf. You would repeat this process until the kiln was full.

    When you have placed the shelf the same height as a peep hole, place a set of pyrometric cones on the shelf. Place the cone plaque in the center of the shelf and place cone 06, 05 and 04 in the plaque in that order. The plaque should be placed in the center of the shelf with cone 06 to the left and cone 04 to the right when you look inside the kiln from the peep hole. The reason for this placement is so you can see when the kiln is reaching maturing temperature. Cone 06 will bend first, letting you know that the kiln is almost at maturing temperature. Cone 05 will fall next telling you that the kiln has reached maturing temperature and should turn off. If cone 04 bends, it tells you the kiln over fired.

    Once the kiln pack is set, you will want to set the kiln sitter. Using a cone 05 Pyro Bar cone, place the cone according to the instructions in the kiln sitter manual.

    To fire up the kiln, you will need to determine the number of hours it needs to fire. Using the firing chart listed below, an estimate is used to set the hours needed to fire the kiln. The hours are set using the control knob next to the kiln sitter. It should be labeled from 0 to 20, or there about.

http://images.nitrosell.com/store_images/9/2167/customcontent/0/conechartimage.j

    Looking at the cone chart, you will find Self Supporting Cones and Large Cones headings. Use the chart for the Self Supporting Cones. Under the title, there are two divisions, Regular and Iron Free. Use the Regular title. Next is the heating rate, 27, 108 and 270. In most cases, you will use the heating rate of 270 as this is approximately how many degrees F the kiln rises per hour if set to raise on its own. Since this is an older kiln and it does not have any of the fancy temperature controls, we will use the heating rate of 270 for this and subsequent firings.

    On the left are the cones you use to fire the kiln to maturing temperature. Cone selection is determined on the type of clay you purchase and the glaze you use. Since this is a dry fire, we are using Cone 05 as our maturing temperature cone, so you would need to find Cone 05 on the chart and move to the right to the line under 270 F. The maturing temperature of the cone in F. is 1911 degrees F to maturity.

    To determine how many hours you need to set the kiln to, divide 270 into 1911. Your answer is 7.07 hours, rounded is 7 hours. Always add an additional hour to this number as it takes approximately 1 hour to heat the kiln enough for it to rise properly. So, you would set the hour timer to 8.

    Remember, you are using cones and the timer to fire the kiln. When the timer is about to go off, approximately 7 hours and 30 minutes, you can check the cones in the kiln by looking inside the peep hole and see if they are beginning to bend. The timers only purpose is to make sure the kiln stays on long enough for the cones to bend. It is the cones that will ultimately determine when the kiln is turned off. If the cones haven't begun to bend, replace the peep hole cone and check again in 15 minutes. When the left cone or cone 04 begins to bend, you must stay close to the kiln as it only takes 15 minutes for a cone to mature and bend over properly. This is why cone 04 is your most important cone for determining the upcoming maturing temperature cone bend. Once cone 04 bends, count 15 minutes and check the kiln again to assure cone 05 has bent properly. You should then turn off the kiln, even if the timer hasn't gone off. Turning off the kiln is as easy as flipping the sitter lever.

    If the timer goes off and cone 05 has not bent properly, turn the timer back on to 1 and allow it to time down following the instructions above.

    The kiln sitter is suppose to turn the kiln off when cone 05 reaches maturity. This will happen if it is working properly and when cone 05 in the cone pack bends too. It the cone pack 05 bends but the kiln sitter does not turn the kiln off, then you will need to adjust the sitter according to the instructions in the kiln sitter manual.

    Once the kiln turns off, let it set to cool. Do not crack the lid for at least 4 hours. Then you can raise the lid and use the peep hole cones to prop the lid for further cooling. Your goal is to have a cone pack that has properly bent with cone 04 completely, cone 05 with the tip touching the cone pack and cone 06 beginning to bend.

    Once you have completed this set of instructions, if you wish to write me back, I will gladly help you on your first bisque firing, answer questions, or guide you to further instruction. Let me know how the firing goes. My apologies for the timeliness in answering as we had my uncle and aunt pass away within days of each other. Please forgive me for not sending a message to you straight away.

    I hope this helps you. Always at your service.

Ms. Ti Phillips
Earth Stoke 'N Fire Pottery Studio and Artist Retreat
www.earthstokenfire.com

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Ti Phillips

Expertise

Will answer any questions on hand building, wheel, glaze, firing. Speciality questions to include those in glaze calculation and development, firing techniques. Please do not send questions on identifying pottery. Although I would love to add this to my question topics, I have a retreat to run as well as the studio and volunteering on AllExperts, and therefore do not have the available time to research indentification and marks. Thank you for understanding.

Experience

Experience includes 30 years in pottery design and education. Have taught online and studio classes worldwide for the last 20 years. Own a pottery retreat specializing in firing techniques. Have 12 years solid experience in glaze calculation and formulation as well as problem solving in glaze chemistry. I am the first potter in the United States to have developed a complete package of pottery equipment blueprints for a studio. The blueprints include wheels, kilns, studio furniture, wedgeboards, raku kilns, slab rollers, ball mills and studio tools.

Organizations
Alliance of Pottery Artists Worldwide Association

Publications
Ceramic Industry - PPP Wyndstryder Press - Pottery Journal

Education/Credentials
University of Sciences and Art's of Oklahoma, studied under Professor Jaymes Dudding.

Awards and Honors
Potter of the year with APAWA, various awards for showmanship and design.

Past/Present Clients
Available upon request.

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