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Magnolia Mud Research

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About Magnolia Mud Research

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    ceramic chemistry
    kilns

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  1. success means Mission Accomplished.
  2. Chicken Scratch

    The following assumes that the reason for adding 'stuff' to the clay body is for decorative effects: Instead of adding grit to the entire clay body, just make a thick slip or paste using the regular clay body to which the 'chicken scratch' or any other material such as rice, crushed river rocks, metal filings, ... is added. The 'slip/paste' is then used coat the designated surfaces. Application can be by brushing, thin slabs, sprigging, pouring, etc. Compression of the applied layers of 'slip/paste' is recommended to insure adhesion to the substrate. The process allows the one to try various 'additives' to the clay body without having to deal with the forming or maturing of the main substrate of the ware being made. The 'slip/paste' can be applied selectively to areas where needed to create the visual or tactile surfaces of the design. After application of the 'slip/paste' the coating can be carved to produce sgraffito-like contrasts between the coating and the substrate color/texture. Paper resists also can produce surface contrasts. I have used this concept on cone 10 ware with high technical success using various sands, crushed iron nodules, chopped pine needles, sawdust, rice, crushed bisque, coarse fire clays, and garden dirt. The aesthetic success rate is moderate. Some forms are enhanced and others are deteriorated. Some additives I have not tried that might work are: crushed glazed ware, dried glaze lumps from left over glazes or hard pan muck from the bottom of a glaze bucket, crushed glass bottles, raisins, and chicken scratch. The main constraint is that the combustibles should burnout during the bisque step and any meltable components should NOT melt during bisque step. As the ad said 50 years ago: "Try it. You'll like it!" LT
  3. You can make one (of these 'tools') out of a soda straw by carefully cutting a nib in the end of the straw and then adjusting the distance between the two tines. The ease of use of the tool depends on the surface tension of the liquid (ink, slurry, ...) along with the liquid wetting characteristics on the nib and on the surface to which the liquid is being applied. I made a similar tool once using two coffee stirrers separated with card stock and held together with tape. LT
  4. Electric-Propane kiln conversion advice

    Agree with Neil, additional thoughts on burner auto shutdowns when the flame is blown out: When designing and operating a gas fueled kiln think about safety as well as the mechanics of the burners. Keep in mind that propane (C3) is significantly heavier than air (relative density 1.5), and will collect in low pockets and flow downhill. Natural gas (NG) is lighter than air (relative density 0.65) and rises and dissipates upwards. flammable range for NG are about 5-15% volume in air and for propane the range is 2.1-10.1% volume in air. LT
  5. Kiln Over firing

    Keep in mind that an 'empty' kiln fires differently than does a properly loaded kiln. I am using 'empty' to mean only shelves, shelf spacers, and cone packs. LT
  6. Making terra cotta bricks

    Or you can just use several layers of newsprint. The top layers stick to the bricks, the bottom layers stick to the board, and middle layers are free to move and peel away when the bricks are lifted. Cardboard and tarpaper should also work. LT
  7. Glass Transition video

    The ACerS CTT (CeramicTechToday) blog post today opens with a video relevant to glazes and the vitrified portion of mature clay bodies. It provides scientific insights via an entertaining series of analogies. Quote: Video: Glass transition concepts illustrated in humorous video Published on December 20th, 2017 | By: Faye Oney If you’re a glass scientist you understand basic concepts of glass transition, glass relaxation, and crystallization. But if you’re a student studying chemistry, physics, engineering, materials science, or glass and ceramics, initially the concepts may not be as easy to grasp. For the rest of us non-scientists, and especially right-brained people — well, let’s just say that we really do try hard to comprehend glass science concepts! http://ceramics.org/ceramic-tech-today/video-glass-transition-concepts-illustrated-in-humorous-video LT
  8. PQotW: Week 37

    You only need to have read the book LT
  9. Soda Firing Questions

    About 30 (+/-) years ago, alumina beads, similar to what you are describing, were used to remove alkali vapor species from hot gases in research pilot plants developing the technology for the production of syngas from coal and biomass to be power stationary gas turbines. The beads captured the sodium and potassium species as alkali aluminate, a reaction product of the vapor species with the alumina. Much of the work on alumina pellets for alkali vapor removal was done at Argonne National Laboratory. The important point for potters to keep in mind is that porous alumina pellets are very reactive with sodium vapor species in combustion environments at temperatures above about 600 c. The good news is that the reaction product is not a glaze, just a crystalline solid that is soluble in hot water. ANL was issued patents on an alkali vapor analytical probe based on alumina bead technology. LT
  10. Crystalline Glaze Chemstry

    Tom, well done! I am encouraged to see that someone else believes that it is possible to make good crystalline glaze application without the glaze running off the pot! LT
  11. Soda Firing Questions

    While I have no specific recommendations for the choice of refractory for cabako's kiln, I do want to comment on where to look for insights. The interior of a black liquor furnace (a industrial device used in the manufacture of paper) is exposed to similar refractory corrodents as found in a salt/soda pottery kiln. Anyone seriously studying deterioration of a soda/salt kiln should not ignore the understandings of refractory corrosion that have been published in the black liquor furnace literature. I recall reading a late 1990's paper on refractory corrosion in black liquor systems. The European electric power industry has for several decades sponsored studies on resistance to alkali corrosion from biomass combustion (again an industrial environment analogous to a salt/soda kiln environment). The answers to many of a studio potter's questions on kiln materials for salt/soda kilns are already published in the refractory and other industrial & scientific literature, but these studies will not be found using 'salt firing' or 'soda firing' as internet search terms. LT
  12. PQotW: Week 37

    3,2,3,1 LT
  13. Beginning wheel throwing projects

    nerd, Based on your statement: "Even when I slow down, pay very close attention, still pull the top of the cylinder slightly off and open," and my observations of many students (including myself) I am guessing that you are pulling your hands of horizontally from the top and you are moving them rapidly while the wheel speed is slow. If so, the most likely cause is the surface tension between the clay and your hand - usually the fingers. The corrective action is: move your hand away from the clay surface slowly to allow the wheel to rotate several times as you move your hands off the clay. LT
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