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Magnolia Mud Research

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  1. Magnolia Mud Research

    Varied Perlite inclusion results

    Lucie Rie used rice to make voids in some of her work. I have used pine bark, saw dust (fine and chainsaw size), leaves, pine needles, string, and paper spit-balls in exterior slips to create textures. Literature sources include additives such as plastic chunks such as Styrofoam beads, wads of cotton or wool threads, etc. All of these techniques require extra monitoring to insure that the bisque firing is fully oxidizing, and that all the combustibles are combusted prior to the glaze firing. An alternative route to texture is to coat the surfaces with coarse clay/stone particles that shrinks differently from the main body surface. The different shrinkage generates open cracks during both the drying stages and during the fusing stages. Other sources of additives are crushed bisque ware, crushed fire brick, crushed construction brick (but NOT concrete/cement bricks), bauxite, ... . Globs of earthenware clay embedded in high-fire (cone 10) will produce gaps with oozing glazy melts in surfaces. I have added potting soil to decorative slips to change the fired texture. Crushed shells in slip could also be a route to surface texture if you keep the shells near the surface and washout the residual lime after the firing - if the lime is not removed it will slowly expand from rehydration and can lead to adverse structural consequences. The book you reference is worth reading, but you will probably gain more insight by just trying 'stuff' readily available from your current environment. The main thing to remember is to keep additives that require combustion, or the release of gas from decomposition, near the surface; otherwise you risk significant structural difficulties such as bloating or/and a "loss of containment situation". If you are using a community kiln, it is wise to keep you "Kiln Master" informed of what you have included into your ware prior to firing - KM's generally don't like surprises. LT
  2. Magnolia Mud Research

    Add saying plate or carving sayings into mugs

    The real 'trick' for managing burrs is timing - if the clay is too moist, or if the clay is not moist enough, rough edges are dominant. The 'right' time depends also on the type of tool being used. 'ball-point' tools compress and often make smoother edges; cutting tools leave sharper edges (and crisper looking text) that can be softened with a sponge at a slightly drier state than needed for cutting. Practice on slabs to find the out the right moisture level for your clay body and your tools and techniques, then begin to use the technique on the mugs and thrown items. This technique is a subset of Sgraffito (and Mishima) decorated ware. Sgraffito tools come in many sizes, shapes, types, etc. - store bought and homemade. I make mine using bobby pins and comfortable sized dowels (or sticks from trimming shrubs). LT
  3. Magnolia Mud Research

    Under-firing Kiln??

    Get in touch with Arnold Howard at Paragon. He can help you with your problem with the kiln.
  4. Magnolia Mud Research

    Gold-Colored Bizen Stoneware

    This article (detailed below) appeared in an recent ACS weekly newsletter: I'm recommending the article because the article 1. is about ceramic art (and craft); 2. is about chemistry (which is an important of the art); 3. provides insights of how atoms of Fe and Al can substitute for other atoms in crystalline and glassy phases in a ceramic matrix. the article details and links are below. The image is figure 1 from the article. read and enjoy. LT Alchemy in the Art of Traditional Japanese Ceramics: Microstructure and Formation Mechanism of Gold-Colored Bizen Stoneware Yoshihiro Kusano, Minoru Fukuhara, Taichi Fujino, Tatsuo Fujii, Jun Takada, and Mikio Takano Crystal Growth & Design 2018 18 (7), 4017-4021 DOI: 10.1021/acs.cgd.8b00368 You can read it online here: https://pubs.acs.org/doi/10.1021/acs.cgd.8b00368 ACS Editors' Choice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. Synopsis: The lustrous golden color of traditional Japanese Bizen stoneware was attributed to the yellowish color of a 100 nm thick Al-substituted hematite layer and the light reflected from the glassy phase. The color is reproducible in the laboratory through sequential heat treatments of Bizen clay pellets under oxidizing and reducing atmospheres with potassium supplied as a melting point depressant. Abstract: The microstructure and formation process of the golden color on traditional Japanese Bizen stoneware was investigated through model experiments. The current compositional and structural research of pottery fragments has revealed that the golden color comes from Fe oxide consisting of approximately 100 nm thick agglomerates of Al-substituted hematite (a-(Fe1–xAlx)2O3, x ˜ 0.05). The color is reproducible in the laboratory by sequential heat treatments of Bizen clay pellets under oxidizing and reducing atmospheres with an amount of potassium supplied as a melting point depressant. Lustrous colors such as silver and gold in Bizen stoneware have generally been attributed to the optical interference in superficial carbon films produced by burning wood fuel. Here, we show that the golden color is caused by the formation of Al-substituted hematite, not by the formation of carbon.
  5. Magnolia Mud Research

    Feldspar FFF?

    FFF feldspar is a brand of feldspar sourced from Finland. LT
  6. Magnolia Mud Research

    Cone 6 Red Stoneware Recipe

    Here is a clipped quote from Mel Jacobson's Clayart post dated: Mar 29, 2018: quote: [Clayart] cone6, mel6 recipe (open source) ... this is the recipe i sent to vendors, clayart friends, and i call it open source clay recipe...mel6 this recipe is the old mackenzie, minnesota clay 1965 or so. it is still my favorite, and [ *****] has used it for years. Fire Clay 50 (can be pounds etc. Goldart Clay 50 Ball Clay 25 Sand (silica) 25 Feldspar 12 Redart Clay 30 any oxide for color like ochre, iron ox, or black ox or, in comination in theory, you can use any quality stoneware clay recipe that fires to cone 10. they are much the same....the sand in this recipe gives it a very broad range for throwing and hand construction. the redart makes for a smooth, very long and workable throwing quality. if you need more glass maker...add silica about 8. this body is totally vitrified at cone 6. it has been tested. :end quote photos of the electric kiln fired ware are the last two images on mel's clayart website: http://www.melpots.com/CLAYART.HTML the clay body is exposed below the glaze line at the bottom of the mugs. LT
  7. Magnolia Mud Research

    Hudson River Clay

    Your logic is sound. tweaking is easier working with the 'original' mixture . Renormalize to 100% after you have what you want.
  8. Magnolia Mud Research

    Hudson River Clay

    Drop the lithium carb and see what happens. or swap sodium or potassium carbonate for the lithium carb. LT
  9. Magnolia Mud Research

    Hannahs Blue Fake Ash Glaze

    My guess is that you are not using cobalt oxide; probably manganese oxide; both materials are black powders. Try this: take a small white porcelain test tile, and mix a little bit of your "cobalt oxide" a little bit of baking soda in water and make marks on the test tile. Then fire normally. If the marks are not a strong blue, your material is not cobalt oxide!. As a footnote, I always use cobalt carbonate rather than cobalt oxide because the carbonate form is cheaper per atom of cobalt AND cobalt carbonate is NOT black. LT
  10. Magnolia Mud Research

    Hudson River Clay

    Mary, From the picture, both glazes seem to pull from the edges of the stamped areas - a characteristic I call 'breaking'. The Albany glaze seems to break more than the Hudson. My point about checking the 'true thickness' has to do with the thickness of the fired glaze, not the applied glaze. There is some areas on the Hudson that is lighter than the main areas; are these lighter colored areas thinner or thicker than the dark areas. Knowing that bit of trivia provides insights on application thickness, and how to decorate with physical texture on the surface (stamps, carvings, etc.). Hudson - in spite of its darkness - may be a glaze similar to the high fire reduction glaze "celadon" which is a super treatment for physical decorative texture. My thoughts about adding kaolin or ball clay to the mix is to see if this would either encourage micro-crystals to form (make the glaze more matte) and/or to stiffen the glaze somewhat. The Rutile, tin, Zircopax, etc are good ideas. I also suggest you do a line blend with your favorite clear glaze and the Hudson slip. Several years back a colleague did such a blend with Alberta slip and produced some very stunning combinations for sculptural work. I recommend you try the lemon test (see the Mastering Cone 6 Glazes book, and or the book's website for more on the test details) to see if food acids changes the appearance of the glaze. Also consider using the Hudson as a source of iron in one of your other favorite glazes just to see what happens. LT
  11. Magnolia Mud Research

    Hudson River Clay

    Different YES! WOW! Both are interesting ! Gold Hudson has potentialin the stamped areas are lighter in color. Check if the true thickness is thicker. Try layering Albany over Hudson and Hudson over Albany . Add some kaolin to Hudson and see what happens
  12. Magnolia Mud Research

    Mimic Large kiln operation with small test kiln?

    I suggest that you start testing a matte glaze that you routinely use in your "regular" kiln and that have examples to be used as a standard. Adjust the cooling cycle to get the test kiln to produce the same effects as your "standard" from your regular kiln. This cooling cycle for the test kiln should then become your SOP test kiln cooling program. LT
  13. Magnolia Mud Research

    Glaze firing for spoons and other flatware

    We have had good results using crushed oyster shells - normally used as grit for chickens - as support of glazed items. This technique developed from the use of sea shells as supports for fully glazed objects. We fire to cone 10 in a gas kiln. Should also work at lower temperatures. The shells are converted to lime (CaO) and wash out of the glaze. The rough spots require some polishing with a grinder or emery block. LT
  14. Magnolia Mud Research

    Plaster for wedging table

    I prefer 12 inch square concrete stepping stones for wedging. one side for white clay, other for not white clay. The concrete does not dry the clay as much as plaster which helps keeping the wedged clay moisture homogenous. For drying I use 12 inch terra cotta flower pot saucers. These do a good job of drying clay, stack easy, and are not as heavy as plaster - never had problems with porcelain picking up iron from the terra cotta. Both of these tools can be hosed down for cleaning when needed, and quickly return to a workable dry stage after being hosed. LT
  15. Magnolia Mud Research

    Space saving: wheel work station

    Nope, but I do have some wood maggots around the ponds.
  16. Magnolia Mud Research

    Toxicity of Tiny Clumps of Colorants in Glaze

    If you first wet the dry powdered colorants (Cobalt carbonate, copper carbonate, red iron oxide, etc) with alcohol (I use rubbing alcohol, but high end scotch also works) before adding the powder to your glaze mixture, the "clumping' is less likely to occur. The alcohol lowers the surface tension and quickly wets the particles. The prewetted powder, when added to the glaze slurry, will quickly disperse with stirring. The alcohol will evaporate and does not negatively effect the glaze. LT
  17. Magnolia Mud Research

    Help with raw glaze bubbles

    My thoughts: Item 1: there are two sources of gas for the bubbles: (1) from the open pores between the particles in the clay body, and (2) from gases being generated within the glaze as the glaze ingredients are forming a melt. Item 2: The glaze appears to be reasonably stiff, since the glaze line at the bottom of the mug is crisp without a 'jelly-roll.' Item 3: The inside of the mug is most likely cooler by several degrees K than the outside of the mug unless the mug has been heated for a significant and has equilibrated. Item 4: The bubbles are more present in the thicker regions implies that these are gases from item 1.2 above. Item 5: My strategy would be to increase the hold time at the peak temperature, or to raise the peak temperature a little bit. The hold time would give the glaze time to 'de-gas', the higher temperature would lower the surface tension and viscosity of the glaze melt. A bit of both would not be bad either. LT
  18. Magnolia Mud Research

    Can I substitute these chemicals

    Margie; Magnesium Carb and Manganese Carb different materials. Magnesium is element #12 in the periodic table; Manganese is element #25. They are NOT subs for one another. Magnesium carb brings magnesium oxide to the glaze which generally makes the glaze matte and generally does not significantly effect glaze color. Manganese carb brings manganese oxides to the glaze which makes the glaze more runny and produces dark colors - black and purple when I have used it. .... Zircopax and Zircopax plus are nearly the same material and produce the same effects. I would sub one for the other and not look back. ... Talc is talc. Use your talc for Texas talc. ... EPK and China clay are interchangeable. LT
  19. Magnolia Mud Research

    Metal rod that will fire to cone 5-6

    That is an interesting idea. Years back a class assignment was to use pyrometric cones as part of a series of sculptural pieces. I made small doll house cups and used small Orton cones as handles sticking straight out. The cone bent as expected and was a nice curved down handle. If cones of higher number than the firing temperature were used the cone just solidified without changing shape. If the cone was of a number lower than the firing temperature, the cone slumped and/or became glaze. A cylinder thrown with say cone 10 clay, and with cone 10+ cones embedded in the outside wall like climbing bolts in telephone poles, and fired at cone 6 or lower might be good bead rack. LT
  20. Magnolia Mud Research

    Hudson River Clay

    The program GlazeMaster was written by John Hesselberth; the book - "Mastering Cone 6 Glazes" was written by John Hesselberth and Ron Roy.
  21. Magnolia Mud Research

    are there any green food safe glazes

    For what firing temperature (cone)?
  22. Magnolia Mud Research

    BBC House of Arts and Crafts - Search for an authentic kick wheel

    Try to get in touch with Warren Mackenzie in Stillwater, Minnesota. He worked at the Leach studio and may remember who had what when regarding wheels.
  23. Magnolia Mud Research

    ^6 Copper Red Glaze Oxidation

    Neil, et .al., remember that silicon carbide is a material used as a strong high temperature refractory, aka kiln shelf. The oxidation of a silicon carbide particle produces a coating of silica, aka silicon dioxide, which functions as a barrier for the oxidizing agent. LT
  24. Magnolia Mud Research

    Metal rod that will fire to cone 5-6

    The issue with iron and stainless steel is the rapid oxidation at high temperature. Some alloys create fluffy flakes on the surface as the metal oxides. The flakes may be a problem . Try it and see what happens.
  25. Magnolia Mud Research

    Glazing Tools

    Soren, re plugging holes in the items: these techniques have worked for me on a variety of forms - never made an ocarina - so you will have to struggle to adapt for your product. : wax - small cake candles to plug the holes or just filled with liquid ceramic wax. school room white glue toothpicks and/or coffee stirrers tightly twisted news print my thumb (covering the hole) spaghetti (and other pasta when the shape fits) balloons inflated inside the form most of these techniques use something that plugs the hole and is expected to burn out during the firing. I try to verify that the holes are open and clean before putting the items in the kiln and that glaze is not attached to the "cork in the bottle" if you get my drift. LT

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