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Magnolia Mud Research

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About Magnolia Mud Research

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    ceramic chemistry

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  1. Magnolia Mud Research

    Old Alpine Conversion

    three comments: 1. The updraft gas kilns at the local college have similar burner and piping arrangements as being used here and have shown no evidence of being overheated in the 12+ years I have observed them. The piping has only the galvanized and paint coatings from the manufacturer. The kilns are fired 1 to 2 times per week during the three semesters each year. 2. If you wrap the piping, be sure you thoroughly inspect the piping and structural members for corrosion prior to each firing. Piping in an environment with high humidity and an insulating covering will be subject to hidden pitting corrosion underneath the insulating material; the risk is especially increased when the piping is only heated periodically. 3. Consider the effects of wind blowing across the kiln area floor and interfering with the burners and pilots. You might need to add some portable windbreakers. Even though the college kilns are in a large shed with half walls on three sides (full wall on one), high wind conditions have shut down the kilns by blowing out the burners/pilots. Portable wind breaks are used to mitigate the winds. LT
  2. Magnolia Mud Research

    What should i mix in tio2 for cost reduction?

    A Whitewash Story: Once upon a time when working with a very dark clay body I needed to write on the pieces with black ceramic ink. To increase the contrast between the inked text and the background a white ink was concocted from a mixture of pure titanium oxide, a very small amount of EPK, and a pinch of soda ash, all mixed into a water slurry to a consistency between whole milk and buttermilk. The white ink was used on both green ware and bisque ware. When fired to cone 10 (reduction) the matte 'white rectangle' with black ink text was crisp, fully adhered to the surface as though it were a matte glaze. At another time (years later) a quickie white ink was made with pure titanium oxide, water, and liquid hand soap to write on the bottoms of extra dark clay bisque ware. The ink was fused to the ware and the text was a matte white; fired cone 10 reduction. I still occasionally use from the small jar of white ink. The recipe, as I remember, was two-three teaspoons of pure Titanium oxide, less than 1/4th teaspoon each of EPK and soda ash, and water. My reasoning was to use the EPK as a suspending agent and the soda ash and or soap was to lower the surface tensions and improve the wetting of the solid particles when mixed with water. These ingredients were chosen because they were readily available in the storage room at the time the ink was needed to finish time critical projects, i.e., the white ink was an improvisation under time constraints. Pure Titanium oxide is very white, reasonably refractory, and readily available (there was a big jar sitting on the bench). LT
  3. Magnolia Mud Research

    Glaze Defect

    If the defect is the small nearly bare spot about one third down from the top and just a bit to the right of the vertical center line, reapplication of some glaze and a refire probably should solve the problem. Refiring has its own set of concerns such as glaze movement (excess running), body slump, color and texture changes, ... . My guess is that the glaze was not adhering to green ware at that spot. Non-adherence could be dust, oily spot, finger mark, ... . LT
  4. Magnolia Mud Research

    Effects of iron chromate

    According to Mr. Hanson, https://digitalfire.com/4sight/material/iron_chromate_871.html : Iron chromate is a dense compound of iron and chromium. It is very refractory in oxidation, even with 50% borax and zero-alumina Ferro frit 3134 it does not melt. It is used in glazes to produce gray (with feldspar), brown (with zinc), red (with tin) or black depending on the base glaze and percentage and other coloring oxides present. … . LT
  5. Magnolia Mud Research

    Beach sand instead of grog?

    There are many "kinds" of sand. The geology and soil domains classify sand by particle size only without a concern for particle composition. According to Wikipedia, any soil material between about 2 mm (largest) diameter to about 1/16 mm diameter is considered to be "sand". The cement industry uses only "sharp sand" which is mined from large interior sand pits. The sand at the sea shore is likely to be dominated by fragments of sea shells which will decompose on firing to burnt lime. (Lime reacts with water vapor to form slaked lime and increases in volume significantly and will produces cracks and "lime pops" in ceramic objects, unless there is enough silica and fluxing agents in the clay to absorb the lime into the glassy phase of the fired ware.) Desert surface sand becomes rounded from wind movements. Hawaiian sand is mostly a mix of sea shells and lava remains. You would be wise to take whatever sand you plan on using and fire a small sample in a bisqued container to learn just what will happen with your additive to your clay body. First fire it in a bisque firing, then if survival occurs, fire the sample in a glaze firing. LT
  6. Magnolia Mud Research

    favorite throwing gauge / tombo to recommend?

    I use wooden coffee stirrers for most measurements. Make a mark on the stick, and stick to that mark.
  7. Magnolia Mud Research

    Best kiln for Elementary Art teacher?

    John Post has been teaching elementary students for years and years. Check out his website, and make contact from there get in touch with him , http://johnpost.us/ LT
  8. Backfill is an aesthetic detail and is used to avoid an abrupt "end" of a line. However, I always compress and round the transition from the handle material and the object material using the side of a 3mm diameter skewer so that there is smooth curved transition from the handle to the mug. Sharp (acute angle) corners are stress risers (in mechanical engineering jargon) that often lead to the origin of cracks in drying and firing. Rounding these joins reduces the likelihood of cracks. When examined up close, both of the illustration cups in Callie's post have this rounded transition at all of the joins; yet the blue cup handle seems to lack the general flowing lines of the handle on the white cup. LT
  9. Magnolia Mud Research

    firing temperature for bisque molds

    Slump and hump molds made from clay can be used at bone dry stage. . I know several potters that use them routinely. I often make molds with wet clay, cover the mold with plastic and paper, and make stuff, then use the wet clay to make something else, or recycle. LT
  10. Magnolia Mud Research

    Jenkins kilns

    have you searched for Jen-Ken kilns? http://jenkenkilns.com/
  11. Magnolia Mud Research

    Suitable glazes for highly textured pots

    two other approaches I overlooked: 1. If a clear glaze is acceptable, is to use a low fire (cone 04) clear or clear matte glaze. I have applied low fire clear with a sprayer to cone 10 work to seal the surface and gain some gloss. I apply it thin with a sprayer and have never had the glaze to run; I think that because the glaze melts just above bisque temperature there is enough pore surface to "sponge" excess glaze. 2. Apply sodium silicate to the bisque either by sprayer or by brushing. The sodium silicate will melt and react with the clay to form a glaze. I haven't tried it except on test tiles as part of different set of experiments. Control of application might require diluting the sodium silicate with water -- straight out of the bottle may be too viscous. LT
  12. Magnolia Mud Research

    does half a percent really matter?

    Oldlady asked: does half a percent really matter? ... it all depends on which half you are using (insert your favorite smiley face here)! LT
  13. I follow the concept in this quote from Chuck Close: “Amateurs look for inspiration; the rest of us just get up and go to work.” Chuck Close ( https://www.goodreads.com/author/quotes/166434.Chuck_Close )
  14. Magnolia Mud Research

    Suitable glazes for highly textured pots

    the use of soda ash, borax, or trisodium phosphate solutions, or mixtures, or "A" over "B" layering depends on your application skills and technique. I use a hand operated spray bottle with an adjustable nozzle that can be either a mist or a straight stream. The spray pattern does matter. all pots are with a cone 10 stoneware fired in school studio reduction gas kiln. image #3298 cup with shino inside and rim. outside sprayed with soda ash without trying to get a 'uniform' treatment. The dry areas are lighter hues and are less glossy. image #3333: cup with raw kaolin crackle on a buff cone 10 clay body the reddish spots areas were sprayed with soda ash solution. Image #3449cropcrop-x4 shows a pond clay crackle; left shiny side was sprayed with soda ash, right side no spray image #3449cropx-4-3-2 shows heavy coat of shino on rim, a swash across right with shino from a sponge, areas without (lighter hues) and with (darker red hues) soda ash spray. image #3451 closeup of dry area a bottom of 3449 showing contrasts of dry and sprayed areas. Note the shino mark in top right. LT
  15. Magnolia Mud Research

    Outdoor firing


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