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Magnolia Mud Research

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  1. Put the underglazes on at the bone dry stage and bisque fire. The underglaze will be fused to the bisque ware enough to withstand being washed, rubbed, and otherwise handling. The integrity of the bisque fired underglaze now be equivalent to the integrity of the bisque ware. Or simply re-bisque fire the bisque ware after applying the underglaze. LT
  2. Long ago I conducted a series of tests using water color paints on green and bisque ware to see what happens when fired. Was interesting! All of the “paints that contained metal based ingredients produced a color similar to the use of that metal oxide in a stain or glaze. Using oil paints and school wax crayons also produced marks. Therefore mixing a thin mixture of the “right “ material and brush technique one would probably get the effect you want. Try it and see what happens. LT
  3. I have used a low fire clear commercial glaze on cone 10 stoneware (and porcelain) fired to cone 10 reduction without any problems. Also used that clear glaze as a “base glaze” with added oxides for high fire tests. I suggest you make a test run with the stoneware in something similar in shape and thickness to confirm. low fire glazes are fully melted at or near bisque temperature of stoneware and the open pores of bisqued stoneware soak up the glaze like a sponge. LT
  4. @Olinda, Keep in mind that iron in your water supply produces stains on glazed porcelain (aka tubs, sinks, and showers) that are extremely difficult to remove without some chemical assistance. Try it and see what happens. Adding a little sodium silicate to the iron oxide and water might help when the water evaporates; the sodium silicate becomes "water glass" which was used to seal flues on stoves before more modern 'stuff' was marketed. LT
  5. To decipher the correct firing temperature of an unknown clay, my recommendation is to make some "cones" [in size and shape similar to the pyrometric cones] and place them in a pad of your normal studio clay body and fire them to your usual temperature to see what happens. If you like the results, then make some forms. If the tested clay melts, then you know you need to lower the firing temperature for that clay material, or use it as a decorative coating on your regular clay body. When I first started in ceramics, the professor had us using low fire (cone 05) red and white clay bodies for ware we fired to cone 3 oxidation in a gas kiln. The ware was fully mature, did not slump, nor did melt. Slumping began around cone 5. Later on we switched to cone 10 reduction, and the low fire clay bodies were usable as decorative glaze. I use commercial red and white terra cotta clay bodies as decorative coatings on bowls, containers, and sculpture for my cone 10 reduction ware. The red clay becomes a dark reddish black semi-gloss coating and the white clay becomes a matte white coating. The thickness of the coating is a significant variable for the outcome. LT
  6. moh, based on your statement, "The blue you see in the pitted area is the color of the first glaze layer", my speculation is that the sprayed layer failed to adhere properly to the surface of the material already on the pot. This implies that the sprayed layer was too thinly applied, or that the sprayed material dried before being attached to the surface and therefore did not adhere to the substrate. LT
  7. What concentration of HCl is the bath etching the ware ?
  8. Checkout the document for canvas bats on Vince Pitelka’s website www.vincepitelka.com
  9. Are these and/or your pots fired to maturity or to a semi-maturity? iI have been using dry clay powder to wet green ware for surface texture, using dry sand might also work, if you are interested in the not so smooth texture. LT
  10. I would try adding 60 grit sand to a clear glaze and see what happens.
  11. Use tarpaper or cardboard bats between the plastic bat and the clay. Use clay slip only at the rim of the tarpaper bat to hold the tarpaper to the plastic bat. Then run cutoff wire between the tarpaper and the plastic bat. Check out tarpaper bats at Vince Pitelka’s website. Vince PitelkaProfessor Emeritus of Art/CeramicsAppalachian Center for CraftSchool of Art, Craft & DesignTennessee Tech UniversityNow Residing Chapel Hill, NCvpitelka@dtccom.netwww.vincepitelka.com
  12. If Mr. Griffin Grip we’re on top of the business, he would have already dreamed up a “trimmings catcher add on” that would fit all wheels.
  13. I use commercial cone 05 clear glaze at cone 10 and have never had a problem! Also have used it successfully at cone 3 and cone 5 and on raku which is a fired a smitten above bisque temperature. YMV. Have also used that clear as a base glaze for other ingredients such as rutile, iron, kaolin, etc. tests at cone 10 so far nothing unexpected has resulted. Crazing can be adjusted with silica most of the time. I also use low fire clay bodies as a decorative slip on cone 10 reduction fired ware; sometimes low fire red/dark clay body will run if applied too thick. Testing is necessary!
  14. who is the "they" that studied these bowls? There is more happening than just iron crystallization. LT
  15. consider using dryer clay and/or dusting the inside of the wood mould with dry calcined kaolin as a release agent. LT
  16. four comments on keeping in progress items moist: 1. I wrap my leather hard work with several layers of 'cling' type plastic wrap (aka Saran wrap); the plastic is pressed tight against the clay to prevent uneven dry spots. I then loosely wrap the item with the same plastic I cover stuff for overnight storage. I once kept a large 12in tall leather hard vase for a summer and two semesters before finishing the sgraffito work - the vase was a little bit drier, but was still leather hard. 2. I made hand impressions in soft porcelain slabs from Nashville back to Texas with each slab wrapped tightly in Saran wrap placed in side a zip-lock plastic bag that had been sprayed with water in the plastic bag. They were kept from June to November in a closed Zip-loc plastic box. They slabs were still flexible enough to shape into cups. 3. I often store wet ware in a tight fitting plastic box which has a small cup of water also in the box, or with the ware sitting on a brick or shard to keep off the bottom. They will stay wet for weeks if the water doesn't evaporate from the cup. One bowl was stored in a bucket for over a year at the wet stage. The approach in comments 1 & 2 is to minimize the amount of air between the ware and the plastic to an minimum; the air breathes as the temperature rises and falls from the initial wrapping; when the breath press is outward, the air cares out some moisture away from the ware. The compressing the wrap against clay surface minimizes the volume changes with temperature changes. The second outer wrap also lowers the drying by providing additional barriers that the moisture must pass before being lost to the ambient environment. The approach in comment 3 is similar but as the container breathes the water in the air is replaced from the source of liquid water in the open cup/bottle. As long as there is liquid water in the open cup/bottle, the moisture in the air is in equilibrium with the water and with the ware. 4. Consider under-the-bed clear plastic storage containers for storing plates in progress. LT
  17. Go to the 21st century kilns website and get the book also available from Paragon kiln website . The book will give you the information you need. LT
  18. Johnny, Test the vase with water that has a “tad” of soap and/or detergent to see if the “stuff” remains water resistant. Flowers often contaminate the water after a few hours; many florists put a package of powder that slows the wilting of the flowers. My guess is that the “liquid glaze” depends on the high surface tension and wetting character of pure water; adding detergent lowers surface tension and increase wetting. Or add some rubbing alcohol. Hopefully the “liquid glaze” lives up to the advertisement. LT
  19. How deep is the water on main Street when it rains? Who gets use the high ground during the rain? Think about the water that falls on the buildings around the area; where does that water go and will that water impact you where your booth will be located on main Street? Will you be prepared to be located at the bottom of the hill or at a low spot in the road? LT
  20. I agree; But apple vinegar smells better than plain water and does change the local area to a slightly more adhesive environment. My handbuilding is generally done with soft clay. The corn syrup (it's sticky by design) in the SPOOZE mix helps with adhesion of stiff clay. LT
  21. Yes, vinegar works fine. So does plain water, and a few other liquids. I have used them all. the compression of the pieces is more important than the choice of liquid. Also wait until the sheen of the applied liquid goes away before putting the clay pieces together. Too much liquid in the joint is not good! LT
  22. Have you cleaned the thermocouple tip? A buildup of corrosion on the tip (which is the working part of the device) will lower the true thermocouple reading which is what the controller uses to decide if the target temperature has been achieved. The corrosion insulates the thermocouple. Cleaning will remove the insulation an the temperature reading will be closer to the temperature of the ware. LT
  23. so does baking powder, baking soda, table salt, and trisodium phosphate -- always applied as a solution in water. Try drawing on raw clay with a brush using a baking soda solution (or any of the above) as ink.
  24. A work-around is to leave a couple of small throwing sponges in the splash pan; when the water gets high, squeeze the sponge over your throwing water bucket; then drop the sponge back into the splash pan. Perty soon you will be using the splash pan for water rather than the water bucket.
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