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Magnolia Mud Research

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  1. Magnolia Mud Research

    Natural clay

    at the opposite end of the spectrum relative to Mark's experience. The yellow orange 'natural clay' from the bottom of my Texas pond still has bisque quality at cone 10. Even the terra sigillata made from it fire to cone 10 is not melted. I have to add lime and feldspar to get the clay to mature at cone 10. I do use pond clay straight as a decorative slip over just about any commercial clay body at any firing temperature; have also wedged that clay into commercial porcelain to give the porcelain some character. I recommend you try it both ways, with and without the fine sand. See what happens. LT
  2. Magnolia Mud Research

    Up to what temp can I vent?

    Have a look at this John Mason sculpture, images are at: and: http://www.artnet.com/magazineus/features/drohojowska-philp/ceramics-in-los-angeles-3-21-12_detail.asp?picnum=7 and pictured in the second edition of Daniel Rhodes book "Clay and Glazes for the Potter" has the following caption by Rhodes: "John Mason. Cross. This massive sculpture, made of solid clay, is 5 1/2 ft. high. A mustard-colored glaze partially covers the surface" John Mason American, born 1927 Cross Form, 1962/63 Stoneware with glaze 161.3 x 132 x 91.4 cm (63 1/2 x 52 x 63 in.) Gift of the Ford Foundation, 1964.71 http://www.artic.edu/aic/collections/artwork/20428?search_no=1&index=0 John obviously knew how to fire thick pieces without blowing them up. Also remember house bricks are thicker than one half inch! Large sculpture pieces are usually made with a clay body designed for sculpture and have a firing schedule designed specifically for sculpture. The half inch limit is seems to have developed for table ware and household storage containers. LT
  3. Magnolia Mud Research

    Turned Foot Rings On Mugs; Elegance Or Affectation?

    Take a look at the tap center video: The key is to learning the technique (at least that is what Fred Olsen told me) is to tap at the 10 o'clock position when the wheel is turning counter-clockwise. That works for me. like all skills practice, practice, practice is essential use a Styrofoam cup, beverage can, ... anything round. add some sand or lumps of clay to the can to simulate the weight of a pot also helps. a big help to centering is to trim the bottom round before removing the pot from the bat (or wheel) so that there is a round edge to use to start from when trimming. Centering pots that are not round or symmetric is a bit more challenging. I look carefully at the piece and arbitrary decide where the center of the foot ring should be, mark that spot with a pencil, and then tap center so that my mark is at the center. lt
  4. Magnolia Mud Research

    Surface Crack In Red Clay ( Terracotta)

    Tom, You should find these "texts" informative; the authors of both books discuss, and illustrate with examples, the physical chemistry of surface charges and the effects of those charges on solution chemistry. Title: The chemistry of soils Author: Sposito, Garrison, 1939- author. ISBN: 9780190630881 Publisher: Oxford University Press; 3 edition Edition: Third edition(November 21, 2016) and Physical Chemistry of Surfaces, 6th Edition Arthur W. Adamson, Alice P. Gast ISBN: 978-0-471-14873-9 Wiley-Interscience, Aug 1997 LT
  5. Magnolia Mud Research

    Re, sore aching hands, this has helped me

    Pres, At some point in the last two years, I saw a portable electric hand drill with several attachments that included a "putty gun" powered by the drill motor. I do not remember the brand name. You might inquire at your local hardware & tool stores. You can easily convert a putty cartridge to a clay cartridge for extrusions. LT added: take a look at: 18-Volt ONE+ Power Caulk and Adhesive Gun at Lowes or Home Depot. Just an example of what is available.
  6. Magnolia Mud Research

    Old Kilns - not in working order for years

    try this link: http://paragonweb.com/files/manuals/IM20-Ohmmeter Readings Paragon kilns.pdf LT
  7. Magnolia Mud Research

    Clay processing

    The answer to you question resides in the characteristics of what remains on the screen after completing step 4. If the "lumps" being retained on the screen seem to be stuff that belongs in the final moist clay, crushing them dry MIGHT, but not necessarily will, be the right thing to do. You can also crush these wet lumps and add the slurry back to the main batch. Crushing dry clay is dusty, and requires equipment to do so. I gather clay from my pond bottoms when they dry out. Crushing is only done to facilitate storage. However, small particles blunge more easily than big lumps. Its a tradeoff. I concur with Mark's remarks. LT
  8. Magnolia Mud Research

    Help! Cuerda Seca "dry line"

    I think your question is: What material can be screen printed on to ceramic tiles, will produce crisp lines, repel a water based glaze slurry applied by hand, and burnout during the firing. Does this "resist" material have to carry a black stain as shown in the photograph? I too have very little experience with screen printing. However: I have used white school glue as glaze resist. It does require a few minutes for the bead to dry. The industrial version of the same material is often thicker (higher viscosity). If the resist must carry a black stain, the addition of the stain material will increase the viscosity of the glue; the increase might enough to work just like screen printing ink. Since I have never tried mixing stain into the glue, I do not know if the glue will interfere with the "staining" function of the stain during or after the burnout. Most of the time, school grade glue will washout from cotton and polyester fabrics with water soaking and detergent; I expect that the glue would also washout from the printing screen. I wash out my glue brushes without any problem with warm water and detergent/soap - usually 10-15 minutes after using the brushes. LT
  9. Magnolia Mud Research

    terra sig vs. slip

    I use OM-4 terra sig on the bottoms of stoneware "pots" as a means to keeping the bottom smooth to prevent damage to the surfaces that supports the "pots" in use or in storage -- such as a vase sitting on the piano. The color of the bottoms with terra sig may be different than the raw clay body. If you are routinely using the same clay body, you can mitigate the color mismatch by making the terra sig from the clay body instead of from dry clay; the yield will be lower but the color match will be closer. A colleague use to use Redart terra sig over white stoneware instead of black underglaze for sgraffito decorations. The main differences between terra sig and slip are average particle size and solids to water ratio of the slurry. Application thickness is a variable that can become important; I have encountered peeling of the terra sig coating during the final firing when the application was too thick on cone 10 stoneware. For my work it was not a significant issues as the flasks were actually enhanced by the "ancient" appearance the flaking produced. I suspect that the peeling could have been overcome by applying the terra sig at the leather hard stage rather than at the bone dry stage. Slip and terra sig are analogs to buttermilk and skimmed milk. They do not look or taste alike but both are solids suspended in an water. Milk has always been a beverage, but some folks have made a living using milk for painting chairs and kitchen tables and cupboards. By the same analogy, you can find non-traditional uses and application techniques for terra sig and slips. I have used Redart (and also local clay) slips and terra sig on white and buff stoneware to produce contrasts; Redart terra sig over (and under) glazes to make contrasting marks on/in the glaze. Robin Hopper often recommended the "try it and see" approach. I am fond of (from the way back) Alka-Seltzer commercial's approach to many of the studio ceramic puzzles: "Try it; you'll like it! ...". As Edison said: “Just because something doesn't do what you planned it to do doesn't mean it's useless.” Pay attention to what does happen, and then think about how to use that "happening" effectively in producing your product. LT
  10. Clay toys The ceramic I class has frequently required a ceramic toy (~90% ceramic) as one of the final assignments. Students have made dolls, pinewood block derby type cars, checkers and chess sets of all sizes (one chess set used Raku pieces about 6-8 inches tall), jigsaw puzzles, dice, rattles, dominoes, blocks, and some other toys I don't remember. Some were glazed, others were finished with acrylic paints, and some were left unglazed. Many were just fired to bisque and then finished with paints and stains. The assignment was especially challenging to the students that thought only traditional function ware was pottery. The Ceramics II class had a similar assignment, usually early in the semester, called the trompe l'oeil assignment, which in my mind is a sophisticated version of the toy assignment. I had a classmate sometime back that worked with miniature cups, saucers, tea pots, bowls, bottles, etc. all less than 1 inch in size, all wheel thrown. She sold them at festivals for dollhouse ware. I have made fortune cookies, apple popovers, dice, puzzles, tic-tat-toe boards and a bowl of grits; some were fired to only bisque, others fired to cone 10, with either oxide staining, burnished clay, or raw clay as surfaces. The aesthetically successful ones were gobbled up at the club sales, the not-so ones become road rocks. I'll look around the storage cupboard and see if I have any pieces left for photos - don't hold your breath. Making toys requires an additional set of skills besides those of just manipulating clay. Toys are expected to be "toyed with", not just become decorations on a desk or in a cabinet. Therefore, the toy must also be functional and robust enough to be used as a toy. The ceramic pinewood derby car required several tries before the student got the weight balanced and the wheels and axles aligned in three dimensions. He learned a lot about making stuff from the assignment. LT
  11. Magnolia Mud Research

    cadmium red

    Have you considered using a thin coat of red between two layers of clear? The thin red coat over the clear should be semi-transparent, and the clear top coat would provide additional visual depth for additional translucent effects. LT
  12. 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
  13. 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
  14. 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
  15. 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
  16. 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
  17. 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.
  18. 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
  19. 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
  20. 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
  21. Magnolia Mud Research

    Jenkins kilns

    have you searched for Jen-Ken kilns? http://jenkenkilns.com/
  22. 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
  23. 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
  24. 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 )
  25. 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
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