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Found 8 results

  1. Crystalline Glaze Chemistry Several have inquired about this specialty glaze in recent months, so I thought I would post an introduction into crystalline chemistry. The very first thing to do with this glaze is: throw out your glaze calculator and UMF spreadsheet: they do not apply to this glaze nor can you bring it into unity. Basic cone 6 through 10 crystalline recipe is: 50% ferro frit 3110, 25% zinc oxide, 25% silica 325m, and a seeding agent (see later). ^ Lithium carbonate flux additions discussed later. This is the basic crystalline glaze recipe, regardless of what cone you are firing to. However, crystalline glaze requires high fluidity of the glaze, so a high cone five is the minimum temperature level. It can be fired under five, but it takes a fair deal of chemistry to achieve it; so perhaps later it will be discussed. The reason you see so much variation in this basic recipe is because so many variables effect its outcome. Most of the variations are artistic preferences being inserted to control crystal size, population, and growth patterns. Likewise, the wide variance in firing ramp holds are due to kiln size, crystal development, peak cone temperature, and in many cases because the kilns were never calibrated by using cone packs or pyrometers to adjust thermocouple readings. An example: a ramp hold is stated as 2002F, but that same temperature could be 1992 or 2018F in your kiln. Frit 3110 is the standard and most reliable frit used in the crystalline recipe. There are frits used such as Fusion Frit 644, and others. If Ferro Frit 3110 is not available in your region, then use the chemical analysis of 3110 as a guide to compare available frits. Match the chemistry of your available frit as closely as possible to the chemistry of frit 3110. 50% of the basic recipe is frit, it alone makes up the glassy matrix of the glaze. Although silica is being added to this recipe, that silica addition serves a specific function other than being a glass former. Yes, the silica will add to the glass content, yet it is being added for feedstock for crystals to form. Frit is ground up glass that has already been melted at high temperatures; so the chemistry required to form glass in a glaze is not a consideration. Crystalline glaze requires a thick application of glaze, and crystals require a thick layer of molten glass to grow in. So lowering the frit level in this basic recipe also means you are restricting the glass level in which they grow. You rarely see the level of frit deviate from this basic recipe, and when it is adjusted: those adjustments are minimal. Crystalline glaze or crystals are chemically known as zinc-silicate crystals. Crystals form an ionic bond between zinc and silica: which is why equal parts of each comprise the basic recipe. Yes zinc adds opacity to the glaze and silica is a glass former: but neither addition is present in the recipe for those reasons. Zinc and silica are added and adjusted to form crystals, the additional glass formed or opacity added are secondary reactions. So the adjustments you see in various recipes are to manipulate crystal growth and population, and secondary “glaze chemistry†is not a consideration. Nerd (TJA 2017) Edit 8-12-2017 for spacing and grammar. Edit 8-13-2017 Explanation of temperature in first paragraph amended.
  2. Hey everyone! I'm in the process of creating a home studio, and I thought it would be a great idea to start making my own glazes. What are some good resources, magazines, or books that have helped you guys when it comes to introductory to advanced glaze making? Also, are there any tips or suggestions when I'm starting out! Thank you so much and any input would be greatly appreciated.
  3. Hi guys. I've started my aquaitance with ceramics and glazes half a year ago. I still have a very basic understanding of chemistry and I have several problems I'd like to ask about. First is clear transparent glaze. I made around 10 of them taking different recipes, but all of them contain bubbles. I've tried bisque firing in various temps, from 600 to 950C and second firing slow cooling, dropping and slow cooling, but bubbles are there and their quantity is similar in all conditions. I know commercial glazes don't have such problems. Please help me to figure out what is going on. My thought is that my raw materials are the problem. I have very few materials for glazes, those are: feldspar, whiting, borax, dolomite, talc, silica and kaolin. Substituting whiting with wollastonite didn't help. The runnier the glaze the less bubbles it has, but running is provided with whiting and borax and I have white clouds coming along with bubbles. Less flux - no clouds, but still bubbles. I imagine it is kaolin that gives a lot of small bubbles. Any chances to fix that? I have stains and wish to use them in underglaze painting, so I need to make a decent covering glaze. For underglazes I bought a few frits, I don't know their formula, seller keeps it in secret, only mentioning temp range. I have 1 lead flux frit melting on 710C and other leadless on 1100C. I need to fire on 1220C, so I guess some kaolin may help to lift temp of frits melting so the stains won't burn out, but more bubbles again? If you have info how to win the fight with bubbles please share. Sorry if made any mistakes.
  4. Glaze 101

    Hi guys! Id love to start making my own glazes however I have no idea how to! Where I used to help teach the other artist always made the glazes and now on my own Id love to learn! Ive tried looking it up and watching videos but I just can't get the hang of it! Any help with ideas, recipes, recommendations and options would be great!
  5. UNDERSTANDING GLAZE CHEMISTRY WORKSHOP (CER074SA) Sharon Campus of New Hampshire Institute of Art Nov 12 (Saturday), 10am – 3pm Professor John Baymore $129 This one-day seminar workshop will provide participants with a basic understanding of the core concepts that can impact the creation, use, and evaluation of ceramic glazes for studio use. The use of the popular Insight ceramic chemistry calculation software will be introduced, and the approach used to this can be applied to any ceramic chemistry software. Troubleshooting of fired results, "food-safe" qualities, health and safety, legal requirements, and ventilation concepts will also be touched upon. Handouts will be provided to all participants. Prerequisite: Intermediate or greater background in ceramic work To Register NEW HAMPSHIRE INSTITUTE OF ART 148 Concord Street Manchester, NH 03104-4858 BY PHONE Community Education Office (603) 836-2564 IN PERSON Manchester Campus: Mon – Fri, 9am – 4:30pm Registrar, 148 Concord St., Manchester, NH Sharon Arts Campus: Mon – Fri, 9am – 3pm 457 NH Route 123, Sharon, NH BY EMAIL CERegistration@nhia.edu ONLINE www.nhia.edu/CE BY MAIL New Hampshire Institute of Art Community Education Office 148 Concord Street Manchester, NH 03104-4858
  6. does anyone know how these are done? I've never seen color like this before and I buy from an extremely large ceramic/ glaze supplier
  7. I use a lot of slip trailing on my work. I had originally been using casting slip for my slip trailing because it was easier and at the time I had no place to mix slip, but now that I've made my own I'm never going back. A few months back I made up a big half gallon jar of B-Mix slip that I use both for slip trailing and for painting inside cups and bowls of dark clay so I can do a bright color inside. I like it really thick, like sour cream, just thinned out enough that it will come out of the slip trailer, but when it's thick like that, it holds its shape really nicely and gives a beautifully defined line, which I love. It was mostly just B-Mix and water, but I used a little vinegar so it wouldn't get stinky and it had maybe 8 oz of white stoneware casting slip too, just because I thought it would help my slip set up nicely. It worked out really well on every single clay I'm using right now. Over the next few months I used all but the last 1 1/2" of slip in the bottom of the jar, then I went a few weeks without using any. On Saturday I went to slip trail some things and it had turned liquid, like heavy cream, and it looked, felt, and behaved like pure casting slip and was very runny. It did not hold its shape when used at all. I didn't add anything since the last time I'd used it. I wouldn't have been surprised if it was thicker or dried out but this was just weird. The only thing I can think of is that perhaps the vinegar had something to do with it? Or is it possible that the casting slip had settled to the bottom of the jar somehow and that was mostly what was left?
  8. What The Heck is Glaze Chemistry All About? Sharon Art Center Campus of New Hampshire Institute of Art Professor John Baymore This one day, seminar-type workshop will provide participants with a basic understanding of the core concepts that can impact the creation, use, and evaluation of ceramic glazes for studio use. The instruction of the widely popular ceramic chemistry calculation software, Insight, and its priciples will be presented. Troubleshooting of fired results, “food-safe†qualities, health and safety, legal requirements, and ventilation concepts will also be touched upon. Handouts will be provided to all participants. Students are encouraged, but not required, to bring a PC or Mac laptop to test out a trail copy of the Insight software. Prerequisite: Intermediate ceramics skills. Limit: 15 Sat, July 26 / 9 am – 4 pm / 1 Day SCER074 / Tuition: $80 TO REGISTER: (603) 836-2564 MANCHESTER CAMPUS: IN PERSON: Mon – Fri, 8:15 am – 4:30 pm Fuller Hall, 156 Hanover St. BY EMAIL: CERegistration@nhia.edu BY MAIL: New Hampshire Institute of Art, Continuing Education Office, 148 Concord Street, Manchester, NH 03104-4858 BY FAX: (603) 641-1832 SHARON ARTS CENTER CAMPUS: IN PERSON: Mon – Fri, 9 am – 3 pm BY EMAIL: register@sharonarts.org BY MAIL: Sharon Arts Center, 457 NH Route 123, Sharon, NH 03458-901SCHOLARSHIPS: A limited number of scholarship funds are available to adults, youth and teens based on financial need. Scholarships are awarded on a first come, first serve basis. An application form and deadline information is available on our website at www.nhia.edu/ce or www.sharonarts.org. http://www.nhia.edu/assets/Uploads/PDFs/CE--CT/NHIA5866x9CEsum14web.pdf
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