Jump to content

Search the Community

Showing results for tags 'cracks'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • Ceramic Arts Daily Forums
    • Forum FAQ & Terms of Use
    • Studio Operations and Making Work
    • Clay and Glaze Chemistry
    • Equipment Use and Repair
    • Business, Marketing, and Accounting
    • Educational Approaches and Resources
    • Aesthetic Approaches and Philosophy
    • Int'l Ceramic Artists Network (ICAN) Operations and Benefits
    • Ceramic Events of Interest

Found 5 results

  1. Hi folks, again we have another quiz based on a book. I chose some of the questions this week to clarify terms that I have heard potters use interchangeably when they shouldn't be, so be careful. Week 7 _______________ is the ability of liquid to penetrate and be distributed through a material. It specifically relates to the working action of a dry clay surface when in contact with water. Porosity Shrinkage Marbling Absorption _______________is the quantity of the pores or voids in a clay body. Porosity Shrinkage Marbling Absorption _________ _____ is caused by a contamination in the clay, best described as a half moon shaped pit in the pot, with a light or dark nodule in the center. This can occur immediately after firing, or several years later as calcium chloride expands. Contaminated grog Lime pop Alkali salting Wet blistering Preventing S-crack formation in pottery in thrown pottery is dependent on __________________ alignment of the clay platelets during the throwing process. Much of this is dependent on the coning , opening up, and compression stages of the throwing. Linear asymmetric concentric random This weeks questions were taken from text in The Potters Studio Clay & Glaze Handbook, Jeff Zamek, 2009. Quarry Books Note from Pres: I could have gathered hundreds of questions from this book, but chose those which I thought would be of interest to the largest audience. I believe that I will return to some books after some time to add more. For those of you interested in glazes, and clay bodies, this is a well constructed and informative text. Answers: Absorbency and Porosity (Answers to both 1 & 2 are included in the text here) 1. (d) Absorption 2. (a) Porosity Two terms that are frequently used interchangeably but describe different conditions ore absorbency and porosity. Absorbency is the ability of liquid to penetrate and be distributed through a material. It specifically relates to the wicking action of ct dry clay surface when in contact with water. Porosity is the quantity of pores or voids in a clay body. ( Lime pop occurs when moisture in the air comes into contact with a carbonized lime nodule, causing its expansion in an unyielding tired clay body. This can occur when the pottery is removed from the kiln. li can also happen years later, as lithe expands (in the torm at calcium hydroxide). Lime pop is a semi-elliptical 1/8- to 1/2-inch (3- to l3-mm) crack in low-temperature bisque or high-temperature fired ware. A conical hole reveals a black or white nodule (lime) at the bottom. © concentric See image below.
  2. I have just poured the inside of a stoneware cylinder (test piece bisqued to 1000oC) with a transparent glaze that crawled horribly in a previous batch. This is a commercially mixed dipping glaze - very reliable by all accounts! Following advice here and elsewhere I let it stand and drew the excess water off the top. The glaze is now like pouring cream consistency. 100ml weighs 153g. I've poured the inside - about 3 seconds. As it dried the glaze cracked - see photo. What does this indicate? Can I just finger-sand it and dip the outside or am I destined for more disappointment?
  3. Hi there, I recently bought my very first kiln. It's VERY old, I think from the 60's or 70's. I was assuming it would have cracks in it, but I am a little concerned about the condition of the firebrick on the top. It's so crumbled it's almost falling into the kiln. I've seen a few websites that say the cracks don't matter unless the elements are sagging because of it, but I just find it hard to believe that with it this damaged they can still insulate (especially at the top). I've attached a picture of it. Can anyone tell me if I need to repair these bricks or not? Or does it just not matter if I can still get to temperature alright? Thanks in advance, Sigourney
  4. Crazing On Mugs Only!

    I have been using the same clay,slip and glazes purchased from a local ceramic shop. Everything has turned out beautifully but I got a new mug mold that will NOT stop giving me issues! The mug is slip cast using low fire slip. I fire to bisque..all good. Then I apply my glaze and fire..I let the kiln cool for at least 12 hours and still around the rim and handles I keep getting light crazing. No matter what I do..less glaze, more glaze, longer firing, soaking on high, the mug will still craze. Keep in mind, I haven't changed anything from the other ceramics I'm glazing, which all turn out without crazing, just the mugs are crazing. It's weird and I can't seem to figure out why or what I can do to keep this from happening. If you need any other info just let me know. I have a ceramic shop and really need to fix this issue asap! -Casi
  5. Hello! I had a couple of pieces that, freakishly, dried just fine...evenly...even thickness...all around good slab pieces... cracked in the kiln! I fired at the correct temp and somehow this happened. I've read about magic mud...and I was under the impression that it could be used on bisque fired pieces. However, my instructor told me that it couldn't? I wanted to see what everyone thought?
×

Important Information

By using this site, you agree to our Terms of Use.