Jump to content

Search the Community

Showing results for tags 'crazing'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • Ceramic Arts Daily Forums
    • Forum FAQ & Help Topics
    • 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 10 results

  1. Crazing 200X

    From the album Cone 3 Glaze/Clay

    200X of grazing: not seen by the human eye..

    © TJA2017

  2. howdy. I have been experimenting with low fire glaze that is safe for food use with stoneware clay. I am firing bisque at cone 05 and glaze firing to cone 05. My mugs look great and then I add in hot water and they start to craze. the craze is faint but, I can see lines. Should I bisque fire to 04 and keep glaze to 05? I have an old kiln so, I don't really want to use any high fire glazes so, this works best for me. Any advice will help.
  3. hi experts! Please help! One of my customers just sent me a picture of the plate that I hand-painted for them. They said they never used the dishwasher or microwave and were very gentle with it when hand washing and only used it for cold desserts. Please see the attached pictures. The cracking that you are seeing is on a plain rim dinner plate from bisque imports with only the Duncan Pure Brilliance clear overglaze on it. Why would this have happened? I will say that I had not sieved my dipping glaze in several months and when I did it was seriously clumpy and the sieve got clogged really quickly. Could that have been the reason? We are going to do some testing on some glazed plates since we sieved it, but if you guys have any other ideas, please help!!!
  4. Laguna 65 And Crazing

    Hi there, I have been using Laguna 65 for years now and have enjoyed throwing with it and love the color once fired. I have been having serious issues with crazing from the beginning, and now with my new surface designs I would really prefer a good glaze fit. I have tried several different clears on this clay body including commercial Amaco HF-9 and several clears that I mixed on my own. ALL OF THEM have crazing. Normally delayed crazing. Of course this indicates that there is a poor fit with the glaze. But after all of the glazes I have tested I am wondering if there is something I am missing with the clay body itself? I fire to cone 6. I was wondering if anyone else uses 65 and has either A)found a clear glaze that works successfully for them or has suggestions for what I might be able to do to solve my issue.
  5. Hello, I am new to this forum and new to mixing and firing my own cone 6 glazes in an electric kiln. Boy, what a learning curve! I have much to learn. I'm grateful to you guys for posting so much useful information here:) I just fired a small kiln load of pcs of different stoneware clay bodies with Turner White recipe that I found on Ceramic Arts Daily. I thought it would be a stable fool-proof glaze so I regrettably did not test. My kiln has been overfiring, so this firing I made the adjustment of firing to cone 5, holding for 15 minutes. My pyrometer cone reached cone 6, so temperature is good...but....maybe some improvements still need to be made. The turner white came out different on different clay bodies. On Venus White clay (which has some grog) and B-mix clay, it came out an undesirable chalky, super matt. The surface almost feels like clay body. There was also some crawling happening on the Venus White clay body pcs. On red b-mix and electric brown, the finish was a tiny bit more satin matt...but not much more. I also noticed a lot of crackling, popping well after the pieces had cooled down. On some of the Venus White pcs, lots of crazing where I had dripped Leach Blue over the Turner White. What do you think the problem could be? Could some of this have to do with kiln temperature and/or cool down? And could I save these pieces by coating with clear glaze and re-firing? Or mix a new batch of turner white glaze with additional chemical to increase sheen?
  6. I've been throwing with Standard Clay 630 (^6 white stoneware) this year and have really been enjoying using it. However, I used a few different commercial glazes with it and have found that some of them are crazing. For example: Amaco HF-9 Zinc Free Clear Amaco PC-40 Celadon Amaco Sahara Yellow Coyote Light Blue Gloss All of these are translucent, so maybe that's the common thread? Because Amaco's Ultramarine, Amaco's Amethyst, and Coyote's Buttercup didn't craze at all. But I tried my local studio's zinc-free clear, and it didn't craze. It's not the cooling, because nothing is being fired any differently than other pieces that don't craze. So I'm thinking it's a COE / glaze fit issue...but I am a total newbie at glaze chemistry, so I bow down to the collective knowledge of the forums and ask if there's anything I can do to my commercial glazes to make them fit. Other than changing clays, of course. Which is probably what I'll have to do, but I like the 630 the best out of the ones I've tried and I really love the celadon and light blue glazes... Also, how serious is this breed of crazing? Is it really *that bad* when it comes to using them for food/drink?? (Regarding clays.....I know some of you swear by clays made by Highwater, Laguna, etc., but I live in Pennsyltucky and getting anything other than Standard isn't an option right now. Also, I am a hobby potter and porcelain is out of my current league.)
  7. Crazing Issue

    Hello all!! I am having an issue with my small tiles crazing. Very fine lines are showing up after a month. I am using b mix clay to ^06 first then paint/glaze then firing to ^5. I have made over 100 triangular tiles. Can I glaze them again with clear glaze and fire to a low fire? Or are these trash!!!! Thanks!!! The crazing is actually pretty so I don't have a problem with it as far as visuals. My concern more so is the moisture issue. Linda
  8. 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
  9. Hi, I am a total newbie to making glazes and I just ran some tests at ^6 on Laguna Frost. My objective was to find a clear glaze that didn't craze, and I tried a few glossy and a few satin/matte options hoping to find some success. To test for crazing, I used a procedure described in Mastering ^6 Glazes, where the sample is heated in an oven at 300 degrees, then quenched in water. Then I used a blue sharpie marker to reveal any cracks that formed. All of my samples crazed after this test, so I am hoping to get some advice on how to interpret the results. I've attached a couple images of the results. The tiles are arranged in order of the expansion coefficient (as generated in GlazeMaster), with the lowest on the left (6.29) and the highest on the right (7.16). The tiles labeled 9, 6, and 11 are satin/matte and the rest are glossy. Tile 15, on the left, is the low expansion recipe from Mastering ^6 Glazes, which I had been optimistic about since the book suggests it won't craze on the majority of Cone 6 bodies. I've read that adding silica will help solve crazing issues, but since even the low expansion glaze crazed, it leads me to wonder if I am doing something else wrong that is causing problems with the clay body itself? I bisqued the tiles to ^04, but did not do any sort of controlled cooling on the bisque. Also, the cracking seems to extend pretty deep into the porcelain body, as shown in the detail image. I added more ink to the sample on the unglazed portion to reveal the cracking. Is that a normal byproduct of crazing, or is it possible the body itself is cracking and the glaze defect is actually appearing as a result of that? A few more details: The witness cones on the same shelf as the test tiles show the 6 cone bent properly and the 7 cone just starting to lean. I tried to do a controlled cooling using a portable pyrometer (it's a manual electric kiln) but suspect I went a bit faster than is recommended in M^6G. When I opened the kiln to take everything out, I got a reading of 185F on the pyrometer, so it seems that should have been a safe temperature. Any advice on next steps I should take would be appreciated. Adding silica to the glazes is on my list, but are there other things I should be considering? Thanks in advance for any help.
  10. Hi all, I have been throwing with Babu porcelain, glazing with Reeve's Clear glaze. I fire to cone 10, in a light reduction, gas kiln. I notice that the Reeve's clear seems to craze more than I want in a food vessel, even when thinly applied. It seems to fit stoneware better than porcelain, with much less crazing. I know Babu shrinks more than stoneware, so it's clearly a glaze fit issue. Has anyone found a better clear glaze that doesn't craze, for use on cone 10 porcelain? Do you have any suggestions as to how I might get a better glaze fit on Babu? I use Babu because of its clear, white color. I'm willing to use a different porcelain if I can get better results and keep the white color. Any ideas? It's very frustrating. I want to use this clear base and add colorants, such as Mason stains to get translucent, "celadon-like" colors. Thanks for any help.
×