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    • Jennifer Harnetty

      Moderators needed!   12/08/2017

      Ceramic Arts Network is looking for two new forum moderators for the Clay and Glaze Chemistry and Equipment Use and Repair sections of the Ceramic Arts Network Community Forum. We are looking for somebody who is an active participant (i.e. somebody who participates on a daily basis, or near daily) on the forum. Moderators must be willing to monitor the forum on a daily basis to remove spam, make sure members are adhering to the Forum Terms of Use, and make sure posts are in the appropriate categories. In addition to moderating their primary sections, Moderators must work as a team with other moderators to monitor the areas of the forum that do not have dedicated moderators (Educational Approaches and Resources, Aesthetic Approaches and Philosophy, etc.). Moderators must have a solid understanding of the area of the forum they are going to moderate (i.e. the Clay and Glaze Chemistry moderator must be somebody who mixes, tests, and has a decent understanding of materials). Moderators must be diplomatic communicators, be receptive to others’ ideas, and be able to see things from multiple perspectives. This is a volunteer position that comes with an honorary annual ICAN Gold membership. If you are interested, please send an email outlining your experience and qualifications to jharnetty@ceramics.org.

ekoenig

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  1. I have completed the firing of all of the pieces and have had no improvement on the cracking even though none were flat on the kiln shelves. In fact, I think more pieces cracked this last time than in the two prior loads. I can only surmise that they were dried too fast, had stress from cut points, and possibly had cooling problems. I also wonder if the clay itself was not a good choice. Anyway, I don't think I will attempt this project again. Too many issues, and too sad to hand people pieces with huge cracks in them. I have been firing things for 8 years and have never had SO MANY problems! Anyway - thank you for trying to help me. Your ideas were good and I will remember them in the future.
  2. Update on my problems: I tried a small load (two flat items) using various items to lift the pieces off the shelves. One cracked badly and the other came out beautifully. I have noticed that the top shelf pieces have fared the worst so will put a shelf over the top next time. I made a bunch of triangular shaped pieces to use for lifting the work off the shelf next time. Fired them as greenware to cone 6 and it worked fine. We'll see what happens when I use those. Also, I called the store where I get all my supplies (Seattle Pottery Supply). The person I talked to did not believe the problem was the contact with the shelf but that they had dried too fast in this dry hot weather we have been having. She said they probably had small cracks after the bisque firing. I do think there may be some truth to this idea. In the past I have had more problems with cracking in the summer months, now that I think about it. Could this be a possibility with the hearts, Jojess? By the way, I used Oatey brand "epoxy putty" to fill the cracks on one of the most rustic textured pieces and it came out great! Not that that's a real solution, but since I am keeping it it works in this case.
  3. Thank you - I will definitely get them off the shelf. I will also use the cutting method you described next time. Holes made from drinking straws may work nicely as the starting point. I really appreciate this forum. Although I took some classes years ago in making pieces I learned nothing about firing, and am on my own when troubles arise! Oh - one more question - do you think the stacking and adhering (someone said applique?) technique is doable, or bad practice?
  4. Thanks so much! I will definitely try the coils on the next batch. Or sand (since I am not going to be doing a bisque firing anytime soon) - is it really okay to just use play sand??? I don't think it is only stress points though. I went out and looked at the finished pieces and three of the worst cracked ones have no points cut into them as you can see here. Only one of these is around 8-9" wide. The other two are smaller. Other pieces in the load came out fine. Could it somehow be the kiln? By the way, the clay we used was Sea Mix w/ sand from Seattle Pottery Supply and I fired to cone 6.
  5. Cracks during glaze firing

  6. Here are the two I made with severe cracking on bottom layer. They are about 8" across. Also, getting this figured out is crucial because I had planned to do the same project with the public at the library where I work. Thanks!
  7. Hello, I have a similar problem and it involves a lot of pieces made by a lot of people so I hope someone can help. I like to have clay parties to share the joy of working with clay, so I got together a bunch of co-workers and we made about 25 suns/flowers. I rolled out the slabs ahead of time to make the process faster. The ides was to cut and embellish three sizes of circles, and bisque fire them unattached. Then we would glaze them in three colors, and I would stack them to adhere during firing. All went well with the bisque firing. I started to worry about whether this stacking of glazed pieces would actually work so I glazed some I’d made first and got big cracks on the bottom, largest circle. I then assumed it was because of the different glazes reacting to each other. I told everyone we could not stack the pieces and they’d have to use glue after the firing to attach their flowers or suns together. Everyone glazed their work and the plan was to not stack them. I loaded the kiln and fired about half of them, unstacked. I peeked in this morning and saw one of the bigger pieces on the top shelf was cracked badly, with glaze having gone down into the crack (unlike another post here) So - I now think that instead of blaming it on the stacking method it may be that I need to use sand or coils beneath the pieces. I hate the idea of ruining everyone’s careful work. Please help if you can. PS - Can images be attached here? If so, I could upload a photo.
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