Transactions of the American Ceramic Society,; Containing the Papers Read at the Meeting ... Together with Supplementary Discussions and Other Matters Volume 13
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1911 edition. Excerpt: ...cooling as the most frequent causes of dunting. B. Mr. Weelans has not made plain in what way underfiring and overfiring of the ware produces, or even promotes dunting. From the testimony of Messrs. E. Mayer and. Maddox there is danger in underfiring only when the flint content of the body is too high. C. Want of tensile strength in the binding clay or too close a grain is productive of a weakness which I have often thought would follow from grinding the materials too fine, and for this reason I have thought it was fortunate for ' the potters that the clays they use are not more readily and completely disintegrated in the blunger, for if they were, the use of extremely fine flint and feldspar would cause the ware to be weak and punky, and very prone to dunt. Our students often overgrind their body mixes and get into these very troubles. The difficulties here are the same as those found by Professor Orton' when he attempted the use of too fine a sand or too "fat" a clay. I recently had a consulting experience with too thorough blunging of the body. A body blunged or treated with hot water until it gives difliculty in the filter press is very apt to produce unsound ware, an effect not always traceable to a separation of the body materials in the press. Bedford shale, when ground in the dry pan and worked to a plastic condition in a pug mill, can be vitrified with safety, but when disintegrated in a blunger and filterpressed, it is very prone to dunt if cooled too rapidly. I state this from sad experience. The reason? Primarily, too close a grain; secondly, defective structure caused by escaping moisture, combined water, etc.; and, thirdly, too tight a body to stand rapid cooling. I can believe that fusion need not progress...
- Paperback | 198 pages
- 189 x 246 x 11mm | 363g
- 13 Sep 2013
- Illustrations, black and white