Mark C. Posted January 4, 2014 Report Share Posted January 4, 2014 The bars need to be all the same thickness-you do not need to rub the with ribs. just try to be all the same. Heres some info on this http://ceramicartsdaily.org/ceramic-supplies/pottery-clay/testing-123-how-to-test-clay-bodies-to-find-the-right-sculpture-or-pottery-clay-for-your-work/ Link to comment Share on other sites More sharing options...
cf66 Posted January 4, 2014 Author Report Share Posted January 4, 2014 oh thank you, that article is fantastic! Link to comment Share on other sites More sharing options...
Chilly Posted January 4, 2014 Report Share Posted January 4, 2014 The same clay body can be quite different depending on where its cut from the pug. I think this PowerPoint presentation Lecture #6 from Alfred University, "Particles: Orientation and Density", will explain it. http://claystore.alfred.edu/rawmats/presentations/Raw%20Mats/Class-6%20%28particle%20orientation%29.pdf Thanks Norm, that was really helpful. Page 34 has solved one of the puzzles we encounter at the day centre. Link to comment Share on other sites More sharing options...
Kohaku Posted January 8, 2014 Report Share Posted January 8, 2014 Average shrinkage of 12% +/- 2% is the total shrinkage. For many clays, most of this shrinkage will occur as the clay dries. There will be very little if any shrinkage during bisque. Norm- let me add my thanks for all of the detailed information. Just a quick question as a follow-up on the point above. I often need to fit a piece of Raku ware to a cone-six component (for example, Raku planter, cone-six base saucer). Given the assumption that there is little or no shrinkage at bisque, is it pretty safe to assume that there's also minimal additional shrinkage during a raku firing? I wouldn't think that there'd be much added vitrification at that stage... but someone please correct me if I'm wrong... Link to comment Share on other sites More sharing options...
Mark C. Posted January 8, 2014 Report Share Posted January 8, 2014 Average shrinkage of 12% +/- 2% is the total shrinkage. For many clays, most of this shrinkage will occur as the clay dries. There will be very little if any shrinkage during bisque. Norm- let me add my thanks for all of the detailed information. Just a quick question as a follow-up on the point above. I often need to fit a piece of Raku ware to a cone-six component (for example, Raku planter, cone-six base saucer). Given the assumption that there is little or no shrinkage at bisque, is it pretty safe to assume that there's also minimal additional shrinkage during a raku firing? I wouldn't think that there'd be much added vitrification at that stage... but someone please correct me if I'm wrong... My porcelain shrinks between 3 and 6 % at bisque-If you are asking if you then raku it will kit shrink more? The answer is yes if it gets over bisque temperature and no if its less than that. M Link to comment Share on other sites More sharing options...
Kohaku Posted January 8, 2014 Report Share Posted January 8, 2014 Average shrinkage of 12% +/- 2% is the total shrinkage. For many clays, most of this shrinkage will occur as the clay dries. There will be very little if any shrinkage during bisque. Norm- let me add my thanks for all of the detailed information. Just a quick question as a follow-up on the point above. I often need to fit a piece of Raku ware to a cone-six component (for example, Raku planter, cone-six base saucer). Given the assumption that there is little or no shrinkage at bisque, is it pretty safe to assume that there's also minimal additional shrinkage during a raku firing? I wouldn't think that there'd be much added vitrification at that stage... but someone please correct me if I'm wrong... My porcelain shrinks between 3 and 6 % at bisque-If you are asking if you then raku it will kit shrink more? The answer is yes if it gets over bisque temperature and no if its less than that. M I bisque to 1900, fire to about 1850... so I guess no additional shrinkage? Obviously, the important thing is for me to collect some hard data on my own clay body... Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.