LeeU Posted May 26, 2017 Report Share Posted May 26, 2017 Recently I ordered a commercial clay that is new to me - haven't fired it yet but have made a number of items. It is MC63B from Sheffield - the site notes that "63B Moist White Stoneware Pottery Clay is a dense, tight stoneware at Cone 6 . It is a blend of Kaolin, Fire, and Ball Clays. Contains No Talc and has good tooth for wheel throwing." I've noticed, when cleaning my tools and rolling pin etc. that there is consistently a strong, essentially "oily", residue left -not visible to the naked eye-and it takes a little bit of scrubbing to remove it from wood and plastic. Any idea what this is? My thought is from the ball clay but I really don't remember enough about clays to even know why I think that LOL Thanks in advance-it doesn't matter, really, I'm just curious. Link to comment Share on other sites More sharing options...
glazenerd Posted May 27, 2017 Report Share Posted May 27, 2017 Mica would be my first guess: excellent source of potassium and alumina. My second would be a smecite (bentone) clay, of which some do have a greasy feel about them. Although these are rarely used in a stoneware body... Nerd Link to comment Share on other sites More sharing options...
Dick White Posted May 27, 2017 Report Share Posted May 27, 2017 Nerd, do you think there might be any non-clay/non-mineral synthetic plasticizers in a clay body that might leave such a residue? dw Link to comment Share on other sites More sharing options...
glazenerd Posted May 27, 2017 Report Share Posted May 27, 2017 Dick: I have used MacAloid, v-gum t, hectorites, and some bentones: only one of which imparted a greasy feel. I use mica for several reason, and it does feel oily. Now there is the possibility that a man- made ionic inhibitor was used, that would cause this. There are several ionic compounds that are economically feasible for use in clay to impart plasticity. Nerd Link to comment Share on other sites More sharing options...
Mark C. Posted May 27, 2017 Report Share Posted May 27, 2017 Low fire bodies can be greasy feeling-I have never had much experience with cone 6 bodies(only fired one for a friend 15 years ago)-gummy or slippery may be mimicking grease feel. Link to comment Share on other sites More sharing options...
LeeU Posted May 27, 2017 Author Report Share Posted May 27, 2017 Doesn't seem gummy/slippery-feels oily and I can "cut" it with a natural soap, but it does not readily wash off even when being rubbed-but also it does not bead in water. I'll call Sheffield just out of curiosity. It doesn't hurt or affect anything, near as I can tell-just feels odd when washing up. Thx- Link to comment Share on other sites More sharing options...
Mark C. Posted May 27, 2017 Report Share Posted May 27, 2017 Since this topic is about strange stuff in clay (oil)?? or something like oil. Another topic of the week is what strange things have you found in commercial clay-I have a lot of additions to that topic. Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted May 28, 2017 Report Share Posted May 28, 2017 Is it some kind of naturally occuring contaminant, I wonder? Link to comment Share on other sites More sharing options...
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