Clay Question - Little Loafers Or Standard White ClayWhat are the differences?
Posted 09 August 2013 - 05:17 PM
So has anyone used both of these clays? What is the difference between the two? Do you consider one better than the other and if so why?
I'm just getting to the point I know what Little Loafers is going to do when I use it and am really leery of switching over to a whole different clay. Will I have to start all over in my learning curve or unlike the books say is there really not that much difference between the clays? The books all say when you change clay you have to start over with how it handles, redo all testing and glaze fit can be different as well.
Any input from those with experience with both clays would be greatly appreciated.
Posted 09 August 2013 - 05:30 PM
i used to use standard clay. it comes from carlisle, near pittsburg. did not use that particular white clay but found that some of their products work best for throwing OR handbuilding. since it came from only 200 miles away i would pick it up while traveling.
highwater makes the little loafers and it is a great all around clay, throwing well and i use it for slab work. it is closer to you but i do not know how your group gets the clay so shipping charges may not matter.
whatever you decide, find out if the clay will work for all of you, throwers or handbuilders.
why can you not buy both clays so everyone would be happy?
Posted 09 August 2013 - 05:48 PM
I do know some of the other potters have had cracking issues in the past with Little Loafers so this may have something to do with it as well. I personally have never had an issue with stuff cracking but then I dry things really slowly in a drying cabinet so the levels are pretty much constant. I have to dry this way as I do a lot of surface decoration and a longer "open" period works best for me. I don't do wheel work so personally if I had to choose I would choose a clay that works best for hand building.
I'm just trying to educate myself so when next I am asked I can give a more educated answer as to why one or the other would be better for me.
Posted 09 August 2013 - 05:59 PM
Standard 240 is a nice clay body. We use several thousand pounds a year in my studio. It does require good compression of the foot to prevent s-cracks, but it's a good body. They have a new cone 6 white, #630, that is more forgiving, as it has fireclay in it. Slightly more texture, but not noticeable when throwing. Never used Loafers...
Kiln Repair Tech
Owner, Neil Estrick Gallery, LLC
Posted 10 August 2013 - 03:22 PM
Posted 10 August 2013 - 10:40 PM
Posted 12 August 2013 - 09:20 AM
Those absorption numbers mean exactly what you think they mean and you are absolutely right. Lower absorption is better for functional wares.
Shrinkage on the other hand is not the same as expansion. Shrinkage in clay happens usually happens due to loss of water on drying and ???not quite sure in firing. Maybe quartz inversion and also loss of more chemically bound water???
Expansion is due to absorbed or lost heat and is repeatable. Shrinkage is not repeatable. Once it has shrunk it will not go back.
When a pot expands due to absorbed heat, it will contract when it cools.
The glaze fit is due to how similar the clay and glaze expansion rates are. This is called "Coefficient of Thermal Expansion" or COE for short.
No matter the shrinkage, if the glaze and clay COE matches the glaze will fit. Even if the shrinkage is different. As a result the higher shrinkage may not affect glaze fit at all but it may have an effect on how well the clay deals with attachments such as handles as it dries and warping as it dries.
Ask Highwater and Standard if they publish COE's for the clays in question and compare.
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