The dreaded S crack Totally Totally Frustrated
Posted 13 January 2012 - 04:29 PM
Posted 16 January 2012 - 04:58 PM
Posted 16 January 2012 - 07:24 PM
It is hard to attempt a diagnostic this way. You are throwing these plates, right? I am going to try to explain a method I learned as best as I can. I learned it from just looking at an image of hand placement while throwing a plate. I am assuming you are right handed.
Wedge a ball of clay. After you have centered the clay, speed should be about medium to slow, open it up to a low bowl, leave about an inch (+-) on the foot so you can cut it off the bat and have room to trim. Use the heel of your right hand to push the clay down and out starting from the center moving to the left. Use your left hand to steady and hold the outside as you push with the right hand. Push out til the two hands meet. Use the fingers on your right hand to form the type of rim that you want. Practice this several times over and over til you get it.
After cut off, I leave the plate on the bat until it has firmed up a little bit. Then I remove the plate from the bat and cover with plastic for about a day. Then invert it to trim the foot. Then I sit the plate on a shelf to dry.
The plate throwing method is from the book Pottery A Basic Manual by Cora Pucci, Little, Brown and Company Publishers 1974, pg 94.
The book is out of print. Try to borrow it from the library or buy it on line.
I have used this throwing method for 37 years and I have never had an 'S' crack. I thought I could provide the image from the book but it would be a violation of Ms Pucci’s copyright.
Stop fussing at the clay, the plates and your husband, bad vibes won't help. If you get an 'S' crack which I doubt, but if you do, consider changing to a more friendly clay body.
Posted 19 January 2012 - 05:34 AM
Posted 19 January 2012 - 05:41 AM
Posted 19 January 2012 - 05:37 PM
Another thing that helped me tremendously -- I throw on Hydro Bats, almost exclusively. You don't have to cut the piece off... it will 'pop' off after a day or two. Especially helpful on wide pieces... plates, etc. I love them.
Posted 20 January 2012 - 07:23 AM
Posted 26 January 2012 - 06:55 AM
Posted 06 February 2012 - 03:34 PM
Oh, also, you can solve many of your drying issues by thinking of the bottom of a pot as being two surfaces of different lengths and speeds of motion, a plate like || and a bowl like )). If the bottoms are both the same length in the beginning the exposed side will soon enough be shorter since it will loose material (H20) the quickest and thus there will be less of it. The softer part will spread/give up cohesion to maintain equal lengths.
Yikes, one more edit: Don't let wide flat forms sit in a draft. Cover them with a towel or otherwise keep their drying slow and even. A pie plate should be on the bisque rack waiting to be fired in 24 to 48 hours, or so. Keep the drying slow and get them off the bat as soon as possible.