What an impressive piece! Gorgeous! I am curious though, sometimes I get cracks on the top lip, outside wall. I throw thinner and with porcelain. Have you had any issues with the top and the outer wall, where they join, cracking?
Denise Thanx 1) When I throw the shoulder, I always compress the clay flat against the wheel head with a Rib. If the shoulder clay is less compressed it will shrink more than the walls. 2) Drying could be an Issue, the outer wall will dry faster than the inner Bowl. I normally just drape plastic sheet over a piece to help equalize evaporation. 3) If your batt is absorbent the shoulder and wall bases will dry quicker, plastic sheet helps here as well. But you should cut it off the batt as soon as you can to avoid an uneven adhesion to the batt. Then set it flat on the shoulder on an absorbent surface and cover it. Do not set it up right to dry the weight of inner Bowl will deflect the shoulder downward. 4) Porcelain Are you working cone 10 or cone 6? Porcelain being a primary clay (deposits mined in close proximity to its host parent rock). Suffer from poor particle size distribution. Which in turn imparts poor plasticity. Historically the Chinese addressed this problem by throwing a blanks 2 to 3 times the intended thickness and trimming a very dry leather hard blank to final form. You can see an example of that here: Jingdezhen, China - Trimming Porcelain Pieces ua-cam.com/video/o10UBL6oaIQ/v-deo.html Cone 10 Porcelain almost exclusively uses Calcium as it’s body flux. Cone 6 Porcelain is a modern hybrid. Very dependent on its Manufacturer. If your comfortable with your current clay, it’s firing and glaze expression. I would first look at your drying routine. If you feel it’s the clay find a thickness compromise, and embrace the path taken by Chinese Master. Hope this helps Jaime
Again WOW!
I'll admit it... I had to look up the word Torus! Great video- thanks for sharing
Thanks for your comments!
What an impressive piece! Gorgeous! I am curious though, sometimes I get cracks on the top lip, outside wall. I throw thinner and with porcelain. Have you had any issues with the top and the outer wall, where they join, cracking?
Denise
Thanx
1) When I throw the shoulder, I always compress the clay flat against the wheel head with a Rib. If the shoulder clay is less compressed it will shrink more than the walls.
2) Drying could be an Issue, the outer wall will dry faster than the inner Bowl. I normally just drape plastic sheet over a piece to help equalize evaporation.
3) If your batt is absorbent the shoulder and wall bases will dry quicker, plastic sheet helps here as well. But you should cut it off the batt as soon as you can to avoid an uneven adhesion to the batt. Then set it flat on the shoulder on an absorbent surface and cover it. Do not set it up right to dry the weight of inner Bowl will deflect the shoulder downward.
4) Porcelain
Are you working cone 10 or cone 6?
Porcelain being a primary clay (deposits mined in close proximity to its host parent rock). Suffer from poor particle size distribution. Which in turn imparts poor plasticity.
Historically the Chinese addressed this problem by throwing a blanks 2 to 3 times the intended thickness and trimming a very dry leather hard blank to final form.
You can see an example of that here:
Jingdezhen, China - Trimming Porcelain Pieces
ua-cam.com/video/o10UBL6oaIQ/v-deo.html
Cone 10 Porcelain almost exclusively uses Calcium as it’s body flux.
Cone 6 Porcelain is a modern hybrid. Very dependent on its Manufacturer.
If your comfortable with your current clay, it’s firing and glaze expression. I would first look at your drying routine. If you feel it’s the clay find a thickness compromise, and embrace the path taken by Chinese Master.
Hope this helps
Jaime