How come bowls, cups, plates, etc. have ridges on the bottom?
Asked by
arnbev959 (
10908
)
December 19th, 2008
In art class we’re working with clay, and I’m making a teapot. Right now, the bottom of my pot is perfectly flat, but, looking through my kitchen, it seems like every piece of ceramic foodware has a thin ridge going along the bottom, with the rest of the bottom indented somewhat.
Example One
Example Two
Example Three
Example Four
Example Five
Mine looks sort of like this at the moment.
Is there a pragmatic reason for the ridge, or is it just aesthetic? Should I put a ridge on the bottom of my teapot?
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8 Answers
part of the manufacturing process. next time your at in n out, check out the bottom ridge of your cup for a bible scripture reference :)
Maybe related to the transfer of heat? With a flat bottom, more heat would transfer to table surface?
Talk to your art teacher. I think it might have to do with the ceramic firing process. When you put the teapot (or plate, or bowl, or whatever) in the kiln, it might stick to the shelf and break when you try to take it off. A ridge means less surface area is touching the kiln, so it’s less likely to break.
you don’t put glaze on the foot. otherwise it would stick to the shelf in the kiln
SRM
I think teapots don’t have the ridge, to maximize contact area with the stovetop.
Maybe the ridge helps the dish sit without rocking? Or reduces sliding on wet surfaces?
Foot rings serve an aesthetic and a practical function. They’re considered to be a more refined way of finishing the base of a vessel, allowing the bottom of the vessel to be glazed without gluing the vessel to the kiln shelf. Practically, they help ensure that the vessel will rest on a flat surface without rocking (it’s hard to get a flat bottom truly flat)
To create a foot ring on a thrown vessel, you let the vessel dry to leather hard, then fix it upside down on the wheel, centering it as nearly as possible and using wads of clay stuck to the wheelhead to hold it in place. The you use a loop tool to carve away a depression from the base, leaving only the rim (that’s a rough description; here’s more detail).
A hand-built vessel can get a foot ring formed separately and then attached, or built up from a coil of clay added to the base. You can also create three small feet instead of a complete ring.
If you don’t want to hassle with a foot ring, you should at least slightly indent the bottom of the vessel so that only the rim of the base will contact the table.
@jasongarrett: you don’t put a teapot on the stove—you put a teakettle on the stove. Then you pour the boiling water into the teapot, which brews the tea.
awesome answer, as usual, Harp!
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