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Lewis 4/13/05

> "Alex Chaihorsky" > writes:
>
>>> I have found that among the many YiXing GungFu teapot "styles," those well
>>> made with a straight upward pointing spout work best in the drip
>>> department.
>>> The last drop is "pulled back" into the pot, as it ought to. This
>>> has to do with design much more than clay roughness and surface
>>> tension. Take it from Michael, the used-to-be potter.
>>>
>>> Michael
>>
>>
>> Its design plus material plus size and shape (that defines the
>> dynamics and geometry of how fast it is rotated around its
>> horizontal axis during pouring. Straight upward design works good
>> for smaller pots and yixing clay has very high surface tension
>> (watch drips of water sitting on its surface at different slope
>> angles and compare that with the behavior of water drops on glazed
>> porcelain) Same design does not work for large kettles at all also
>> because that design implies lifting the pot quite high and rotating
>> it at he higher angle, which is difficult with heavy pot. That is
>> why traditional kettle has a bent spout that allows for smaller
>> rotation angle and almost no lift.
>> Yixing pots are meant to be emptied into chahai by placing them
>> almost upside down with their spout inside chaihai opening. That is
>> not at all the dynamics of the usage of large teapot or kettle. Thus
>> the differences.
>>
>> With al due respect to a potter from a scientist.
>
> Neither potter nor scientist, I hesitate to raise a question I should
> have asked a bit earlier: Isn't surface tension a property of liquids,
> e.g. tea liquor, not solids, e.g. teapots?
>
> /Lew

Yes. But, I'm just a poor country boy. We used to test teapots of the
same size and made of the same clay and glaze formulae, and found that some
poured better than others; that is, some did that pull-the-last-drop-back
trick. The question for us was always, Why this one and not that one?
Anyway, it's nice when you get one that doesn't drip. Nonetheless, dripless
is *not* a sine qua non of a good pot in my book.

Michael