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futurebird, on 17 May 2013 - 01:55 PM, said:

From my perspective of just having returned from Yixing........

Remember that China blocks Faceebook completely. I had no access to Facebook when there at all. Apparently there is a Chinese equivalent of Facebook that folks there frequent.... but it is all Chinese language. I'll see if I can get the url for that and post it. Might be useful.

As to the zisha potters there having an online presence........

I bet that some do.... but likely all in Chinese language. More than my experiences in Japan and South Korea I found that in Yixing I found very few folks who spoke any English at all. Less than I expected. So if you find them....... likely they speak only some dialect of Chinese. Search using the Chinese characters for Zisha clay tatehr than the roman type spelling. I believe this will maybe get you something .......... 紫砂工艺 .

From seeing the situation in Yixing (with the usual danger of generalizing in that everytrhing you say is wrong) I think there tends to be two general classes of potters working there. Those that are working their butts off making a somewhat basic living........ and likely who have little time (or money) for the Net. And those that are VERY successful and also have little time for the Net,.....because they have a HUGE market in their backyards.

That last part is an important point. There IS clearly a huge native market for zisha teapots (and other related items) happening right in the local community and within China itself. The economy was clearly booming. People were buying pots......and VERY many of them what WE in the West would consider very expensive functional pots. (Unless you consider something between $500 US and $1000 US average a usual price for a small -tiny really- teapot.) The top artists teapots were in the $10,000 to $20,000 US range.

So... there might be less need to "reach out" on the net to establish a presence relative to marketing for any of the potters there.

best,

.......................john

Chris Campbell, on 17 May 2013 - 11:51 AM, said:

Amen and Amen!

best,

.......................john

A tip or two for ya' on kiln building and design............

One of the common causes of cold floors on kilns revolves around the mistaken understanding that so many people have that "heat rises". That preception being some sort of a "law" comes from our experiential understanding of our lives....where we experience that HOT GASES rise (like in heated structures). Hot gases rise when suspended in colder gases. Heat energy....... not true.

This mis-understanding is a core concept that I deal with in my Kiln Design and Construction classes.

Heat energy ALWAYS moves from areas of higher concentration to areas of lower concentration. Basic law of thermodynamics. Entropy. Water flows downhill. (Yes... a heat pump can move heat energy seemingly "uphill",...... but that is a separate subject.)

If you want the kiln to fire as evenly as possible using as little fuel to accomplish that feat as possibe........ make sure you don't under-insulate the floor. Otherwise you'll have to adjust the heat DISTRIBUTION pattern in the unit to send more of the overall energy into the floor area than otehrwise necessary.... some of which to also be lost out of the underinsulated floor..... and costing you money in every firing.

So if you decide that the walls and roof structure of a kiln has to have a specific insulation value (heat loss in BTS/ Sq. Ft. / hr.) then the FLOOR should have the same level of insulation. (See * note below also) So if your walls are 9" of brickwork compoised of a 4 1/2" hard brick hot face layer, backed with a 4 1/2" insulating brick layer (of some specific use temp rating) then the floor should also have about this same rating overall.

This can be a little different due to the typical layout of floor bricks being set in the 2 1/2" high layer and the walls being in the 4 1/2" format..... but you CAN lay floors with the brick set in the same (or similar) configuration. The common choices to "match" up to a 9" wall section oftten comes to a decision between a 7 1/2" thick floor and a 10" thick floor. If you understand the insulating values of refractories, you can achieve the SAME insulating value (BTU / Sq. Ft / Hr. conductivity) out of a thinner floor wall section than the side wall structure using DIFFERENT materials........ so the thickness is actuall irrelevant.

The important concept is that the INSULATING value be similar.

The old Rhodes book showing so many 5" thick hardbrick floors in kilns is responsible for SO many kilns with cold bottoms it is amazing. This is something that I commonly end up fixing on a kiln when I am called in to troubleshoot some kiln firing issues.

And if you decide to use fiber in the floor area........ make sure not to compress the fiber too greatly (difficult in a load bearing situation). The more you compress the dead air spaces... the more the loss of insulating value. There is an optimum level of compression for fiber...... used in stuff like Z blocks. Best (easiest) to use "hard versions" of fiber for floors....like board forms.

best,

......................john

(*NOTE: Because there is typically less free air circulation across the cold face of the floor structure, technically the amount of heat energy disappated into the surrounding environment off the cold face is lower than on the vertical wall surfaces and off the roof or arch. So the BTU /Sq,. Ft. / Hr. loss values there is slightly less than the same construction in a wall or roof. But this factor is so small in the overall picture ...as to be inconsequential.)

OffCenter, on 17 May 2013 - 11:10 AM, said: