Stove Production in Korat in 1988-1999

Baan Maaw village, Meuang Mahasarakham District, Mahasarakham province, Thailand kingdom Sometimes this village is refered to as Baan Pan Maaw บ้านปั่นหม้อ, rather than Pot Village this is Village [where] Pots [are] Formed. Pan ปั่น means spun. Its odd as the pots are mostly handbuilt. I wonder, but do not know if the longer name is newer, or not really used. 

Maaw (หม้อ), means “pot” as in pottery. Baan (บ้าน) means house. A village is a muu baan (หมู่บ้าน). The first part of this, “muu” (หมู่) usually refers to a group of houses or a village. Mail addresses often are associated with a muu, such as muu 4 Dankwian. That is a group of houses in an amphoe or district or in a muubaan. These muu are associated with how a mailman does his job. Its easy to be confused. 
Thailand
Provinces – Changwat(
Ampoe 
Tambon
Muubaan
Chumchom
Its more complicated than that. Large cities within provinces are generally referred to as Amphoe Mueang
maybe this needs clarification or deletion. 
But Baan Maaw is a village  with a clear  grouping away from other villages. The pots that they made were almost exclusively 8 liter or so, porous water cooling jars. They all have a stipled band that appears decorative just above the belly, the widest part, a broad rim and a lid. They are bonfire fired to about 760˚C or 1400˚F. This temperature is a guess based on the look of the fire. It could be as much 200 degrees fahrenheit lower. The pots are unglazed, although more recently (2014) some were being coated in tree resin when hot for a black and shiny finish, and some have been being treated with the Dankwian Antique Finish technique (discussed in the section on Dankwian Village). 
The clay, last time I. saw it being delivered to the village came by 2 wheel cart and was in 25cm cubes, (about 10 inches). It was cut from the ground wet with a flat shovel. I did not watch it being prepared. It is a sticky clay, and from the ground a light grey color. It bears no resemblance to Dankwian clay other than being fairly sticky. 
The clay is mixed with grog, or if you prefer chamotte, made with a novel technique. The grog, the only time I saw the beginning of the production, was made with mud from the bottom of the local reservoir Loeng Pan Maaw เลิงปั้นหม้อ . Loeng เลิง means marsh or swamp. The Loeng near Baan Maaw I believe was excavated to get fill and create a bigger reservoir. It appears to be much larger now (2014) than I remember it being in 1989. The mud is mixed with copious amounts of rice hulls to make ~ 15 centimeter balls, roughly six inches. The balls have a 2.5 cm diameter hole that goes in towards the center.  This creates an object that burns like very low grade charcoal briquettes.
Usually these are piled canonball style over some firewood in a 6 by six grid and about 5 layers high.. They are burned to a temperature similar to the temperature at which the pots are fired but probably a little lower. There is so little clay in these that they can easily be crushed with a persons weight and a shoe. It takes at least a few hours to burn and is not carefully attended as it does. 
Rice hulls are near perfect for this use. They are agricultural waste. They were traditionally burned to eliminate pests. While they can be added to soil, they are slow to decompose and light so they do not stay in place in flooded rice fields. Partially burned rice hull is a more suitable soil ammendment in rice fields. Consequently this use if effectively carbon neutral. They would likely be burned anyways. 
Rice hull ash is almost entirely silica. The two analyses I have show it as 96% silica, 1% alumina and less than 2% alkali metal and alkaline earths. The alkali metals and alkaline earths are soluble and some will end up in solution in the clay and alter the working properties. But this low amount is not enough to cause big problems. I believe that it at least contributes to the thixotropic feel of Baan Maaw clay. Thixatropy is the property of a material where with stirring or manipulation it becomes more fluid or flexible. 
Silica can be added to a clay in large percents, and quartz sand, another way to get silica, is sometimes added to clays to replace or instead of grog. But where the silica in quartz is crystyalline, the silica in rice hulls is amporphous. Quartz rapidly increases in size just above red heat, something potters call Quartz Inversion, and the size change can cause cracking in pottery. Amorphous silica does not exhibit this phase change, and therefore is safer as an addition to clay. It does not cause cracks. 
The silt that holds the rice hull balls together fires into a very porous structure with lots of sharp texture. That texture holds onto clay well. The quality of grog is related to how open the texture is and how sharp. Better grog makes stronger clay. Rounded smooth particals weaken a clay body both in the raw and fired states. I believe that this grog significantly adds to the amazing strength of the raw clay pots.It also, do to its open porous nature, makes fast firing easier to accomplish without explosions. 
The pots are started with a rolled cylinder process achieved with a stick about the diameter of a broom stick. The cylinders, maybe about 18 inches tall are place on damp fabric on one end and formed slightly by a hand placed on the inside in opposition to one on the outside. The pot is turned on the damp fabric. 
After this initial forming and a small amount of drying, it is placed on a stump and paddled into a larger form. The rim is thrown, not by spinning the pot but by walking around the pot quickly. The body of the pot still has a hole in the bottom from the cylinder rolling process. After setting to dry a little more the bottom is paddled closed. The form is then placed inside an old pot shoulder section, it having an appropriate curve and allowed to dry a little more. The shape is finished by paddling one or two more times. 
During the first part of drying, I think of it as the wet stage, as the water dries the particles of clay move closer together and the form shrinks. As this stage ends the clay gets much less maleable. In English people call this “leather hard”. This appears to be because at this stage it can be tooled like leather.But at this stage small voids form. They dissapear as the clay vitrifies, but the water that used to fill up these voids dries out. Its my theory that paddling removes some of these voids and also aligns flat clay platelets parallel to the surface of the pot. I have no great evidence of this.But the quality of the grog, and the paddling in Baan Maaw  Mahasarakham and other such potteries results in greenware (unfired ware) that is remarkably strong. The fired was is quite strong too, especially considering the firing temperature. 

Firing takes place in the afternoon when the sun is strong and the temperature hot. I believe that this is to reduce explosions caused by hygroscopically held water. I have never seen an exploded pot in Baan Maaw. I have only witness firings during the hot season.

The pots are fired “Bonfire” style. There is a lot of variation in bonfire firings but the firings here resemble some in other countries. There is a bed of thin sticks roughly 1 -2 inches in diameter placed up from the ground on roughly 4 inch tall fired ceramic props. This allows air under the bed early in the firing. Two layers of pots are placed on the stick bed. The first is placed rim down with six pots on each side of the square stack. So the grid of the first layer is 6X6 or 36 pots. The second layer has pots placed with rims up at about 60 degrees from directly vertical in a 5X5 grid for 25 pots. Lids are placed between the pots.The total stack holds about 61 pots. 

The stack is covered by rice straw and lit on fire. It all is engulfed in flame in the first few minutes. After a few minutes a second layer of straw is added. The access to air around the outside is managed and the outside pots are checked by color for how well fired they are. Additional straw is added until no longer necessary. The entire firing takes about 1 hour.

There are products other than the water jars that are produced in the village. One is rice cooking pots. These are small earthenware vessels meant for a few uses on top of a charcoal stove. Charcoal stoves are also produced in the village. There is a small amount of sculpture produced in the village. 

The charcoal stove design is an outgrowth of a USAID development project from before 1988. At the time a vast amount of wood was being turned into charcoal for day to day cooking in the villages. Besides being an agent of deforestation, pollution and environmental damage it was an expensive way to cook. The stoves were very inefficient. 

A newer project to produce stoves resulted in the Tao Mahasethee เตามหาเศรษฐี stove or “Billionaire Stove”. Because of the name when they show up in the press they are immediately ridiculed. Online posts about charcoal stoves in Thailand often ignore the earlier work.  ( see Stove Production in Korat)

What they make
Process,
progressive paddling and strength
Firing Rice Straw
Small wood
Stands

materials
Grog Balls

Thixotropy?

Market shift