Stove Production in Korat in 1988-1999
Over the years I have visited a few charcoal burning kitchen stove factories. These are small things that you can set one pot on. They burn charcoal. In 1988 a large proportion of kitchens still used them. Even in 2026 a kitchen with a gas stove needing an extra “burner” might throw something on the charcoal stove. They are still used for several types of grilling หมูกระทะ is one. Its been called Korean Barbeque at times. There are restaurants that specialize in it and sometimes places that deliver burning stoves with all the fixings to your residence.
The factories have all employed over 10 people with many performing specialized jobs. I have seen two styles made, the USAID design built on an internal mold, and the standard design built inside an external mold. In Korat they used the external mold. The internal mold is used in Khon Kaen. There are likely factories in most populous provinces.
The clay is a local orange clay and it is highly tempered with partially burnt rice hull ash. The rice hulls are used as fuel for the firing so there is ample supply and the carbonized but not fully burnt ash that gets included in the body just adds a bit of fuel to stack and burns out leaving voids, slowing the progression of thermal shock induced cracks.
The clay is slaked and then mixed and dried with rice hull ash. The mix is slightly thixotropic. This is also true of Baan Maaw clay and I attribute it to potassium salts in the rice hull ash. Although small percentage wise it does not take much to change rheology of clay and water mixes. The mixers were built with surplus motor vehicle motors and transmissions using old differentials from truck and car rear axles. The mixers in these factories are vertical mixers with a central slow speed blade. Generally there is an outlet door at the bottom that is opened after the mix is sufficiently mixed.
The clay is pressed into the external mold and smoothed and a ridge for the grate is added. The object is popped out of the mold, a hole added to the bottom for air and three lozenge shapes are cut from the rim forming a tripod for a wok or other pot to sit on.
After drying the stove internals are stacked rim down in a large scove with brick sides. The top is covered with pierced ceramic disks to hold coal off the floor of the stove and the spaces between the stoves are filled with rice hulls. It is lit and allowed to burn down. I do not know how many days this takes.
The fired stove interiors are then packed into metal containers made of steel “tin” can misprints and excess and the space between the interior and the can is filled and tamped with a mix of ash, cement and maybe some clay and sand. The top of the tamped mix is finished with a mix containing more cement. Given how they look I expect a similar finishing technique is used in the Baan Maaw Mahasarakham stove manufacture.