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Brick kilns are designed to finish bricks and produce charcoal or other heat-treated materials. A brick kiln should be constructed to withstand high heat temperatures and have a strong resistance to outdoor elements. There are various designs for brick kilns, the most common types being the beehive model and the slope model.
The beehive models are circular in diameter and covered by a dome roof. A brick kiln designed in the beehive fashion is generally constructed using standard brick. These models are built entirely above the ground, and they contain air inlets around the perimeter at ground level.
Beehive models are fairly easy to construct and require no concrete foundations or complex building materials. A brick kiln designed in this manner is typically durable and may last for several years without requiring any repairs. A fair amount of soil manipulation and landscaping may be required before beginning the construction of beehives kilns.
A slope model brick kiln is similar in shape to a beehive kiln. Slope model kilns have dome shaped covers, but the sides are generally immersed underground so only the roof is exposed. Ignition occurs at the top of the dome, and there is usually only one main air inlet, underground at the center of the kiln.
Slope kilns are usually built between hills or slopes that surround the sides of the kiln. These models also contain several smokestacks to help control ventilation. Due to the usage of excess soil, slope models require fewer bricks for construction, but the smoke stacks require the installation of a steel band in the dome. These bands tend to corrode within a couple of years and will require regular maintenance.
Rich and moist soil is usually a necessary foundation for slope kilns. Clay or sandy soil may cause the kiln to crack and eventually collapse. If the surrounding soil is suitable, construction should be fairly easy.
Both kilns operate using wood-burning fuel. They both perform the same basic functions, heating bricks at extremely high temperatures. Once the bricks are cooked for several hours, they become stronger and more durable. Bricks or other finished materials are then moved to a cooling side of the kiln where they are finished and removed.
A brick kiln can reach dangerously high temperatures and caution should be used when operating or when in the vicinity of the structure. A well-designed kiln can safely last for many years and be relatively low maintenance. Kilns generally require close supervision, however.
This article makes me really curious how hard it would be to make my own kiln to fire bricks in at home. It sounds like the kinds of kilns described here, bee hive style and slope style, are smaller designs.
I could be wrong, but somehow I doubt that brick manufacturers fire bricks in kilns like this. Wouldn't they make bricks in some huge factory somewhere that can fire the bricks assembly line style? That seems more efficient.
Anyway, back to my original reason for posting. Brick kilns seem much more affordable than regular pottery kilns (which cost a small fortune), so I wonder if you could make a brick kiln and use it for other kinds of pottery as well?
I don't see why you wouldn't be able to, except maybe that some kinds of fine pottery like porcelain requires higher temperatures. Has anybody tried it?
@seHiro - Both of the standard brick kiln styles that the article discusses, slope style and bee hive style, use bricks in their own construction. One has more metal than the other, but they both need bricks.
To my knowledge, there isn't a modern brick kiln style that does not use bricks in its own construction. It is kind of funny, now that you make me think about it! Bricks are just the most readily available, convenient material to use, I guess.
In response to your "chicken or the egg, kiln or the brick" question, I can give you an educated guess based on my background in pottery: the first bricks were probably fired like the first pots, directly in the campfire.
Once people figured out that ovens made of bricks or pottery cooked hotter inside than baking over the campfire, they likely stuck bricks inside just like they put food in there, and so harder and higher-quality bricks were gradually invented.
Isn't it interesting that the brick kiln design is made out of bricks?
I guess there's no reason not to make it out of bricks -- you know they'll hold up to the heat required to make the bricks being fired inside hard, after all -- but it seems goofy in a "chicken or the egg" kind of way. Which came first, the bricks or the brick-walled kiln they were made in?
What other materials are brick firing kilns made out of, anyway? There must have been a different material originally, or nobody would have been able to fire the bricks required to build one of the newer kilns.