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Primitive Technology: Building a Tall, Natural Draft Furnace

draft furnace

He builds a tall, natural draft furnace to test how high he can get the temperature to go without a bellows. It's a white-hot success.

Our man in North Queensland, Australia, is definitely the strong, silent type. He's also the endlessly creative and experimental type, as he continues to increase his evolution of primitive technology projects. This time he built a natural draft furnace.

It looks like a relatively easy build for him. It's basically a tall clay chimney, although his expertise in mixing and forming clay with his bare hands continues to impress and mesmerize.

But his reason for this particular project was to see if he could create a furnace that could achieve very high temperatures without the use of a bellows. It looks like he did it.

While he doesn't speak in any of his videos, he does provide extensive explanatory text. He also offers the option of closed caption text to go along with what you see on the video.

"The temperature of hot objects can be visually estimated from their incandescence," he says. "After about an hour, the light coming out of the tuyere was high-yellow to white-hot indicating a temperature of at about 1200 c. Colour temperature charts vary but white hot is usually given to be at least 1200 degrees Celsius. It was uncomfortable to stare into the tuyere and doing so left an after-image when looking away, indicating the strength of its brightness."

As he moves closer to producing metallurgy, a furnace like this would be useful, as it would cut down on labor. He wouldn't have to rely on pumping a bellows to get the temperature up.

He could smelt iron ore and copper with such a furnace.

One can only wonder and eagerly anticipate what his project in metallurgy will produce once he's ready to begin.

Like what you see here? You can read more great articles by David Smith at his Facebook page, Stumpjack Outdoors.



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Primitive Technology: Building a Tall, Natural Draft Furnace