Most carpenters and woodworkers find themselves with the problem of disposing of all the sawdust they create when performing their craft. There are lots of creative solutions to this problem, such as adding it compost, using it as groundcover in a garden, adding it as filler in a composting toilet, or pressing it into bricks to burn in a stove. All of these have their uses, but involve either transporting the sawdust somewhere or performing some intermediate step to process it. [Greenhill Forge] wanted to make more direct use of it so he built this stove which can burn the sawdust directly and which provides enough heat for his woodshop.
The design is based on one which is somewhat common in Japan and involves building a vessel with a central tube for airflow, with the sawdust packed around it. The tube is made from a hardware cloth or screen to allow air to reach the sawdust. The fire is lit from the top, closed, and then allowed to burn through the stack. [Greenhill Forge] welded the entire stove from various pieces of sheet metal and bar stock, with a glass plate at the top of the stove to close off the fire and a baffle to control the airflow and rate of burn.
Initially, [Greenhill Forge] thought that the fire would burn from the top down, but this turned out to create a smoldery, messy fire instead of a hot, clean burn. Eventually, though, an ember fell down to the bottom and let the stack burn from the top up, and then it started generating serious heat. He estimates that with around 5 kg of sawdust burning for three hours that it’s about equivalent to a 6 kW stove. While a woodworker might not have enough sawdust to run this stove every day, it could be good to have on hand to use once every few weeks when the sawdust builds up enough. [Greenhill Forge] has been hard at work building unique wood burning stoves lately, like this one we recently featured which generates and then uses charcoal as fuel.
