How to Burn Sawdust Cleanly

8,343

25

2

Introduction: How to Burn Sawdust Cleanly

About: I'm an Engineer, who originally inherited the family business (Thanks Dad (RIP JC Taylor, 1938-2011)) after working in it for 25 years, designing and building scientific instruments. In 2013, I was head-hun…

Here's a brief 'ible on burning sawdust. If you've ever tried to burn a pile of sawdust, you'll soon find a very smoky mess on your hands - and lots of unburned sawdust at the end of it.

For reasons which I can't quite fathom this method is also known as "The Boy Scout Candle". It will yield a very clean flame, because the operation is by "pyrolysis in excess air". The wood is strongly heated by the flame front, liberating burning gases into the flame. Convection through the stack forces lots of air into the reaction, and there is very little smoke, if any.

The example shown here burns for only about 15 minutes. The burn will scale up, but if you are very interested in advanced combustion, take a look for projects on "TLUD gasifiers"

Step 1: Equipment.

All you need for this demonstration version is

  1. A charcoal starter,
  2. Sawdust, or planer shavings
  3. A "packing tube" - I used a piece of 1.5", 38mm plastic tube, because it was what I had.

Step 2: Method.

Place the packing tube in the centre of the charcoal starter

Pack sawdust fairly tightly around the OUTSIDE of the tube.

Withdraw the tube slowly. I find a twisting action helps. You are aiming to leave a well defined core to the pack, with clear air holes at the base for the fresh air.

Step 3: Lighting

Well, you can cheat like me and use a blowtorch, or you can do it with some tissues at the bottom of the starter. If the wood is dry, you won't need any accelerant at all.

Step 4: More Work.

Experiment with scaling this up to a bigger unit. I'd love to try a 5 gallon metal bucket, because the demo version doesn't burn too long.

The flame is pretty clean, and you can cook on it.

Outside Contest

Participated in the
Outside Contest

Be the First to Share

    Recommendations

    • The 1000th Contest

      The 1000th Contest
    • Battery Powered Contest

      Battery Powered Contest
    • Remix Contest

      Remix Contest

    2 Discussions

    1
    gungajin
    gungajin

    11 months ago on Step 4

    Well, the bigger version would be a sawdust/woodchip oven. I had one of those in the early 80's and heated 80 square meters living space solely with this oven, in winter temperatures of minus 20 celsius. Was about 1.2 m high with a diameter of around 40 cm. I packed fine woodchips and sawdust directly into the oven, around a pole of roughly 60-70 mm diameter. It would burn for 8-10 hours. With maximum airflow, it would get so hot that the metal turned glowing orange. It's a brilliant solution if you have a lot of wood waste and yes, it can be made to burn very cleanly.
    I'm planning to build one for heating a wood steambox.

    0
    BROOKSY-1
    BROOKSY-1

    Reply 9 months ago

    Hi, do recall the model or manufacturer of the unit? Or perhaps some direction besides Google?
    Thank you.