Burning Saw Dust in a Wood Stove

[Losos]

Hi
Being "murican I mostly lurk. That being said you can burn sawdust safely, maybe

What I do is put a 3in tube vertically in the center of the stove. Pack sawdust around it as tight as you can. Pull the tube out and light the hole. as low as you can. I generally just throw a match in. the sawdust will burn in a circle outwardly. Mine is about 24 in round and 18in high and last about 3 hours.

I'm on the road now but if your interested I will post some pics in a week or so.

If you just want to try it out. Take a gallon can. put a tube in it and pack sawdust around it. pull the tube and light. You'll see what I mean Nice little on the job heater

Dave

Welcome to the forum Dave,
That's an interesting idea, my wood burner is unique in that it has a door on the side, it's a very crude design (Most things in this part of Europe are) but it does give out a lot of heat once it gets going. I don't need to use sawdust having plenty of rubbish timber to burn at the moment so I put it on the compost, but the time may come when I want to burn it .

 

[les chicken]

I have had the R2 for a couple of years in my workshop, now on its second flue. Burning sawdust is no problem as long as you use it to start the fire and not top it up.
When the R2 is cold I fill it up to the flue and push my fist into the centre to make a hollow. Some paper or a firelighter in the hollow and close both vents halfway. This will burn for about an hour or so and then top up with logs or off cuts NOT sawdust or shavings.
If you put sawdust or shavings on a hot fire they will smother it but burn from the bottom. The trouble starts when the gasses ignite above the sawdust, usually results in the top being blown off or flames through the control vents.
So as long as you use sawdust or shavings when the fire is cold and light from the top there is no problems.

Les

PS speaking from experience.

 

[woodshavings]

Thanks Les,

I have now been using it and also found the top was lifted off a couple of times after topping it up with sawdust (in paper bags) on a hot fire bed- I wondered what caused it.

I have the vitreous flue - I hope it lasts more than a year!

Cheers, John

 

[Katomi woodsmith]

Hiya i mix my saw dust and the very fine dust collected by the dust extraction system
With coal and make bricks that I later burn on the wood burner.
I keep a bucket of shavings dust in a closed container that I use in the even of a liquid spill or to soak the rain that seep in under the garage

 

[Jacob]

Old thread but an ongoing topic!
I burn all my sawdust and shavings.
What you must not do is to throw them onto an already burning or smouldering fire as the airborne dust can explode dramatically.
When the fire is right out fill with sawdust and ignite. Wait until it is burnt right down before putting another load in, and relight.

 

[Phil Pascoe]

I pack mine in small cardboard boxes to burn it.

 

[Keith 66]

I had a big stove made out of an old air receiver, I used to fill it up with sawdust & shavings & ram it all down hard, leave or make a hole down the front & light that. Used to burn for hours.
The risk is that the fire will undercut the packed sawdust & you may get a cave in. That can lead to a flame out. When that happens the heat from the red hot embers will continue to pump smoke out. If it ignites you can get a flashover, this often happens if you open the door, if it suddenly takes a big intake or toke of fresh air it is about to ignite & can do so with some violence. Worst in my stove was when it shot a 18ft jet of flaming sawdust across the workshop which entailed some fast leaping about with buckets of water!

 

[Jacob]

I had a big stove made out of an old air receiver, I used to fill it up with sawdust & shavings & ram it all down hard, leave or make a hole down the front & light that. Used to burn for hours.
The risk is that the fire will undercut the packed sawdust & you may get a cave in. That can lead to a flame out. When that happens the heat from the red hot embers will continue to pump smoke out. If it ignites you can get a flashover, this often happens if you open the door, if it suddenly takes a big intake or toke of fresh air it is about to ignite & can do so with some violence. Worst in my stove was when it shot a 18ft jet of flaming sawdust across the workshop which entailed some fast leaping about with buckets of water!

Wrong shaped stove!
Mine was (have moved since) a Dowling Sumo and roughly pyramidical. These means that even when packed full there is enough air over the top of the pile for air to pass, so it will burn from the top, with no problems.
The heap is stable and won't collapse in any way.
Stove designers take note!

 

[Robbo3]

I've followed Phil P's tip & fill empty food boxes with dust & shavings to burn on the wood stove in the workshop.

 

[Keith 66]

Wrong shaped stove!
Stove designers take note!

Thats as may be but it was free & i was skint. The workshop was 1500sq ft & uninsulated so in the winter very cold. Summer too hot!
The air reciever stove was riveted steel 1/2" thick & stood 6ft high mounted vertically, door in the centre & ash pan door in the bottom. 8" dia steel chimney with damper. I cut two holes near the top & ran a long length of scrap stainless chimney liner flue in one that did one & a half full turns before it exited the other hole. A blower fan on one end gave a space heater effect. The stove was hungry but actually heated that workshop so was well worth doing. When burninng sawdust i never filled it more than about its diameter high ie up to the bottom of the main door. More exciting than the flame out incident was when one of my "mates" thought it would be a laugh to chuck an aerosol can of easy start into it when it was well alight.
The resulting explosion was very loud & caused flames to erupt from every door & the chimney.
The door never fitted that well after that!

 

[Jacob]

Thats as may be but it was free & i was skint. The workshop was 1500sq ft & uninsulated so in the winter very cold. Summer too hot!
The air reciever stove was riveted steel 1/2" thick & stood 6ft high mounted vertically, door in the centre & ash pan door in the bottom. 8" dia steel chimney with damper. I cut two holes near the top & ran a long length of scrap stainless chimney liner flue in one that did one & a half full turns before it exited the other hole. A blower fan on one end gave a space heater effect. The stove was hungry but actually heated that workshop so was well worth doing. When burninng sawdust i never filled it more than about its diameter high ie up to the bottom of the main door. More exciting than the flame out incident was when one of my "mates" thought it would be a laugh to chuck an aerosol can of easy start into it when it was well alight.
The resulting explosion was very loud & caused flames to erupt from every door & the chimney.
The door never fitted that well after that!

Sounds like a lucky escape!
Trouble with a vertical tank is that the burning area of the sawdust is limited to the small cross section of the tank, whereas a shape nearer to the natural shape of a heap of loose stuff (i.e. a pyramid or cone) gives a much bigger surface area, a faster burn (regulated with suitable controlled top air inlet) and no danger of the heap collapsing in on itself.
That's how it seemed to be with the Dowling Sumo, although I guess not designed with sawdust in mind.
If I was a welder I'd wonder about a design based on a cube shaped stove but tilted 45º to stand on one edge, or even both ways, to stand on one corner