Recycling Sawdust

[HarveyWildes]

Any good ideas for recycling sawdust?  We've used sawdust instead of leaves for composting for many years, but this year we decided not to compost, so I'm looking for other ideas.  I live on two acres in Colorado, with only about 2000 ft2 of sod.  The rest is field grass, and the overall organic content is pretty low.  What about just spreading the sawdust onto the grass?

 

[afish]

Maybe if there is a pellet maker near by, if its all hardwood shavings.  Im not sure if they will take it if it has glue or resin in it from particle/mdf/ply. 

 

[Ron B]

I would just spread it out over the field grass. Some types of sawdust tend to be acidic.    I do not know the soil ph in Colorado, but farmers will spread field lime on a field  to adjust the ph to a more neutral zone. If you have pine trees, they tend to like acidic soil so don't lime around those or other evergreens.  When I built my house (DIY) I pitched the drywall scraps out the back door.  Then winter hit.  The next spring the paper came off easily, and I just spread the drywall gypsum around my yard  to help the soil. 

 

[Peter Kelly]

Certain woods contain natural herbicides (black walnut) so I'd be careful of what you spread around the property. If you've got a wood stove, it's easy enough to compress wood chips and dust into briquettes with a homemade press and some kerosene or just water:https://www.hunker.com/12567869/how-to-do-it-yourself-sawdust-briquettes

 

[Bob D.]

Matthias tried burning it.

 

[squall_line]

I'm glad he at least loaded the finer dust into bags and boxes and loaded it that way.  When I saw him shoveling that stuff, I was waiting for the inevitable dust explosion and the loss of one or both eyebrows.  [eek]

 

[RobS888]

We empty our collection barrels into XL paper lunch bags (we cut a bleach jug to be a little more than the bags hold.) and staple the tops. We fill paper lawn bags with them for storage, I imagine the moisture moves in and out of the paper bags as needed instead of going moldy, then we burn the lunch bags in a sealed fireplace insert. It takes my wife and I about 30 min to fill bags from a 55 gallon barrel. Mostly from her lathe. We have 8 or 10 yard bags each year to burn.

They burn well.

 

[Peter_C]

Having used a wood stove as our only heat source, I can say I wouldn't put saw dust into my stove. Too much creosote possibility as it burns and embeds itself into flue maybe only partially burned. Ever seen a flue fire? The flames shooting 8+ feet out the top of a chimney is impressive. Yes you can clean more, but with some stoves like my Quadra Fire are a pain to clean and required the stove to be cold, meaning no heat for a day or more. If the stove has a catalytic converter, dust could damage the cat. Burning hot to clean the flue only does so much. I would like to think I had heating with my own stove down to a science.

If I didn't cut a lot of plastic I would just spread it around the yard, while wearing a mask and staying upwind. 2 acres is a decent yard too

 

[RobS888]

We only have about 50 fires/year so not experts, but how do you know sawdust doesn't burn well or fully combust? Not starting a fight, but your comment and our experience don't jibe.

Most of our sawdust is hardwood. Our Jotul insert is a sealed unit with stainless steel pipe all the way to the top of the chimney with vermiculite insulation filling the rest of the chimney. We have it cleaned every 2 years and have never had much build up.

Dust itself can be explosive, grain silos can explode from corn dust. so opening a fire and throwing sawdust on it could be a problem that doesn't extend to a bag of dust. I think the packaging is the important point here.

it seems to burn fast and hot.

 

[Peter_C]

Want to run a scientific test? (My saw dust has plastic in it, so no burn test by me.) Start a fire outside with saw dust and see how much rises into the air. Everything going into the air would go up the flue which is bad. I know for a fact leaves and pine needles are horrible for wood stoves as they fly really well.

Read this thread, then come back and tell me there are no issues with burning sawdust in a wood stove.https://woodweb.com/knowledge_base/Burning_Sawdust_in_a_Wood_Stove.html

 

[RobS888]

I followed the link and read the anecdotes, but can't see any that are at all close to what I do, most if not all are detailing airborne dust exploding. Could you quote the one that is applicable please?

To be clear, after filling and stapling the bags there is no airborne dust in our case. The fireplace insert is in the house, so no dust from woodworking.

To be scientific, the results need to be reproducible and an outside fire doesn't sound like that. You could have wind affecting the fire outside whereas in the Jutol, there is a small inlet in the bottom that lets in outside air in a controlled manner.

I Just can't see how an open fire in a wood-shop is comparable to bags of dust in a sealed fireplace insert. Aren't pellets compressed dust as well.

Anything on dust causing more creosote would be appreciated as well.

 

[Peter_C]

Rob, please feel free to click here for further research.

This is a good visual reference of a sawdust bomb. Do as you want...it's your house.

 

[Sparktrician]

Any good ideas for recycling sawdust?  We've used sawdust instead of leaves for composting for many years, but this year we decided not to compost, so I'm looking for other ideas.  I live on two acres in Colorado, with only about 2000 ft2 of sod.  The rest is field grass, and the overall organic content is pretty low.  What about just spreading the sawdust onto the grass?

If it's hardwood sawdust, find a company that makes wood brick fuel to buy it.  [smile]  OTOH, buy a brick press and put your sawdust to work in your own place.

 

[CeeJay]

We add it to our compost. Makes for a nice dry mix.

Sent from my iPhone using Tapatalk

 

[RobS888]

Rob, please feel free to click here for further research.

This is a good visual reference of a sawdust bomb. Do as you want...it's your house.

I followed you link and the second text link after the videos says:
"Dust explosions can occur where any dispersed powdered combustible material is present in high-enough concentrations in the atmosphere or other oxidizing gaseous medium, such as pure oxygen."

I don't know how to get you to see that the state of the sawdust matters. If it is airborne it can explode. A pile, a bag, a brick, a pellet. is just cellulose fibers burning.

Lets agree that, to you, sawdust = explosions and leave it at that.

 

[Peter_C]

From the link below. "This exact scenario happened to me once with a Jotul and that was enough for me to change burning habits. In my case it was some damp maple wood. The kindling started normally and the maple started to burn with the door slightly ajar. I got impatient and closed the door with the air damper all the way open. Came back a couple minutes later and the flame had gone out, stove full of smoke. I foolishly cracked the ash pan door open and as soon as a flame appeared - Kawhumfph! The smoke (which is unburnt wood gases) ignited and smoke blew out of every orifice and pipe joint."https://www.hearth.com/talk/threads/wood-stove-exploded.173123/

My fear would be putting the bag of saw dust on the fire, paper burns off smothering the fire, causing heavy smoke, then experiencing a backdraft that kicks saw dust up into the air from the THUMP. Yes a dust bomb could be created in the wood stove, inside the house.

Rob, you previously asked which post I referred to regarding the link I posted a few posts above. Here is the first quote:
"I use to burn sawdust the same way 25 years ago. One day I filled my shop with panels that I had just finished and stoked up the stove with sawdust just like you describe. Just as I started to walk out the door the stove door burst open and burning sawdust flew 40 feet to the other side of the shop. And that was the end of my sawdust burning. I have done some dumb things in my day and that one was right at the top of the list. Sawdust doesn't just burn it explodes."

Another from the same link: "Be careful with this. I had a friend who was doing some serious sanding in his small steel Craftsman shed/shop and when he opened his wood stove and tossed a handful of sawdust into it, the shed blew-up! He was found unconscious and only slightly injured about 50' from his shop! Yes, his situation was unique, but I learned a lesson about dust and fire that day. Oddly enough, the local grain elevator had a major fire within weeks of this mishap with far more expensive results."

So yes I do consider dust and fire explosive as do many others. Maybe because as a teenager I worked in a very old late 1800's flour mill, we only used as a grain elevator, wherein during harvest season I was trained to try to keep the mill from exploding, including from spontaneous combustion, leads me to be afraid. A wood worker bought it to use as a shop and of no surprise, it burned down.

Sorry if I come across rough, I am not an eloquent writer. Just don't want anyone getting hurt or damaging their home.

 

[Tom the Remodeler]

Not picking sides here, but I would point out to Peter that you are posting links to anecdotal stories from people throwing loose sawdust into wood burning stoves and suffering the consequences. It would appear that Rob is prepping his sawdust in more of a "log" format, and is asking if you have scientific (not anecdotal) data to support the claim that burning non-airborne sawdust is dangerous.

I think that both of you are well meaning, but are speaking past each other a bit here.

In Rob's defense, burning sawdust is a well-established practice in industry, and I've been to many woodworking shops with briquetting machines connected to their dust collectors for exactly this purpose.

That being said, I can see Peter's point regarding "loose" sawdust, and the concern around burning sawdust not prepared in a engineered briquetting machine.

I suspect that you can both agree that burning airborne sawdust is dangerous, and that burning briquetted sawdust with the proper safeguards is safe, and that there is a liminal space in between where you disagree, or at least need to more clearly define your parameters of disagreement.

 

[Cheese]

I usually compost the stuff because of the large quantity I get from the cyclone and that works well.

However, for the last couple of years I've emptied the cyclone more often and with that smaller quantity of saw dust, I've just spread a thin layer on grassy areas and it seems to disappear within a week or two.
https://www.thriftyfun.com/Using-Sawdust-in-Your-Garden.html

 

[Peter_C]

Not picking sides here, but I would point out to Peter that you are posting links to anecdotal stories from people throwing loose sawdust into wood burning stoves and suffering the consequences. It would appear that Rob is prepping his sawdust in more of a "log" format, and is asking if you have scientific (not anecdotal) data to support the claim that burning non-airborne sawdust is dangerous.

I prefer to learn from others peoples mistakes. Log format is completely different than putting loose saw dust in a bag where the bag can burn away in say 45 seconds leaving loose saw dust. Any kind of wood stove THUMP (Blast of air) can now send that loose saw dust airborne. Hypothetical yes, possible yes.

When did it become my job to prove beyond a reasonable doubt that a serious event could occur? Reality is I don't want to be proven right because that would mean someone was put into serious danger, unless conducting a Myth Busters type scientific study standing behind a blast shield.

In Rob's defense, burning sawdust is a well-established practice in industry, and I've been to many woodworking shops with briquetting machines connected to their dust collectors for exactly this purpose.

I'd agree briquettes should be considered safe. At home though compressing into bricks has little ROI, especially when one can go the forest and cut a truck load of wood in the same time frame.

That being said, I can see Peter's point regarding "loose" sawdust, and the concern around burning sawdust not prepared in a engineered briquetting machine.

After the bag burns off one is left with loose saw dust...see video below.

Now imagine inside the stove the air continuously rising as the bag collapses, causing the saw dust to become airborne.
Now imagine the air rising as the bag collapses, causing the saw dust to become airborne.=187

I suspect that you can both agree that burning airborne sawdust is dangerous, and that burning briquetted sawdust with the proper safeguards is safe, and that there is a liminal space in between where you disagree, or at least need to more clearly define your parameters of disagreement.

I've put more effort into this thread than it is worth. We live in a country with freedoms to do as one wants...mostly. Go for it!

 

[Packard]

Mix it in with molten paraffin wax to make your own fire starter logs.  Pour into empty milk cartons to get the shape.  A friend cut off the container before lighting, but I don't think that is really necessary.

Or buy a hamster and use it for bedding and litter boxes.  (But wood shavings work better.)