Sawdust Log

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mtarbert

Minister of Fire
Feb 23, 2006
548
Maryland
I'm thinking about making a mold to turn sawdust into logs. I would make a mold out of thick walled pipe and use a 27 ton log splitter for compression. Does anyone know how lond the dust would need to be under compression before it solidifies? I would be using coarse sawdust from a saw mill.
Thanks,
Mike
 
the stuff that self-adheres from what I understand typically has about 150 tons of force applied to it. those sawdust-brick products (ala biobricks, woodbrickfuel, etc) typically use the RUF Gmbh. briquetting machine which does it in 2 stages I believe. at those pressures lignin liquifies and turns into a glue. otherwise you have to use some kind of binder/glue like wax.
 
If memory serves me correctly some folks have tried this in the past and have not had much luck getting the sawdust to stick together.
 
It makes my dad sick to see me dump my sawdust and bark pieces into our brush burning pit. He wants me to bag it and burn it in my boiler.
I can't see it being worth the effort. I'm jamming 12 cord into my wood room, and don't need dozens of bags of bark and dust in there, too.
Not enough BTU's per cubic foot, compared to some split maple or yellow birch (or even pine, for that matter!).
I will admit that the brush pile, patiently awaiting for some damp fall days before we light it up, is getting a bit big - probably half a cord (by volume) of maple sawdust.
Do any of you burn sawdust in your stove?
Do you save the bark that falls off and burn it, or just chuck it?
I can see saving the bark for my firepit, but the dust just smothers out the flames.
 
I turn a small amount of sawdust into fire starters. Using an old pan, I heat the wax (usually discarded candles) on the old shop stove (I wouldn't be doing this on some fancy stove, it makes a mess if you drip). Take a can (tin) and load up sawdust, pour wax on top, mix well and fold out into pan. Then weight it down and wait till it cools. Break into chunks, it works pretty darn good if you have a mix of larger and smaller chips (like from a chop saw or table saw).

Yeah, I was bored one cold winter day out in the shop. Made enough in about an hour to last two seasons.
 
maplewood said:
It makes my dad sick to see me dump my sawdust and bark pieces into our brush burning pit. He wants me to bag it and burn it in my boiler.
I can't see it being worth the effort. I'm jamming 12 cord into my wood room, and don't need dozens of bags of bark and dust in there, too.
Not enough BTU's per cubic foot, compared to some split maple or yellow birch (or even pine, for that matter!).
I will admit that the brush pile, patiently awaiting for some damp fall days before we light it up, is getting a bit big - probably half a cord (by volume) of maple sawdust.
Do any of you burn sawdust in your stove?
Do you save the bark that falls off and burn it, or just chuck it?
I can see saving the bark for my firepit, but the dust just smothers out the flames.

I've got plenty of good wood . . . and a whole buch of chunks, punks and uglies (short pieces, wood that is a bit punky and wood that is gnarly, twisted, etc.) in a pile . . . no need or patience to store and burn bark and sawdust.

Since I do most of my bucking in the woods sawdust isn't much of an issue . . . I will paw through some of the splitter trash and pull out the larger pieces and bag it for kindling . . . the rest of the mess (and anybark that comes off) is dumped in the woods near my house . . . where it will eventually become tree food for the trees growing there.
 
well the sawdust is actually excellent for sawdust toilets ;) but if you use a flushie it is useless, but those that compost their own "doo doos" are very happy with sawdust, compost for 1-2 years and you have the best soil ever, and you don't add to the "pollution" that flushies bring.

just have to sift the big scraps out and keep the sawdust under a tarp, fill a bucket as needed.

more info here:
Humanure Handbook
Loveable Loo

This stuff is usually of most interest for those that lives off-grid, but more people should use it, you can actually use it in the cities if you have your own garden, the composting doesn't smell and neighboors wont even know it is there unless you tell them. (don't tell them though).
 
Jags said:
I turn a small amount of sawdust into fire starters. Using an old pan, I heat the wax (usually discarded candles) on the old shop stove (I wouldn't be doing this on some fancy stove, it makes a mess if you drip). Take a can (tin) and load up sawdust, pour wax on top, mix well and fold out into pan. Then weight it down and wait till it cools. Break into chunks, it works pretty darn good if you have a mix of larger and smaller chips (like from a chop saw or table saw).

Yeah, I was bored one cold winter day out in the shop. Made enough in about an hour to last two seasons.

+1...although we do a "commercial" version of this. My wife used to make candles but no longer and had a lot of leftover wax. We just went out a got a bag of cedar chips from WalMart (hampster bedding) and a box of Dixie cups. Fill each cup with chips, melt the wax and pour enough into each cup to solidify the chips. We make about 2 dozen at a time and then they store very nicely for our fire starters. No more making kindling!
 
maplewood said:
Do any of you burn sawdust in your stove?
Do you save the bark that falls off and burn it, or just chuck it?
I can see saving the bark for my firepit, but the dust just smothers out the flames.

I work up my wood in two areas. I cut and stack all my green wood out in a back field, but most of my standing dead and lumber scraps I buck up in my driveway in small batches. After a few days or weeks in the sun, I move the dry firewood into the barn. The chips and dust on the asphalt are fully dry, so I scoop them up with a snow shovel and brown-bag them, maybe about 6" full. So they become loose-pack "bricks" of about 6"x6"x12". Since I have to clean up anyway, I figure why throw it away?

I'll toss a bag on top of a load of kindling when starting a fire, or along with a few splits when I'm reloading. As I watch the fire, it's interesting to see that as the bag burns aways the chips don't all just collapse, but they ignite and fall down in small clumps and even individually, not what I'd expect. Kind of fun to watch, like burning a load of dry pine cones. Anyway, it make it easy to choose paper over plastic at the grocery store.
 
maplewood said:
It makes my dad sick to see me dump my sawdust and bark pieces into our brush burning pit. He wants me to bag it and burn it in my boiler.

Do any of you burn sawdust in your stove?
Do you save the bark that falls off and burn it, or just chuck it?
I can see saving the bark for my firepit, but the dust just smothers out the flames.

Bark and sawdust have the same btu rating per pound as the wood it came from. I burn bark and sawdust when I can. A tarp or 4'x8' of plywood at the splitter makes for easy clean-up at the splitter. (I used to burn slab wood and have a "station" where I cut the slabs to length and my sawdust would pile up for me. Otherwise I don't mess with dust) The problem is storage if you only burn during the winter months. Moisture in bark and sawdust robs btu's and so your fuel cannot be as effectively used. Bark stacks easily enough (if stacked against a stack of bonafide firewood-preferably seasoned already as the bark would impedeseasoning of green wood) and works well in the "shoulder seasons." If the sawdust is dry it will fit into paper grocery sacks if you can find a store that still offers them. Either way the bark and saw dust have to be protected from moisture.
 
love the "Bark and sawdust have the same btu rating per pound as the wood it came from" statement but can u qualify it? this would make great fodder in the pellet forum where different pellets are deemed good or bad from opinions from experience
 
Cave2k said:
If the sawdust is dry it will fit into paper grocery sacks if you can find a store that still offers them.

A paper bag is too valuable to burn IMHO. We save them all, carefully folded, and reuse them until they are falling apart. A lot of tree went into each one and we're running out of trees. The paper mills don't go hunting down standing dead like we do. Every bit of paper re-used in a better planet. ;-)


As far as wasted BTUs, I suppose I should save my grass clippings and burn them, but it don't hardly seem worth it. If it ain't attached to the wood, it goes in the scrap heap. Microbes just love the stuff.

Most of my wood is winter cut, so the bark stays on pretty good, even after 2-3 years. I've got cherry that's down in the 12% MC range and the bark is still tighter than a tick to a dog. Bark don't have to fall off to make good firewood, that depends more on when in the year it was cut. Spring cut wood can lose it's bark before it's ready to burn, and winter cut wood may never lose it, particularly if it's covered or in a shed. I burned some 5-year old ash last year that was stored in the work shop and forgotten about, and the bark was as tight as the day I bucked and split it 5 winters ago.
 
If your making fire starters use dryer lint with the wax. Works great my wife/ and mother in law are candleoholics and I get lots of old used discarded candles. I use old egg cartons. The paper ones I just dump directly into, the plastic(foam), i line with tissue paper, news paper ect. put a good size wad into the compartment and then dump the wax melted wax in. let solidify and your golden. The wife wrapped some in pretty tissue paper and gave them to the inlaws for an X-Mas gift. We alway exchange atleast one homemade gift per year.
 
BLIMP said:
love the "Bark and sawdust have the same btu rating per pound as the wood it came from" statement but can u qualify it? this would make great fodder in the pellet forum where different pellets are deemed good or bad from opinions from experience

Not hard to qualify it as the btu rating in most wood species is very similar via poundage. per pound is the qualifier here. If the sawdust and bark were compressed to equal the density of the wood it came from it would essentially be the same. When loaded the sawdust and bark take up more space but will not burn as effciently as the logs do because of over oxidation and heat will escape up the stack or lack of oxidation where the fire is practically smothered. Many believe that pine is inferior to red oak however pine is actually a little higher on the btu chart "per pound" than red oak. If pine were compressed to the same density as red oak it might well be preferred. See if these links (and your calculator) can help sift through the shavings. http://www.chimneysweeponline.com/howood.htm http://firewoodresource.com/firewood-btu-ratings/
Struck me weird the first time I heard it too.
The problem with the pellets is possibly the compression rating and the effect heat has on the lignin* (spelling?) that holds the pellets together. {*the compound that naturally occurs in wood and helps pellets to bond when subjected to enough pressure/heat}. Enough heat on pine based pellets and the wood may decompress and lose the btu capacity, via over oxidation, that denser wood pellets have by their heavier nature. I'm not a scientist so most of this is conjecture. It would be interesting to know the stack temperatures of the pellet stoves while burning various density wood pellets. Those temps could tell whether there is a loss of btu's via combustion near or in the stack. That is...past where it would be of use to the consumer. Like the wood is just burning too fast to transfer the heat. In a well set up gassifier dry pine only really gives off that burning pine smell at start up because the burn is incomplete and combustibles are escaping the burn chamber in the form of smoke.
IMHO I think the data that the referrenced charts reflect are from controlled burn processes. Also I think there is a lot more infra-red heat transfer from a wood that oxidizes at a slower rate.
Never been a pert so I can't claim to be an expert. :bug:
 
Another good use for the sawdust...fuel for the smoker when working the bee hives. I am way too cheap to purchase those fancy compressed cotton fiber disks when I have so much free fuel.
 
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