I asked a similar question some time back, before alot of the newer folks arrived here but there wasn't much response then.

I have a sawmill. It's a circle saw mill which translates into alot of sawdust. The sawblade has a 3/8" kerf so for every two passes thru the mill I generate the equivalent of a 3/4" board in sawdust. To me thats ALOT of waste.

One of the reasons I got the mill was so I could make my own firewood while adding value to the logs by recovering some lumber from them. That way I'd be able to buy a truck load of logs, make lumber to sell, and still get firewood from the slabs. If everything goes OK my firewood will cost me less than nothing. The firewood would come from the slabs, but considering how much sawdust I generate also I'd like to make use of it as well. I know I can compost it and I do but we're talking about ALOT of sawdust here.

The mill has hydraulics and a sawdust blower. I was thinking I'd blow some of the sawdust into a hopper which would gravity feed a hydraulic sawdust "press" that would create sawdust logs approx. 6" in diameter by 16"-24" long. They would be under alot of pressure and should be nearly as dense as particle board, which as you might know burns hot and long.

Now the question. What can I use as a binding agent to keep the home made logs from falling apart? I'm thinking if I'm cutting pine the sticky sap in the wood might be enuf to keep the log together but I'm less sure about oak, aspen etc. What do you think?

-- john (natlivent@pcpros.net), March 16, 2002

Answers

Hi John.. If you are only going to use slab wood to burn and mostly slab at that you will be tending your fire alot.We have a fireplace and it eats slabs like I eat chocolate!! As for the sticky sap from pine that means creosote build-up to me..I stay away from pine as much as possible unless it is well seasoned..You may be able to sell your green sawdust to pellet mills..That is what alot of the saw mill owners do here. I am also curious as to what you could use for a binding agent but I dont think sap is the answer???

-- Lynn(MO) (mscratch1@semo.net), March 16, 2002.

There has to be a binding agent, I have seen these sawdust logs for sale in stores, I have a friend who is a master chemist, I will email him and ask.

-- mitch hearn (moopups@citlink.net), March 16, 2002.

I live near a presto log company here that makes the type of sawdust log that you describe. These things are made with TREMENDOUS pressure and heat. Far more pressure than you are likely to generate with a homemade press. The electric power lines that go into that place makes me cringe at what their power bills must look like! They do not add any other binding agent other than pressure and heat.

Not to throw water on your idea, but you might should look at other useful ideas for your "waste product".

-- Tis I (really_tis_i@yahoo.com), March 16, 2002.

John, go to www.fao.org/docrep/T0275E/T0275E00.htm I think this will help you out a little. emory

-- Emory (NE PA) (et@hazleton.net), March 16, 2002.

The fire starter sticks you can buy in the store are made from saw dust and parifin They have a warning on them to not close the door while they are burning as they burn very hot .

-- Corky Wolf (corkywolf@hotmail.net), March 16, 2002.

These links may give you some useful info: The P 192 Log Machine, www.fpl.fs.fed.us/documnts/fplrn/fplrn208.pdf recently developed by Western Research (and Scientific Laboratories), Inc., 699 Second Street, San Francisco, Calif. 94107, is also said to convert 6 to 12 tons of any sawdust per day to 6-pound high-flaming logs by compressing it with an equal amount of wax (136). Some manufacturers add inorganic salts to their logs to give them gaily colored flames , http://www.make-stuff.com/formulas/flames.html

Another way to go, might be to make fire starters: Melt wax. Add scented oil as desired. Add sawdust until wax becomes a thick mixture, then pour into your molds. You can try substituting a starch binder or glue gun sticks for part of the wax to lower costs

-- BC (desertdweller44@yahoo.com), March 16, 2002.

Id try flour and water glue first,, cheap easy, and if it hold together long enough GREAT. Them ELMERS white glue would be next

-- Stan (sopal@net-port.com), March 16, 2002.

Hey BC,, that LOG MACHINE link doesnt work,, but I didnt think of using wax,, another use for beeswax ,,hmmmmm

-- Stan (sopal@net-port.com), March 16, 2002.

I like the corn starch/flour idea. I'm looking for cheap and readily available because there'll be fairly large quantities of sawdust to process. It might make the "logs" attractive to bugs but if they are kept dry it might not be much of a problem.

As far as the prestolite logs. There'll be no problem with generating the pressure. I have a hydraulic ram with a 12" bore. With 1500psi applied to it, it will generate almost 170,000 pounds of pressure. The heat is another matter. I suspect the heat is used to impregnate the sawdust logs with the paraffin.

There's a paper mill not far from here that extracts lignin. Thats the stuff that naturally binds wood together. I'm gonna look into that too.

As for burning slab wood. I have an outdoor boiler that'll burn just about anything. Being an induced draft there is very little creosote and the slab wood seems to burn quite well.

-- john (natlivent@pcpros.net), March 16, 2002.

Stan, guess the pdf sites don't work with the html link coding.

John, the combination of heat and large pressures on organic compounds can have explosive results, so proceed with caution.

-- BC (desertdweller44@yahoo.com), March 16, 2002.

Be VERY careful with those compressed sawdust logs that burn and make colored flames! Sometimes they blow up - no kidding. Had that happen a few years ago. The log exploded with such force that it knocked down the fireplace screen and bits of fiercely burning log flew out into my living room, on the carpet and on furniture. Was a very scary time. The fire dept told me that they had a lot of homes catch on fire because of these logs. Might want to carefully check out this idea.

-- Carol - in Virginia (carollm@rockbridge.net), March 16, 2002.

I make fire starter bricks with sawdust. Heat 4 cups water and 1/2 cup flour till thick. Remove from heat and pour over a gallon (est.) of sawdust. Mix well. Press on cookie sheet between newspapers (top & bottom). Lay a weight on top until it feels dry. Turn over (should pop out a one big chunk) Let dry completly and cut (I use scissors) into bricks. These work really well. Hope this helps. Jamie

-- jamie (jamie@nowhere.com), March 16, 2002.

Carol---I have no interest in making colored flames. As to the explosive force in pressurizing organic components---how does this happen? What would cause this in merely compacting sawdust?

-- john (natlivent@pcpros.net), March 16, 2002.

Steam. Another reason not to use stream rocks around your campfire ring. Same idea- the inside builds steam but its unable to escape then Boom. Hey, you arent in NC, John, are you? I have lots of uses for sawdust here! Try marketing it- 10 bucks a pickup load if they pick it up and load it themselves or something. Sawdust does compost fairly quickly- if you have land, think about using a fertilizer spreader to lightly cast it out and let it break down of its own accord- ive done this with cedar chips (used rabbit bedding) over the garden with good results.

-- Kevin in NC (Vantravlrs@aol.com), March 16, 2002.

I've seen the design for some of those pellet stoves, with an auger that turns the pellets so that they get enough oxygen to burn. Is it possible for you to build an auger into your furnace so that you can burn your sawdust without pressing it into logs, or are you needing the extra cash cow?

-- roberto pokachinni in B.C. (pokachinni@yahoo.com), March 16, 2002.

i am in a bit of a rush so i didnt read this thread very carefully. i hope my answer isnt too far off from the question.

i have seen "firestarters" where someone melts wax and mixes in saw dust and pours it into paper cupcake holders. after it cools it stores forever and burns slow but consistantly. i suppose you could make a million of these things or make large logs out of your own mold. gl :)

-- Najia (najia274@YAHOO.COM), March 17, 2002.

John, My husband suggests that you use sugar water to bind them. (Actually there is a technique used in foundry work in which sand molds and cores are coated with something known as "blackstrap foundry molasses" - a heavy molasses that has been chemically treated to prevent fermentation or souring.) It is not too far fetched that sugar water - which we all know is very sticky - would work well as a binder. The logs would need to be dried, of course, but that would not be difficult if they were stacked with air space between them. You have to do the same for regular logs anyway to properly season them. (You could even speed the process by building some sort of drying oven, I suppose.) The nice thing about sugar is that it burns away completely without nasty cresote forming residue like you would have with sap or wax. (Probably cheaper too considering that it would most likely be very diluted by water.)

Another idea that you might do something with... Lindsay Publications has a book called Experimental Science by George M. Hopkins that has a section on making carbon rods and plates by using a binding agent composed of molasses or syrup, coke (NOT the drink!), wheat flour and water. Seems like it could make logs as well as carbon rods - who knows? (Obviously the coke would not be needed for the logs.) Well, Good Luck!

-- Deborah Stephenson (wonkaandgypsy@hotmail.com), March 17, 2002.

Thanks all for the input. There's some good ideas I'll explore. I'm really not too worried about creosote. My boiler burns real clean. I've burned green pine and other green woods and the flues NEVER have creosote in them.

-- john (natlivent@pcpros.net), March 20, 2002.

Hard to tell if you just want to use for yourself, in which case it's your own liability - or if you want to sell some type of fire brick/fire starter, in which case you have to be careful with the exploding/ water content/ % of wax to sawdust content/ etc. One wrong brick could wipe you out - either way I guess. :)

Soybean protien (and other protiens such as leather shreds) is used to bind particle board, could go that route. Don't know how expensive.

How about selling the stuff for livestock bedding, any dairy farms around? Seems to use up all sawdust available where there is dairy or other livestock.

--->Paul

-- paul (ramblerplm@hotmail.com), March 20, 2002.