one thing I'd like to play with is blacksmithing. I have a small forge
and a trashcan full of coal, so it's not like I NEED another way to
make iron turn red, but I regularly generate bunches of sawdust and I
just happen to have a spare blower just laying about. anybody here
ever built a sawdust fired blast furnace? seems to me the trick is
gonna be to get the mix of sawdust and air right and to keep it lit.
it might need a "pilot" of a propane flame and some sort of sifting
mechanism to act like a carbeurator to keep a steady amount of sawdust
entering the stream of air.
hey, it might work....
Of course, coal is ground to dust and sprayed in new boilers, but except as
some money sink, I can't see why you'd choose any method over anthracite. A
lot of things must be kept within narrow limits to keep the right mix.
You haven't checked prices and shipping rate for smith-grade coal, have
If you can show up at with a truck at the coal mine, even top-grade
forge coal is cheaper than the gas to haul it. If you live too far to
make that practical, then you don't even want to know the rate for a
pallet of bagged Old Smithy coal.
Nope, recognizing the difficulties, I merely remarked that it did not seem
worth the effort. A point which others have made over and over.
Oh yes, carbon density in hardwood makes it a much better choice for
charcoal, crotchety old caps-posters notwithstanding. Now, if he sets up a
turpentine distillation retort....
It'll work just fine if you can figure out a way to control the
transfer the sawdust to the burner.
I've tried to build sawdust burners for pottery kilns with limited
The main problem is feeding the sawdust into the burner. Fairly large
volumes of sawdust are required & if you care at all about efficiency
the rate of feed has to be constant.
I was pretty successful in making an auger feeder to mix the sawdust
with the airstream but had problems reliably transfering the sawdust
to the auger. I tried a funnel type supply to the auger, but was
constantly faced with the sawdust bridging over in the narrow neck of
the funnel thereby interrupting the feed rate.
Maintaining ignition is not a problem once the kiln is red.
A good strategy might be to build a fluidized bed for the sawdust then
draw off the fluidized mixture as needed. It'd be pretty easy to do if
the dust is coarse enough. The coarse dust from a two stage dust
collector might work in a fluidized bed.
If you are interested I can post some numbers about air/dust ratios,
dust densities, etc.
I'd really like to see a simple, workable sawdust burner design. It
might help a lot of smiths and potters.
On 23 Dec 2003 08:27:40 -0800, firstname.lastname@example.org (dave martin)
well, you already have a blower going, so I guess some of that air
could be used for the fluidized bed. if the blower outlet routes
through the sawdust bin on it's way to the burner and has baffles and
vents in it it just might work. could get exciting in a flashback
Basically what you have to do is very similar to what coal fired utilities
do with coal.
They grind the coal almost as fine as talcum powder, then blow it in the top
of the boiler, which may be 5-6 stories high, and allow it to burn in the
air while falling to the ground.
You face the same probelm with sawdust.
You need to aerate the sawdust so that it will burn.
Not an easy job to do in your typical shop.
S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
On Mon, 22 Dec 2003 22:57:36 -0700, email@example.com wrote:
That's different from a blast furnace. A blast furnace reduces iron
oxide ores to metallic iron, so you need a fuel that can give a
reducing atmosphere. You also need an atmosphere that's free of
impurities (particularly sulphur, the minor additions and any tendency
to excess carbon) Sawdust won't do this - far too many volatile
Even for smithing, I doubt if sawdust is usable. Perhaps if you could
burn it to charcoal first, but that's going to need a sealed retort as
you cant burn sawdust in a charcoal burner's mound or a drum.
Klein bottle for rent. Apply within.
Your'e right. I even thought about that difference as I was typing
that, but I went ahead.... late night, I guess. I 'spose what I was
looking for is more properly called a sawdust fired forge.... although
to be frank about it, a lot of what I'm curoius about is what it would
take to sustain a high volume sawdust flame.
No coal or sawdust needed. Use LP gas!
See http://www.reil1.net/design.shtml for a bunch of LP burner
designs that don't need blowers. Also a full-blown forge at
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