On the subject of charcoal - I saw a web site that showed how to build a
really cool charcoal making furnace. Basically 50 gallon drum in a brick
enclosure. There is an exhaust port on the top side (barrel mounted
sideways) that is piped around under the barrel with holes along the pipe
under the barrel. You fill the barrel with all the wood you can stuff in
there. The theory is you start a wood fire under the barrel and once the
inside gets hot enough the wood starts emitting flammable gas which pumps
out the exhaust pipe to the underside and burns like a gas stove burner to
keep heating the wood after the starter fire burns down. So its self
sustaining and self regulating at some point. Once all the wood is good
charcoal the flammable gasses stop coming out and the heat source goes out
on its own. Looked really cool.
One caution.... you're building essentially a ramjet engine. Too little gas
flow can lead to too much internal pressure and WHOOOOOMP!. If there are
specific assembly instructions, follow them to the letter, then stand waaaaay
back the first time you fire it up.
Far out! Exploding stuff. Doesn't it need a decent source of oxygen to do
that? The design pretty much creates a sealed environment that precludes
oxygen... At least after the first little while.
I was thinking more along the lines of a boiler 'explosion', where the internal
pressure ruptures a seam or other tensile failure. That's why I didn't write
BANG. 55 gallon drums are pretty thin walled for a pressure vessel. Think about
what's happening. the initial fire generates combustible gasses, which expand
due to the applied heat, and the increased pressure forces them through the
'burner jets' underneath. These gasses are ignited, adding to the applied heat,
increasing the pressure, which makes the flow rate through the 'jet' increase,
which increases the btu output, which increases the applied heat, which
increases the internal pressure, which is sooner or later constricted by the
flow restriction of the jet as the flow rate through the orfice approaches mach
1... Whooomph! See Bernoulli's principle and sonic choking for the full math
Charly (just trying to keep y'all safe out there)
I follow you. I'm assuming the outflow pipe would have to be some minimum
diameter and the burner "jets" having a combined minimum diameter as well so
that "r" out is never greater than the internal pressure.
GA (still in one piece inspite of the dangers - for now)
Try natural gas and forced air. Hot enough to puddle on a cold dry winter
day, welding heat year round, even in 100+ August. It's all about air
density, and how much fuel you can shove in. Too oxidizing? Add more fuel.
A 1/2" line and an 8" blower on a 1.5 horse motor into four burners in a
24X4X4 box. Can you say 3000 degrees? I can. Best $150 I ever spent.
Granted, there are some limitations, but for heavy welding of billet it
can't be beat. Add a 25#LG and you've got a factory for damascus. There's
fair money to be made just making billet and selling it to other makers as
stock. I don't have any trouble getting $50 a foot for knife size stock
from cable. That works out to about $80 an hour of 'getting sunburned'
Sounds cool as anything! :)
And not all that tedious finishing work and second guessing the
fickle market and traveling to shows, either I suppose. :)
Where do you advertize, Charly?
As far as being sunburnt, I -stayed- sunburnt from early April to
late October -every year- and didn't make even $40 an hour. :)
What do you think GA? :)
Alvin in AZ
Well since I already have a job and my hobby ambitions include forge welding
I figure I'll know what I'm doing in say... ten more years or so ;-) I'm
thinking if I ever get to the point where I know my stuff and I get
thoroughly sick of playing the high tech game, I'll start trying to make an
income from blade smithing and related things. Preferably after the 401K
plan has had a chance to grow a bit.
I don't advertize, word of mouth keeps me as busy as I care to be. I've
got a permanent sunburn on my neck, it never goes away, so I guess
that's my proof that I'm a real Redneck. I tried advertizing ONCE, made
back about half of my investment. Waste of money. My rig takes about 20
minutes to get to heat, and I can cook two pieces of cable at a time.
The hammer has custom dies, so I get a thickness and width dimensioned
billet out. It'll turn two feet of cable into two feet of billet in
about ten minutes. Two feet of billet makes a really nice short sword,
or a pair of knives.
I get $50 a foot for cable to billet, no folds. (Folds are extra, how much
depends on how many folds.) This leaves a billet that you can still see the
wires in, looking rather like a piece of rope that's been run over by a
truck. The wire is oilrig draw wire, so it's probably 1095, 7X19 extra
flexible @ 1.5 " dia. . It will harden up past 'file hard' in water, and to
'file hard' in oil. I have a blade that has held a hair popping sharp edge for
eight years, so it 's got some carbon in it. I know it's damn tough, think
about how much five miles of thickwall drill string weighs. It ends up right
at .300" thick by not quite 1.75" wide, which seems to be a good starting
point for knives. It forges nicely at low orange, and doesn't exibit any
narsty 'memory', like the 6160 axle stock did. Leave me an email, we can work
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