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I Forge Iron

Has anyone tried a "Wood Gas" forge?


cilbuper

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Greetings,

As I am new to iron working please excuse this post if this topic has already been covered.

I recently was introduced to the production of "wood gas" which is a syn gas or producer gas. It is essentially CO (carbon monoxide). When you see wood burning you are actually seeing the CO that is coming out of the wood igniting, giving you the flame. It is a very simple gas to produce and can be made from any biomass from wood, wood chips, saw dust, paper, cardboard, leaves, grass clippings, etc. The heat output from the gas varies with the amount of oxygen available and can be increased with a blower, much like adding oxygen to coke, charcoal, coal or wood. The temperatures will reach 1500 degree farenheit without problem and have heard of some setups reaching 2000 to 3000 degrees.

Making wood gas is not too much more difficult than making charcoal in a 55 gal drum. In fact, making a wood gas forge should be a "marraige" between a simple brake rotor/drum forge (with a blower/hair dryer setup) and the charcoal drum. I believe that when you make charcoal, most of the gas that is given off is CO and is lost in the process.

My theory is that we could eliminate the step needed to make charcoal and utilize the lost energy from the fuel needed to make the charcoal and the mass lost from the charcoal (which is converted to gas in the process) itself. My initial calculations seem to indicate that there is a 200-300% increase in the amount of energy recovered from the wood if converted and used directly as "wood gas".

If this could be done there would be almost no need to buy fuel as free wood/biomass can be found almost anywhere: pallets, builders/contractors, tree trimmers, lumber mills (scrap), lumber yards, landscapers, you name it!

A little more info on Wood Gas. Wood Gas also used to be called "town gas" as it was the main gas that was used/piped throughout town before petroleum was discovered. This was the gas which burned in street lamps at night to light our town streets! It is a truly amazing "re-discovery" which I happened to stumble upon while doing research on WWII.
During WWII the Germans (and I'm assuming Amerricans/Brits/etc) needed to improvise when it came to fuel for their cars/trucks. Well I stumbled upon the report that over 1 million German cars and trucks were converted to wood gas burning vehicles! It is truly amazing that this gas can be used to power ANY internal combustion engine! It works the best with a gasoline powered engine but I believe that even a diesel engine can be properly modified to run on CO (Carbon Monoxide). I am not sure if newer fuel injection engines will work but older engines with carburetors sure will. I have seen video of tractors running with wood gas as a fuel!

Sorry my first post is so long but I am just amazed at what I how little I knew about what wood can fuel (I could write a book about that which I did not know!). If anyone has any questions I would be happy to answer them. If someone would like to see some more information I will make a post with more indepth info and videos of this gas.

Cilbuper

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Basically, my humble understanding is that if it burns and creates enough heat to bring iron to forging temperature then you can use it for blacksmithing.

If given the choice of tossing wood into the forge and using it, or having a setup to convert wood energy to wood-gas, I would likely choose using wood in my forge. My concerns about converting wood to wood-gas include:
- needing extra equipment and thus money, space, etc. to convert the energy
- using time for the conversion
- the challenges of finding the right nozzle size and gas forge conversions
- storing, compressing and delivering the gas
- and last but most important *safety* in the manufacture, storage and likely process of pressurizing a gas prior to use.

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Basically, my humble understanding is that if it burns and creates enough heat to bring iron to forging temperature then you can use it for blacksmithing.

If given the choice of tossing wood into the forge and using it, or having a setup to convert wood energy to wood-gas, I would likely choose using wood in my forge. My concerns about converting wood to wood-gas include:
- needing extra equipment and thus money, space, etc. to convert the energy
- using time for the conversion
- the challenges of finding the right nozzle size and gas forge conversions
- storing, compressing and delivering the gas
- and last but most important *safety* in the manufacture, storage and likely process of pressurizing a gas prior to use.



Most of these issues are a non factor. You make the gas on demand by starting a fire in the fuel container, allow it to heat up, add your dried (the drier the better, more energy) biomass, cover the container, turn on the blower, wait till the white smoke is cleared out (5-15 seconds), light the flame and you are in business!

The process is very simple. You could make a wood gas forge in 2 hours, maybe less with a 55 gal drum and a smaller one to fit inside the 55. Some piping and a blower and that is about it.

I have heard of people making a large burner for less that $30 total. Most pieces can be found in abundance at a scrapyard (old water heater, drums, etc) and either free or very cheap on Craigslist.org.

I'm set on making one of these. I'm going to make a simple charcoal brake drum/rotor forge first and it will be convertible into a wood gas forge as well. I'll make a how to for everyone! I'm REALLY excited about this.

Thanks for your response!

Oh, one more question. I know that using coal, coke and charcoal with iron turns it into steel with the addition of carbon. Will using only a gas hurt the metal working process?

Thanks again!
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[quote=cilbuper;127070

Oh, one more question. I know that using coal, coke and charcoal with iron turns it into steel with the addition of carbon. Will using only a gas hurt the metal working process?

Thanks again!

Edited by arftist
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This has been discussed pretty extensively here a while ago, Whitebear (I think?) was using his wood gassifier to forge with and there were people casting with them.

There're a lot more things released than CO during pyrolization and most of them are flammable. The highest temps come when all the other stuff has burned off and all that's left is CO or if you get it right mostly straight carbon gas.

Frosty

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This has been discussed pretty extensively here a while ago, Whitebear (I think?) was using his wood gassifier to forge with and there were people casting with them.

There're a lot more things released than CO during pyrolization and most of them are flammable. The highest temps come when all the other stuff has burned off and all that's left is CO or if you get it right mostly straight carbon gas.

Frosty


you are right about it producing more than just CO. The source I was reading didn't make it very clear as to when it was just CO being produced. I believe prior to the wood becoming charcoal there is methane and another flammable gas.

Thanks for the correction!
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I couldn't find the edit feature for my first post but I wanted to correct my posting about what gases came out of wood. While it does produce about 20% CO, it also produces 20% Hydrogen, about 2-5% methane and some N2 (nitrogen).

Does anyone know if nitrogen is harmful to forging?

Thanks!

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No the "air" we use in all our heating means---save induction or solar---is mainly nitrogen.

I must admit being a tad skeptical when folks say "You could make a wood gas forge in 2 hours, maybe less with a 55 gal drum and a smaller one to fit inside the 55""; after having admitted that they have not made one and do not know of anyone who has made one. Gas forges are not brakedrum forges; they are enclosed insulated items and usually the *insulation* is the most expensive part of them. Burners are often simply made from plumbing parts. Actually it sounds like you meant to say "you could make the gas producer in 2 hours...." As it doesn't address making a forge. I've been to several Gas Forge building workshops and even pooling equipment and skills we averaged longer than 2 person hours per forge.

BTW 1500 degF is pretty cold as far as a forge goes---we were using one over 2000 degF Sunday---had pieces weld together in the propane forge just touching! (a piece of 2.5" square stock and a 3/4" rod stock,had to hammer them repeatedly to get them to separate and of course NO FLUX!)

Note that most of the charcoal making plans I am familiar with *use* the flammable gasses produced to heat the retort for charring so it's not discarded; research would be better than belief.

The gas used in cities for lighting was generally produced by running steam over hot coke.

Wood gas is a neat technology, especially for remote areas but it is not the answer for every problem.

But enough of the nay saying---Please work on making a wood gas forge and let us know how well it works for you! Keep track of your time and materials too.

You may want to compare it with a waste vegetable oil forge to see how they stack up against each other.

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Hi everyone, my first post here, couldn't resist. It will work, I'm not sure how hot one will get, but I have been metalcasting for a few years now and I started experimenting with gassifiers for a foundry burner. Someone found a link to a small gassifier and I was off and running. Here's the link: Biomass Energy Foundation: History . I built one and I can tell you they do work. I was able to melt copper fairly easily with mine at one point, and I believe with a proper setup they can reach much higher temps.
Word of warning, though. Do not use it indoors. They produce copious amounts of smoke on startup and CO gas while they are running, a good way to wind up dead if you aren't careful.
The "Dassifier" does have its limits, and can be finicky to start and operate. I like the idea due to the fact that there is minimal processing of your fuel source, and not much waste produced either. I ran mine mostly on wood pellets, and it would use about a third of a bag on a three hour run.
I am currently in the planning stages, nothing on paper yet, of the MKII version, my little dassifier bit the dust as it crumbled internally after setting out all winter. Hopefully I will have something to show in the next couple of months, after I get about a hundred other projects cleared off the bench first. Hope this helps, and good luck.

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Pretty much *ALL* forges producing heat by combustion will produce CO; the "clean burning" ones tend to be more dangerous that the dirty ones as you *know* that breathing that nasty greenish coal smoke must be bad for you; but the invisible propane exhaust may be worse!

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Hi OddDuck. Nice to see you around here. I was about to point this feller over toward BYMC, but I guess you came to him. :)

My main complaints about the Dasifier -- aside from the finickiness you mentioned, which I haven't experienced first-hand -- are that (1) it seems like it'd put a lot of unnecessary miles on the air compressor, considering that (2) there are simpler ways to get steel hot. Any thoughts about either of those issues?

Matt(22191)

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Matt, yeah there are definately simpler ways, but once this is set up and the learning curve on it is met, it's no more complicated than a solid fuel forge I would think. This would replace the reil-type burner in a gas forge, so the actual forge itself would be pretty simple. Here's a pic of mine (if it works this way, not sure about posting pics yet)
dasifier1.jpg
As you will notice, my air supply for the ejector portion is just an old compressor out of an air conditioner. This was just a POC (proof-of-concept, or piece-of-crap, jury's still out...:rolleyes:) so it's a bit on the crude side, and not made with the best of materials.
Once set up and in use it would be nearly as convenient as a gas forge, and easier and cleaner than an oil fired forge, with less fuel processing than a solid fuel forge. I think it may have a niche, worth experimenting with.

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"no more complicated than a solid fuel forge I would think"

Like "Take a shovelful of dirt out of your yard, stick a piece of black pipe in it to the bottom, place a blow dryer in the other end of the pipe"

Must be real simple! Or perhaps you should research over "think"

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Bah. Winter's not so bad. We use it to weed out those who don't belong here...:P Suppose that could be said of a lot of places in the country, the Dakotas, the Upper Penninsula, upstate NY, etc.
Thomas, don't get me wrong, I know it's not that simple, nearly anything will work to get the job done but having the correct tool and method for the task at hand is always better. I am a mere newbie at smithing and I shall not presume to know more than those who have been doing this for a long time. My son and I are going to start out with a solid-fuel forge as a matter of fact due to the simplicity and versatility of that method (plus the fact that I have most of the junk to build it laying around the yard...) I was trying to make a relative comparison as to ease of use. From all my research the most important thing in using a solid-fuel forge is fire and fuel management, what the fire is held in is not as important. And please correct me if I am way wrong, I have much more book-learnin' on this subject than actual experience.
Cilbuper, I think it's a viable method. You would have to build a gas-fired style of forge to use it, but once it's up and running it should work quite well. Plus you can tell all your friends that your forgings are made by using biomass and recycling, so there's some extra brownie points for ya. ;)

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This sounds like an exercise to see if it would work more than a practical application. Isn't it easier to collect your wood, convert it to charcoal and using the gas produced to generate the heat for the charcoal production (proven technique), then use the charcoal in a solid fuel forge?

Would be an interesting experiment though but perhaps not that practical.

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OddDuck; I'm really happy that you are introducing this idea into the forums; my suggestion is to just stay away from posting info that you are not up on and so avoid any issues with areas you don't have the background in. You have a lot of great information to share with us and then you go getting into areas where you don't have a firm basis and it makes your other info suspect.

"Hole in the ground forges" are probably more common world wide than other types and great work has come out of them. Skill is more important than the tools! I've done a pattern welding demo using a chunk of rail and a clawhammer with charcoal sieved from old bonfire remains and an improvised firepot.

Fire management is not very hard at all if you use charcoal. It is more difficult for coal and coke (with coke most of the issues being starting it and keeping it from going out).

Of course using charcoal you are also using "biomass and recycling"

Now living in the country I would be much more interested in a power source to run a triphammer than a replacement for a simple easy to use forge.

If you are interested in the general use of biomass to produce heat "The Mastery and Uses of Fire in Antiquity" by Rehder might be an interesting read for you.

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Now living in the country I would be much more interested in a power source to run a triphammer than a replacement for a simple easy to use forge.

If you are interested in the general use of biomass to produce heat "The Mastery and Uses of Fire in Antiquity" by Rehder might be an interesting read for you.


If the triphammer or powerhammer is driven by an internal combustion engine, you can use woodgas for that as well. It is all a matter of what is available and whether you have to pay for the biomass.
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