A few questions from a prodigal son

Raw wood generator fueling gasification is what Ben Peterson’s book system was about.
A new sitting room couch for the wife had me forced to books/magazines stacks cleaning up and I surfaced a buried extra Ben’s book copy.
PM me a safe mailing address here on the DOW and I’ll mail it to you.
Ha! Just the book. No preachin’ from me. Promise.
Steve Unruh


Hi Tom, Running a generator on woodgas or chargas is relatively easy. The issue will not necessarily be how much wood you have access to, but rather, how much time do you have to prepare the wood for gasification? Wayne has a sawmill that produces material that is easily chunked up and a climate that can dry them out quickly. Charwood needs processed into certain sizes (based on your charcoal kiln) and dried to 20% moisture content. In PA, (and I’ll bet Michigan is similar), this can take several months to a year. What I’m getting at is you may find the time and energy you put into making all this electricity to grow plants in winter is not worth it. But then again, maybe it is. You will have to make that decision. If you want some real world experience in woodgasification, you definitely came to the right site.
As for nozzles for a charcoal gasifier, the Hexoloy tube Dave talks about is very durable. He has put many hours on it to know that it works well. I like the water cooled nozzle as it allows me to easily put some steam into the oxidation zone. The hot water could also be circulated for other uses. What ever you decide to do, we do not look on you as “wacko” as we are are already accused of that :slight_smile: Let us know how you proceed down this path of self sufficiency, it will be needed. Just yesterday a friend of mine was told by a local banker executive that the economy will probably hit a major stumbling block which he predicts will be the later part of this year. Things are getting interesting, and not in a good way.
Take care and until later,
Gary in PA


Wacko = Anyone who tries to run an engine on wood.


Steve U. Thanks for the offer. I have the Ben Peterson Bible. They are no longer available, at least on Amazon. I checked to see about getting his carburetor book. Out of print but some one will sell you one used for about $850 bucks. You need to hold on to the book you have. It will be very valuable soon.

Gary. I have watched all your videos. I am subscribed. Very enjoyable and information packed. They reason I never followed up on my current gasifier is exactly that it was just so labor intensive to produce fuel and I may be a prepper but as long as the grid is operating I’m a big fan. Without electricity, the future is bleak in my opinion. A lot of people think that if the SHTF will be just going back to how things were in the early twentieth century. I don’t think so. However the area I live in did not get power except in towns until after ww2 in most areas. My great uncle ran his farm with two Jacobs wind generators and he was the only one with lights and power for miles. This was in the thirties. It’s absolutely doubtful I’ll be able to accomplish my goals of self sufficient food production in a controlled environment using wood gas unless I get a lot of help. More help, more mouths to feed so diminishing returns on that but people that are heavily invested in PV are going to be shocked by whats coming that will make their systems non-functional and everyone I know that is using wind has as many problems as benefits from it. At least with producer gas you are in control if you can make fuel and maintain an engine, so I see it as the best power alternative to the grid.


Welcome to the group. :slight_smile:

Are you using charcoal filters for the aquaponic system? If so, it might make sense to start making charcoal. Activated charcoal is essentially charcoal exploded with steam… (you don’t want the water in engine charcoal, and it takes forever to dry it, but the retort and process itself might be dual purpose.)

What is your wood supply? That will make a difference. Consistency in fuel size important. If you don’t have a wood supply, and your friends also don’t have a wood supply @Matt Ryder works on pellet based gasifiers and is in Michigan. He also has an automated control system. And a heat exchanger system, that could be used to supplement the rocket stove heater.

If you have a wood supply but it can’t be made consistent, charcoal is probably the best way to go, because you post-process the charcoal to a consistent size without quite the investment in a chunker.

Keep in mind, because of the lower energy value of the wood/char gas, you are looking at less the 1/2 the output from the generator.

Honestly, because you need reliable service, and most power outages at least around here are only for a few hours. I would probably look at batteries. Then piggyback the woodgas on the back to recharge those or directly power the inverter they use. It also depends on how much electric you need to sustain your system. But some of the new LiFeP batteries can do like 5000+ charge cycles, and beyond just being a backup energy supply, you might be able to leverage it to actually save money in your whole system because I can’t imagine your electric bill is low…


There are two Cross Fire Gasifiers for sale here on the site. @toddharp You may want to get a hold of Todd Harpster

Ive built and developed direct wood gas systems for over 8 years. I have built some of the most advanced systems of their kind. If you go with direct wood gas, I would build a retort and cook your fuels down a bit. If you can do this reliably, you dont need to turn it too charcoal but cook out all the moisture. You are guaranteed to never have an issue and the machine will flow and run much more reliably with a less complex system.

The other option is to go charcoal. Processing is less labor intensive but you lose a bit of energy density from raw feed stock to usable fuel. If you use process heat for other things this will help reduce this loss and water injection or flash steam injection will replace some of those losses as well.

I did a tutorial here in the site to build an auto mixing electronic valve. This controller is now well proven. It is free

I am in Muskegon Mi. you are welcome to the shop anytime.


OK, you have been sand-bagging us a bit. I don’t blame you, lots of bad information and folks with bad intent on the web. You have done a lot of homework already, probably way more practical off-grid stuff than me. here is my take: yes, it is more than likely bad times are coming. God is good and He will give us as much time to repent as he can. He really doesn’t want to loose any souls to the eternal darkness. :innocent:
So, what is a man to do, to provide for his family, and his neighbor? Continue learning how to live life without the “System”. Study the old ways of food preservation, that still work. The Amish are a bit out-there, but they know about preparing for bad times. They prepare their own reserve supplies, and act as their own insurance company, pooling labor and food and resources and knowledge when bad things happen. Teach trusted others what you have learned. We don’t know if the world will end in fire, or in ice, or how long it will take, or if we will even still be here.
Don’t believe anything you see on USA network television. I see the lies everyday. Enough said, seek out truth, wisdom in many trust-worthy places.
Learn to live with less. Learn from “Great Depression” survivors. How convenient for the bad guys that most of that wisdom is gone now. Remember, don’t erase your / our history. We need it, warts and all, for learning.
edit Reduce your debt anyway you can. Pay off loans. Fix the old stuff that is made to last. Buy local. Support your neighborhood businesses. You can’t possibly store everything you will need, it will be a barter system economy.
West Michigan: :smiley: Beautiful, my favorite vacation spots are there. I grew up just North of Detroit, now I’m a Hoosier. Staying here. Blooming where I’m planted.
To whom it may concern… Mike R.


LOL. That’s just the epoxy coating that was inside the water heater. You can’t burn it with a propane torch. Not bad though. It has kept the steel from rusting. I have thought that maybe I should get some of that and coat high temp things with it. But probably very poisonous. Making a big (50gal) TLUD from the tank. Going to fire it probably tomorrow and see how it works. Chunking all that wood by hand was a bear. I’m beginning to see that a chunker is sort of central to any woodgas system.


Understatement of the year. :smile:

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I already make quite a bit of charcoal. Just the typical 55 gallon drum retort. Load it, fire it and then seal it. I grind it and charge it and use a lot of it in my garden beds which are fairly extensive. Wood? I have lost hundreds of Ash trees to the borer. I heat my house totally with wood. Average 10 full cord a year so a stack four foot wide, four foot high and eighty foot long. That not counting what I feed the Rocket Mass heater or the wood stove in the shop. When I built my WK gasifier I was cutting dead fall branches with a chop saw. Just too much work. Was going to make a chunker but other things got in the way. Now I believe it’s time for me to crap or get off the pot. Aside from the political madness I’m watching many geological signs that say the New Madrid quake is on our doorstep. Not the place to get into any discussions like that but for me time is of the essence as far as being able to acquire the materials I need to move forward. Already, and mainly because so much of it was made in China, it’s getting harder to get basic repair components for equipment. It’s important for me to have my own dependable source of electrical power but as important that I can find a way for the homesteaders that I have been involved with for many years, to be able to put together some sort of useable system with less fabrication skills than a hard core enthusiast has. That’s why I liked the idea of the Troy Martz open source unit. No welding required. Where we go one we go all. The future is going to depend on a persons self reliance and personal skillset but we are our brothers keeper and we will not survive or thrive on our own. Sorry to get preachy. Now I have a question. Has anyone dirverted the exhaust gas from what ever engine they are using into a chamber or some sort filled with processed fuel wood in order to accelerate the drying process?

I’ll have to check out those gasifiers you mention Matt. Are cross fires what they were building on Off/gridpro? If I ever get to Muskegon Il stop in. Thanks for the invite. Probably never happen though. I went to Traverse City yesterday for some supplies. That’s only 12 miles and it’s the first time I’ve left my property in about a month. Don’t get around much anymore.


Using engine exhaust heat has decades long been used for fuel drying. However, what I am proposing will require a lot more heat than the engine has to offer. It wont torify the fuel fast enough to keep up with the machine.

Yes the Crossfire is the product of Off Grid Pro

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Can you explain?

people that are heavily invested in PV are going to be shocked by whats coming that will make their systems non-functional



I track geological data. For various reasons the earths core is heating up and exerting a lot of pressure on plate boundaries. This is more the source of global warming than greenhouse gases. USGS is way under reporting quake activity. They have been constant, though small scale quakes on every plate intersection through the planet in recent years. There has been a series of minor quake swarms stretching from Iceland all the way Mexico. There have been volcanic eruptions and precursors to volcanic activity in Iceland and all around the ring of fire. Eventually these volcanoes will build enough pressure that there will be major eruptions. This will put enough ash and sulfur dioxide into the atmosphere to block the suns rays. During the eruption of two volcanoes in our historical recond, Mt Krakatoa and Mr Tubo. There was enough atmospheric pollution to create famine conditions worldwide. No sun, No PV. Not to mention that sulfur dioxide is what we refer to as acid rain. Acid rain deteriorates aluminum quickly. Most PV panels are framed in aluminum. I could be feeding you a bunch of conspiracy theory here but the conditions I’m describing are why I’m working toward food self sufficiency in a controlled environment. Whether it’s do-able is a big question.

Matt. I’m a long way from solving any fuel supply problems. You guys have been working these gas systems for a long time now and I’m sure you have explored all the options I’m just starting to consider. That’s why I join these sites. One thing I have learned so far is that running full tilt, my Rocket Mass Heater will hit over 500 degrees F. on the surface of the barrel with only a wad of sticks you can wrap two hands around. I pump that heat though a two foot wide by seventeen foot long bed of Cob. However I can see how that kind of heat could easily be circulated though a fuel storage container of some kind. I will be building something to try that out after the garden is put to bed for the year.


This is just my opinion, but I think you might be getting yourself a bit too worked up about the dangers of volcanism. Yes, big eruptions would be (and have been) disruptive, but I think you are imagining a scenario that is unlikely to ever happen. If there was so much ash and aerosols that solar panels ceased to function, and that the aluminum frames start to corrode, then there is about a snowballs chance in hell that all the trees are not going to die too (along with everything else, I might add).

If you want the challenge of building a really elaborate system of food production, I think that is as worthy a hobby as any. Lots of people fantasize about escaping to Mars when we have thoroughly wrecked this planet, but it seems to me it would be a lot easier to just build a sealed up tin can to live in here on earth. Is it possible? Sure, anything is possible. With enough dollars you can even land a man on the moon, and set up shop there (no volcanoes on the moon, afterall). Anyway, snide remarks aside, I am curious to see what you dream up.


That is fine. I was just trying to get a feel for where you were exactly. You are a lot further then most. I would try a charcoal gasifier to get your feet wet again. You already have what you need. You just need the larger chunks. The rest go in the compost. (technically, fuel grade should be run to a bit higher temp then biochar as it gets more of the tar out, but you may be doing that anyway and once the bed is heated up it will crack the tar anyway.)

Unless you have a mansion, that is significantly more then the typical house. You might look at insulation or filling up drafts and cracks. I know folks with a wood boiler that had a heated shop and 4 or 5 bedroom house that only used 5 full cords a year… The wood might not be dry enough, and is using too much heat boil off the water, which maybe what you were indicating in your comment.

You might want to check out this section (probably backwards) He is using a hoop house for wood drying. It is similar to a solar wood kiln. You might want to make some adjustments so you can get your tractor in or make it sectional so you can move it over your wood pile.


Hi Tom,
I am not an expert like many on this site are, but I thought I would try and answer a couple of your questions. You can indeed start a charcoal gasifier without a full hopper for a short run and it does work just fine. The extra carbon fuel cools the syngas as it creates additional CO - so that is probably why it is a good idea to fill it up. With less fuel you are just looking at less time before the unit is running low on fuel, the syngas starts heating up, and you need to shut it down to protect the engine. The Off-Grid Pro Crossfire is a good design, it will start generating syngas in 30 seconds or less and generates at least 5KW power - I ran out of items to load down the generator with for my testing. Right now I have all three Crossfire units that were built and I am looking to sell two of them. These units use the TIG cup nozzle they do a great job of dealing with the heat, and they are something like $5 a piece. Sounds like some fun projects, take care.


I didn’t take your post as snide Carl. Each of us has to look at what’s happening in the world and interpret the signs we see. I have no experience with wood gas. Building a gasifier was easy for me. I wake up in the middle of the night thinking about projects I can build. Been like that forever. The way I read the world says the supply lines are breaking and getting the materials I need may soon become impossible. The food supply is in disarray. When we were even allowed to buy seeds and gardening supplies this year they were gone in a week. I just cannot stand the thought that I cannot provide for myself. Never could. Whether I’m right about the volcanoes or not, the food supply is compromised and going hungry is a poor plan for any of us so I attack the problem with as much energy as I can muster in my old age.

Covid will kill us or it won’t. There is no political solution to the problem.

Thanks for the post Todd. I watched a lot of you-tube before I decided to get back into this. I thought that those cross fire gasifiers were well thought out, compact designs. I didn’t realize that there were so many variations of wood and charcoal gasifiers that all seem to be producing clean use able gas. I’m learning a lot here.

I am heating quite a bit of area Sean and our heating season is from October until May. Not many ways I can beef it up. I have an r-50 attic and R-19 glass batts in the walls with 2" styrofoam outside that and an inch of stucco over the foam. I’m sure there are places I could improve but I don’t want a sealed house anyway. I’d rather have a little extra air to breath. I guess I could mention that when I build this place I build several hundred sq feet of glass in the south face thinking I was going to get solar gain. After living here a while I learned that the sun doesn’t shine in the winter here. All that glass just bleeds heat. My wife won’t let me cover the windows. She likes the view.


Hi Tom,
Since you heat with wood anyway, extracting charcoal from that heating process becomes easy.
Use that charcoal as fuel for a gasifier might be an option for your idea thinking ?

Have wood = will have energy…


i personally sealed up mine quite a bit and found a few places that were just letting in cold air, it helped quite a bit. there are still some leaks, but the heating bill is a lot better. My big issue and my parents as well, was the window installers didn’t put insulation -around- the window frames. The cold air wasn’t coming through the windows, it was blowing around the windows. I put spray foam in around the windows. My mom decided to just get new windows.

You can get some solar heating via the windows in the winter. Probably not enough to heat the house. My uncles house had a full wall of windows, with a stone style heat sink and he claimed they only kicked the furnace on a few times a year. They were down by k-zoo. I remember we were there for easter, and there was snow on the ground, it was literally like 90 in there they opened up the doors. You are a bit further north though.


Hope I’m not hijacking Tom’s thread too much, But I started telling about my 50 gallon tlud so maybe I should finish the story. I fired it yesterday. I think it was a success. i got 29.49 pounds of good charcoal and 3.41 pounds of uncooked wood. The afterburner thingy I made out of coffee cans seemed to work very well, except during a few very strong wind gusts. The burn took about 3-1/2 hours. It made very little smoke, but one neighbor did come around because he smelled it. I agree with Koen. “Since you heat with wood anyway, extracting charcoal from that heating process becomes easy.” It was hard watching all the tar and volatiles burn off.

Here the leaves are not on fire, but you can see part of the flame because they create a dark background. You can see how far down the burn has progressed by the discoloration on the tank.

Here I have stopped the burn by taking the bricks out from under the tank, and putting a can in place of the afterburner. Wind gusts made flames come out of the bottom and scorch the grass.

I didn’t have a hoe, so I made something out of a can. Cans are very usefull. :smile: