Small gasifier project

Hi all, I’m new to this forum while I should have joined long ago I gues.

I want to build a small woodgas generator, and I’ve already started building one a few years ago. But I’m king of procastination, so yea. I’ve mainly watched some Youtube vids where people made their own system, and I try to follow a design used by youtuber “MrTeslonian”, where he powers an old truck. I will just downscale it alo.

Parts I’ve got:
-Propane bottle as fuel reservoir.
-Larger pan as a lid.
-Springs from a washing machine, which used to hold the drum in place. (planning on turning those into an release valve system thingy for when the reactor tries to explode)
-2 different sized fire extinguishers, as a reactor tube.
-Pizza oven pan, which is just a perforated slab of metal. It will be my grate, holding the fuel in place.
-Thin walled bucket with lid, which will collect the ash/gas.
-“Snail house ventilator” from a central heating unit. (runs on 220 volts)
-Expansion vessle from a central heating unit, which I want to turn into a cyclone filter.
-Several random bits of metal tubes, with different diameters.
-Carburetor from an 5-ish hp engine. I want to turn this into an air intake regulator, allowing more/less flow of air into the gasifier.
-Car engine radiator, not sure if I can use this due to sut/tarr buildup.
-Heat exchanger from a central heating unit, not sure if I can use this.
-Radiator part from a central heating unit, not sure if I can use this.
-Old rectangular stainless steel frying pan, might be used as a filter medium box?
-Roll of steel wool as insulation?
-Metal perforated trashcan, which I could use around the main body, holding the insulation in place.
-Brand new 6,5 hp “honda clone” horizontal shaft petrol engine.

I might have forgotten some of the parts I have in my workplace. I can buy all kinds of metal from my local scrapyard which also sells new iron. But I like to keep this very low budget.

If I get the current engine running on woodgas made from this gasifier, my GF said I was allowed to buy me a CHEAP 6500 watt generator.

I am also interested in compressing the created woodgas. I’ve read that converting the vapour into liquid is really hard, so that’s not something I’d be doing. But I can get my hands on a refrigirator compressor (low output, high pressure) and an LPG tank from a car. (50-60 bars of pressure?)

I am not a skilled mechanic, but I can kinda weld. And the holes I burn into the metal, I can get closed again. Here is a list of tools I have:
-Angle grinder.
-Flux core mig welder.
-Hand drill.
-Regular saw.
-Off-brand dremel.

Considering the parts I have, this will be a “winging it” project. Where I just hope it all works when done. Any suggestions/comments are welcome.

Here are a few pictures I took over a year-ish ago.

*Those pointy sticks are 3 air intake tubes, which currently point straight upwards.


Welcome to the site Jahee

Not to discourage you from woodgas but have you checked out the small engine threads here. I’ve seen a bunch of generators run on charcoal an run very well. Check out Gary Gilmore’s Simplefire free plans are here on the site. You can build one in a weekend. Lots of info here just start reading and good luck with your build


Hello Jahee,
I would wait on building the teslonian thing for a while. For your time well spent
on a stationary 6-7 HP gasifier would be the imbert design.
Your work shows you definitely have the skills. You will be happy
with the results of the imbert design. AND, there’s no guess work,
no experimenting or doing over!
Use line A dimensions for HP up to 15 HP. It looks a little more complex,
it’s not really.

Check out my post in the Small engine section on this site titled,
“My first small engine run”. It’s a step by step how I did the build of an
imbert gasifier to the numbers. I think it will answer a whole bunch
of questions. I relate the parts to the numbers. Build a good reliable
gasifier from the chart, by the numbers. My advice never changes. Good luck.
Get back if you have questions.
The build can be done as you assemble materials as there are different
stages/parts to build. This will become apparent on my site. It’s my
history of a build.
Good luck,


Welcome Jahee.
I’m sort of in the same boat. I learned about wood gas almost 20 years ago. Started to build a gasifier, but other things crowded it out and I forgot about it for a while. My interest was renewed recently as I watched mountain after mountain of scrap wood at the two lumber mills right next to me go up in regular bon fires. Been re-reading some of the books I have, new ones I’ve found, and DOW threads.

My plan is to start with some simple proven designs, and work my way up. So ditto on the Simple Fire advise, and using charcoal for small motors.

Kinda weld? Your welds look better than some of the professional welders I’ve worked with. But if you can upgrade your welder with a gas cylinder, you’ll find that flux core with gas, or mig will make a better weld than that gasless flux core. And with the mig you probably won’t make as many holes that will need filled.

Love the enthusiastic “HAMMER!!!” Not a blacksmith by chance? Think I have at least a dozen or more. That’s after down sizing…

Why the long intake tubes?
There’s a thread about storing the gas. Typically not a great idea. You won’t be able to store much under pressure. If it’s going to be stationary and have frequent sudden power demands, you might consider a gasometer.

I’m not sure how well the pizza pan will hold up as a grate for the burner. For good gas you need red hot or hotter char, sheet metal just isn’t going to cut it for the hearth for very long. The stainless pan you mentioned will last longer, but heavy steel, cast iron or some kind of refractory are usually the way to go if you want it to last. But it is your first one, and after you run it a few times I’m sure you’ll want to tear it down and modify it based on what you learn, so I guess durability isn’t big deal at this stage.



Thank you all for the good vibes and info. Could not respond, had to wait till my account was approved.

@wobigtd , I do not plan on using the gasifier often. I also like cheap, free is even better. I can get a steady supply of free wooden pallets. I plan on using those as fuel. I might look into making charcoal from said wooden pallets, but I live in a city. So not sure as to what my options are.

@pepe2000 , I am really bad with names. But as far as I understand things, a “downdraft gasifier” and an “imbert design”, are the same. The gasifier I’m building, is one of those. I looked at your table, and it would take me a bit of time to fully understand it all. (partialy because I only know metric, and I see several non-metric values here) And in the end, I have to work with the junk I have. But I really appreciate your feedback, and I might take some measurements so you can check them out.

I have been limited to 1 picture per post, so here is the next one. Here it sits on the thin-walled bucket which is going to be the ash collector. I will be putting a tube in the side of the bucket, to extract the woodgas.

*PS: I’ve got some home improvement projects going on, so any further updates will be somewhere in the future.

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It seems I was limited to only 2 mentions per post as a new user, so here is the 3rd one:

@Grimm , as a 15 yo kid, I played around with a crappy budget stick welder. After several years, my dad bought himself an propper semi professional (used) mig welder, with one of those large bottles. I too used it alot and made my welds alot better.
As you might have guessed, I do not have alot of money. And a gas cylinder welder, a propper mig welder, just is out of my budget. For me, it’s cheaper and more easy to stick with flux-core for now. But I totaly agree that a propper mig welder is alot more fun to use.
If you would look at the gasifier “MrTeslonian” (on Youtube) made on the bed of his yellow-ish truck, you can see he too had long air intake pipes. They point upwards, and so do mine at this point. Just couldn’t find a picture of it. This should pre-heat the intake air, which is supposed to improve the efficiency? That’s why I went with long intake tubes.
In the pizza pan department: I totaly agree. But it’s what I found, and it’s what I will use for the moment. I will probably replace it at one point, but for now it should be functional.

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Hi Jahee,
Your intake tubes are exposed to outside temps for most
of their length and therefore offer no real “preheat” value.
They would preheat if they were flat against the hot housing
and then angled into the burner. Then wrap them with insulation
to preserve the heat. These just are at ambient (outside) temp.
Check out “My first small engine run” in the Small engine section
on this site. A completely illustrated how I did it gasifier build.
Should be helpful. For now I would do more research here before
putting too much stock in the Teslonian approach.


I will roll some of that rockwool around this thing. Not sure how long it will last, it might get burned off. Although the hottest part will be inside the bucket. Then I will use a perforated trash can around all of that, to clamp it together. Those air intakes point upwards/against the propane bottle. Might be able to take a picture in a few minutes of said air intake tubes.


Hello Jahee,
and welcome to the DOW.
You have given some good working conditions that will guide advice’s given to you.

You live in the city.
You will be using shipping pallets for you input woods stocks.
You want to work towards building a small electrical generating system.

OK. Living in the city makes it hard, hard to pre-convert those pallet woods into fuel grade charcoals. So you will be going with an actual wood input gasifer system.
The wood chunks, or chips you make from these pallets must be shaped and sized properly for your expected engine loading power.
Meaning using a downdraft constricted orifice gasifier you have to size-build and match the gasifier to that expected engine shaft power loading.
Read here for a DOW members guidance on that:

Dutch John will say from his experiences that the wood particle sized must be ~1/7th of the design selected constriction orifice opening.
So . . . small gasifier and you must make tiny wood chunks.
Pallet woods already have four flat sides; so to prevent fuel particles/chunks from flat sides stacking and internal gasifier gasses flows blocking you need to reduce down pallets chunks cut-made as irregular as possible. Quick rough chainsawing (quiet electric plug-in), then hand hatching will get this done. Saw around the nailed sections to keep nails out of the gasifier. They will clog up the system. Save these nail ridden chunks for anyone you know who fireplaces, or wood stoves.

As Pepe’s info shows; and Dutch John’s info will show; you will want to run away from a three air jet system and jump immediately to at least a 5 or 6 jet system.
Some have made three jet systems work. But these tend to be easy-making tars makers. It is the un-oxidized converted upper system gasses (tars) sneaking past in-between the hot faced air jets zone.

There will be much more experienced based advice you will be made aware of as you get to DOing.
Steve Unruh


Dutch John’s site will not link up auto here anymore?
And Google searching I only get his first Vovlo car vehicle system?

Anyhow. . .
Library (top tool bar) open up here on the DOW.
Scroll down to the “References” section.
Open up “Links” tab within that section.
Find and open up the link to: there.
From that page then go to the British flagged (for in English only) Micro Gasifiers.
Info and pictures of his three small engines sized “scrap-builds” there.
Read and learn.

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Thank you for your first reply Steve! (I see you’re making a new one)

Thank you very much for your reply. That info about wood particle size is really interesting. I went for a 3 nozzle design, because I feared that even more of them might get the fuel stuck. Adding 3 more nozzles right now will be hard, because I’ve already welded the lid of the bucket, to the propane bottle. I will just have to see how this will turn out.

I did already expect alot of tar and sut to be created, and I am planning to use multiple filters. Considering how often I’m going to use this gasifier (almost never I suppose), I am not too worried about cleaning it all out, and replacing filter medium where it requires a filter medium. (I also plan on adding a tar collecting bottle, so it might not be too bad of a situation IMO)

Someone else also mentioned that storage of the woodgas is very inefficient. However, it’s all a “for fun” project. And if I can get a 50-60 litres LPG tank filled @ 25-30 bars (in the future), it would be fun to cook on it using a regular kitchen stove. Waisting alot of energy in the process, isn’t of any concern to me.

@ your second reply: I’m going to stick with the .nl version, considering I’m also dutch. Thanks for the link!

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Forgot to add the picture I just took.

That top horizontal thing isn’t welded to it yet. The height isn’t final yet too. Want to add a springloaded system for the lid first.

I will be using 2 carb valves to regulate the air intake. If it doesn’t work, I could always remove it.

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Ah good. Your written english is quite good. I would have never guessed Nederlands. Non-American, yes from the SI references.
Maybe you can contact D.J. for a see-please visit, eh.

Collected up impurities is much more than about inefficiencies.
Using tree woods for power done well there are no more end “wastes” than could be used usefully on a small Urban plot.
A tar-maker and then collected/filtered out; and the contaminated filter stocks add up making for a off-site solid waste disposal problem that you have created. Only slightly better than the streams contaminating cooled and gas washing 3rd world systems.

Mr Telorsorsian pictures out in the underpopulated American desert southwest. Easy to bury hide; or just walk away and ignore, your sins out there.


I get the feeling that MrTeslonian has a bad reputation here on this website/forum. (had seen other people trying something “Teslonian style”, where others also tryed to convince them otherwise)

I have seen several of his videos on Youtube, and others. To ME, he explained the basic concepts well enough. And I considered it very entertaining too, because he played with random junk while “winging it”.

To be more clear on the design I want to follow: this is the video I want to base my gasifier on.

I’ve seen others too, and I will implement some other ideas and/or suggestions. But being very exact is a hard thing to do, when you are playing around with junk and stuffs you already have. (vs buying components)

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Ha! Ha! Exactly how D.J. expressed his three engines small made-from-junk systems compromises on his Micro Gasifiers.
Versus; his purpose engineered two vehicle systems.
You are birds of a feather.
Steve Unruh

For me Mr Teslonian would have validity IF he was fueling sustainable only with the desert brush around himself.
Woodgasifiers eat woods at the rate of 20-30 pounds of wood for every 1 gallon US (4.2 liters) of gasoline an engine would use. Why we here jokingly call them wood-hogs. I like my bacon. Like pork chops. Love pork roast.
Much of the American SW was de-treed already by 1800’s on location silver, copper, and lead smelting. And also the early steam railroads.
Last thing the dry, dry; slow, slow growing American SW needs is folks zoom-zoom raping it some more just to get their vehicle rocks off.
No-sun winter homestead wood-power supplementing, O.K. That is Living Off the Land, lightly. Not brute-forcing short term ripping off, ON/of the land.


Hello Jahee and a big welcome to the DOW.

Before pressurizing any wood gas please give it a lot of thought . While pumping the gas into the tanks if for some reason you get air mixed with the gas you could create a bomb. If the mix was anywhere close to a 1 to 1 ratio and you lite it off at the stove the flame could run back through the gas line and into the tank . Boom !!


Thank you for your reply Wayne!

I will indeed give it plenty of thought before I presurize the created woodgas. Bombs do have a purpose, but I don’t want any of them near me. (or going off near me)

But (long term) storage of said gas will be a future project, when I’ve got the gasifier up and running. It’s just a secondary goal, which doesn’t impact my current project at all.


In all the discussions that I have seen, I don’t remember anybody pressurizing woodgas at a higher pressure than about 8 bar (approx 120 PSI). I wonder if any mixture of it might have an auto-ignition point if getting close to 25 or 30 bar? Not saying that it does, just curious.

Pete Stanaitis


To ignite it, it would have to have free oxygen. No?