Sizing a Simple Fire Reactor (Beginner)

Hi all,

I’m new to gasification, and I was hoping to ask for your advice. I’m planning to start out by building a no weld, Gary Gilmore Simple Fire charcoal gasifier, to power a 212 cc Predator OHV Honda clone. Mine has a 1" ID air intake.

I’ve read a number of threads and watched a number of videos, and I was hoping to ask a few questions before I start bending metal. I saw this thread on the forum started by Alex Taylor, discussing making a simple fire from a 4 gallon, stainless steel pot:

That seemed like a nice approach to a first charcoal gasifier, but I thought that a bigger container supporting more than a ~1/2 hour runtime would be good, just to practice running an engine stably for longer times. After some poking around, I found these 14 gallon, stainless steel fermenters:

They’re 19" tall, 16" inner diameter, and have a clamping lid with a silicone gasket that must be specced to take at least some heat. I’m really interested to try this, if I can find one used for a decent price.

To get to my actual question, I see that the 14 gal. fermenter is made of 20 gauge stainless, per the manufacturer. I see a lot of people making their reactors from propane tanks and water heaters, and I’m sure thicker metal is always better, but I also see people with stock pots, like above, and steel barrels that must be pretty thin gauge. I haven’t seen any explicit guidelines in any of the threads I’ve read; would anyone care to comment? Would a 20 gauge stainless steel vessel like this fermenter be:

A: Suitable for long duration operation of a charcoal gasifier powering a small engine
B: Good enough for a beginner’s learning/prototype gasifier that won’t have a long service life
C: Unsuitable for any use as a gasifier reactor
D: Something else?

Also, with a 1" air intake on that 212 cc Predator, can I confirm that I’d want a 1" air intake and 1" wood gas outlet on the reactor, like in the original Simple Fire plan in the library? Also 1 1/4" hoses?

Lastly, it seems that a lot of people like the Kristijan Leitinger flute nozzle, but that it may take more operator savvy to keep the nozzles from plugging with slag. As an absolute beginner, does anyone have an opinion as to whether I should stick with the original Simple Fire open horizontal, consumable nozzle, or could it actually make my life easier to start out with a flute?

Thank you for your patience with this long post, and I’d be grateful for any suggestions.


Welcome to the forum!

You could always get a Hexoloy silicon carbide nozzle from eBay, it will fit into the 1" coupler if you grind the threads out on one end.

They’re probably the only way I’d run a single jet for a charcoal gasifier. @d100f has ran the same nozzle for hours and hours with no real wear.

With that method you could maintain the No Weld style.

20ga stainless is thin and finicky to weld with, and may be prone to stress cracks if the gasifier is subject to a lot of vibration.


Also for the gas routing hose, the smallest I would go is 1".


Hi Carbo Welcome along , Do not worry on the thickness of the container if you are planning on constructing it with screw fittings rather than welding , charcoal is a fantastic insulator and so will protect the container pretty good , if you get some 1 inch galv fittings you can open the container up with a step drill just enough to allow the fittings to push through and then seal with a little high temp silicon and a large washer and nut on the inside will work great top and bottom , also if possible on your outlet try and get as much steel pipe coming from the gas outlet to allow the gas too cool off so as not to melt your gas pipe to fast .
A container that size should manage a small engine for maybe 3/4 hour before you will need to start shaking the drum to let the charcoal drop down as you will only get about 9 inches of burn time with that height .
Good luck , let us know how your getting on and we love photo’s so get snapping .


Welcome to the site Zeve. Those 14 gallon vessels look kind of perfect for a first simple fire build. Making sure the lid seals and you can eliminate any leaks in other penetrations is crucial. I am looking at that bottom port with the ball valve. It is too low for using a flute or hexaloy nozzle IMO. It would soon plug with ash however it would work with something like this Brian White design. A pipe with a 90 degree elbow laying on the bottom of the vessel and a riser with the drilled pipe cap would work. Still no welding involved. With a relatively small container like that getting rid of the updraft heat will be an issue as Dave commented. With a taller container, like the propane tank builds, the mass of the fuel absorbs a lot of the heat and it becomes less of an issue.


Thanks for the videos Mr. T

On the video if you ask the gentleman why the motor quit when the hose was disconnected I’m sure `he would say it ran out of wood gas . In reality just the opposite , too much gas , the mixture temporarily went too rich :slightly_smiling_face: