Thanks again for doing everything you do. It is with great pleasure I write to you again to contribute some of my knowledge. I mean no offense to Caspar d’Gonzo, but after reading his article I have the notion that he has not yet actually constructed a gasifier based on the FEMA instructions. Though his article was very good about covering the theory and basics.
I was first fascinated with gasification when I saw them make a gasifier on The Colony. I read about it and planned to build one. Not long after I almost wrecked my Jeep while driving through northern Pennsylvania when I saw someone using a home-made gasifier on a car. I pulled over and chatted with them and now I really had a passion instilled in me for an alternative energy vehicle.
Fall of 2010 I had a college course called Alternative Energy, and the final project was constructing something relevant to the class. Some classmates and myself tackled the FEMA wood gasifier. Other groups built solar food dehydrators, small hydro-electric generators, waste oil burners, etc. The FEMA gasifier instructions are a good starting point, but far from all you need. Ingenuity and creativity will get you from the FEMA instructions to a working model.
I sized my gasifier to run the 134 cubic inch, 72 horespower engine in my 1963 Jeep CJ5. At the beginning of my project, I wanted to run that CJ5 with the gasifier. Now, I see that this will wear out an engine faster than normal fuels, so I will be building a dedicated gasifier powered vehicle in the future. Also, the gasifier ended up being very large overall, and requires a pickup truck or trailer. It would not fit in the back of my CJ5.
I was fortunate enough to have full access to a local salvage yard that was sympathetic to college students. I could go out and pick through acres of scrap, and I still could not find some of the items that FEMA called for. The instructions are outdated. Be prepared to deviate and get creative.
Some things I learned…
Harbor freight has the cheapest ball valves for the carburetor unit.
Garages have 125 lb grease drums/gear oil drums that make good filter housings. They usually throw them away or use them for garbage cans. I got one with a re-usable lid just for asking.
Home Depot sells a fireplace sealer in white tubs that worked well on the inside to protect the metal from heat cycle fatigue and seal welds and gaps. But be sure to put it on thin or it will never cure.
I used two 55 gallon drums from the scrap yard instead of garbage cans. They’re thicker and usually found for free, but make sure they didn’t have anything in them that could poise a health risk when you have a fire inside.
For the shaker bowl in the bottom of the gasifier, I found a stainless steel colander (bowl with lots of holes) large enough at a restaurant equipment supply store. They had lot’s of sizes and very economically priced.
I used flexible steel exhaust hoses to connect the gasifier to the filter and the filter to the carburetor unit. They were kind of pricey at my local auto parts store but I was having trouble locating heat resistance flexible pipe.
I used a 4″ Attwood Turbo 12v inline blower to draw a vacuum at the carburetor unit and get the gasifier going. This fan worked really well and I found PVC pipe fittings at Lowe’s to connect it to the exhaust pipe. These fans are built for pulling fumes out of boat hulls, so they’re typically advertised as spark-less, and the best price I found was online at walmart of all places. This fan was really useful, because by flipping the wires I could run the fan backwards and blow air into the gasifier to fan the flames on start-up. Switch the wires back and pull the gas through.
The only free fuel I could get my hands on at college were green pine wood chips made for mulch use. I would not recommend that less than ideal fuel, but it did still produce flammable gas. I had tar and filthy water pouring out of my filter. The FEMA design for a filter was really ineffective. When I get back into the gasifier project I will be researching what other people are using because a can full of wood chips will not keep your engine running for long. Lot’s of tar and moisture were bypassing it. Obviously, I did not have enough temperature drop for condensation and particulate filtration going on. The fuel definitely needs to be a good wood, not pine, that is dried. Dried goat manure was used with success on the PA Apocalypse TV show.
The only testing I did was on a 6 HP Briggs & Stratton small engine and it ran fine on the gas I was producing, but when I took the head off after test running there was a lot of tar inside. I was always able to light the gas coming out of the gasifier outlet for entertainment value and have a nice pink or orange flame to verify it was producing gas. Also, I only used my gasifier while stationary, not mobile on a vehicle, so I was frequently shaking the bowl in the bottom to pass ashes through it and pushing the fuel in the top into the fire tube. Mobility is a must with this design so that shakes and bumps going down the road keep things running, but other designs exist that are intended to be stationary.
Right now I’m playing with burning waste motor oil and vegetable oil in a 1967 military surplus M35A2 (“Deuce and a half”) I purchased with great success. For now, my gasifier will sit and wait until I have more time to experiment with filtration and quality fuel. I hope to find an older 4-cylinder truck, like a cheap Chevy S10 to mount the gasifier on.
Good Luck with Gasification, – Josh in Pennsylvania
The recent article by Caspar d’Gonzo in SurvivalBlog left out the advances by the open source group gekgasifier.com
They have taken the WWII design into the modern era, with a much more efficient design, as well as a design that is easier to start and produces much less tar than the FEMA design. Best Regards, – Bill M.