Wood Gasifier … I am Starting to Build It

On a couple of occasions I’ve talked about wood gasification as both a heat source and for electrical power generation (here and here).

On our recent road trip across North America I finally took action and purchased a GEK III (a kit of steel parts and accessories) as the basis for our wood gasifier.  I bought the kit from All Power Labs in Berkley, California on our way back home, and we hauled two steel barrels of parts (a 30 gallon drum strapped to the back of the van and a 16 gallon drum buried in the back) for the rest of the trip.

We were concerned about crossing the border with the kit; we declared it as a wood gasifier and were sent on our way with no problems or additional paper work.  We did some research on the possible duty before we crossed and had concluded that the kit was duty free … nice to have that confirmed at the border!

Once we got the kit home the two drums of parts sat in the corner of the shop for over a month.  A few days ago I finally unpacked the two barrels … there are a lot of parts!  I purchased a GEK III V4.3, the most recent version that All Power Labs is building.  The fabrication/assembly instructions for these kits are on the internet.  As I unpacked I compared the parts in the barrel with a video from All Power Labs; the parts in the smaller barrel matched what was shown in the video, but the steel parts in the larger barrel were different in a few  cases … right now I am assuming that some changes to the parts have been made since the video was made.

After some emails with Julia Hasty (a technical specialist at All Power Labs), these are the instructions I am using for my project:

Based on the fabrication directions the first job I started was welding the gas cowling.  I suppose now would be a good time to admit that my welding skills are fairly basic … I’ve stick welded as part of running my business when a repair was required.  If the repair was too complicated or demanding (stainless, aluminum, cast …) I took the part into a welding shop.  So, this is the most challenging welding job I’ve taken on, and it is the first time I’ve used a MIG welder.  I picked up the welder second hand from a neighbour; it is a 250 amp machine and I can now say it works!  I spent a few days playing with the welder before starting … practicing on 1/16″ steel.  MIG welding seems a lot easier than using a stick welder as long as you remember to turn the gas on … I spent a puzzling couple of minutes trying to figure out why the welds were suddenly crappy … had to grind them off and start over!  The stitch function does not work on this welder so I have been stitch welding manually … a little tedious but not the end of the world.
I pretty much followed the second fabrication video from All Power Labs for the steps outlined below.
I started by welding the studs for the 4 support legs of the gasifier into the holes provided in the cowling.  This job was pretty simple … although a little challenging to weld inside the cowling.  You may notice that one of the welds in the picture to the left goes off track … I discovered that my auto-darkening helmet can be adjusted based on the amperage being drawn by the welder.  Less amps means you can reduce the darkness level.  Until I figured that one out I could barely see anything but the arc while I was welding … it made it hard to stay on track!  I am now very happy with the automatic helmet, I was getting ready to go back to the old helmet I was used to up to that point.

I then fitted and tack welded the bottom plate of the cowling.  The hardest part of this job wasfitting the plate, after every weld I would re-adjust the clamp to make sure there were no gaps between the wall and plate.  After the bottom plate was tacked I then tack welded the top flange … again I adjusted the clamps after every tack to take the gaps out between the wall and flange.  I then tack welded the seam of the cowling.  I clamped the seam together as I tacked to keep the seam tight.


 I then welded the ash port, gas out and a third unidentified (see later) assembly; each assembly consists of a hanger and plate.  Welding these assemblies together was straight forward, but I did have

problems with the gas out assembly.  The hanger for this assembly was too small for its intended cut out in the plate, leaving an air gap between the plate and the hanger along two sides and along the seam of the hanger.  I had trouble welding the seam of the hanger due to the large gap … I was just blowing out the steel.  I solved this problem by welding a 1/4″ round filler piece inside the seam.  I am guessing there is a more elegant solution, but this worked for my skill level!  I am also assuming that this filler will not be a problem for gas flow down the road.

At this point I am a little stuck on how to proceed as the video does not exactly match my parts.  I am wondering about the following:

    1. The gas cowling wall piece does not have a large diameter hole for a 1.5″ weld coupler.  It does have a larger square cut out that fits the third unidentified assembly I welded above.  I am assuming that this square assembly is a replacement for the weld coupler.
    2. The gas out assembly does not have a hole drilled in its hanger piece as is shown in the video.  I think this is fine as the assembly instructions for the v4.3 GEK mention that the bung has been moved from the gas out assembly.
    3. There are two 3/4″ diameter holes that have not been dealt with in the gas cowling.  
the video shows welding a male nipple into one of these holes for the manometer.  It does not show anything for the other hole that I have been able to figure out.  I do not seem to have a male nipple in the plumbing parts bag.  I am assuming I weld two of the the weld couplers that fit this diameter over these holes.


I am going to watch the next fabrication videos and see if I can find the answers to these questions before I finish welding the gas cowling.


Help me build a gasifier!

I have mentioned on a couple of occasions that my intention is to provide some of our home’s electricity using wood gasification.

Wood gasification is a process that enables you to run an internal combustion engine by burning wood, and we have tonnes of scrap wood.  We also plan to capture the waste heat from the gasifier to heat the house.  It is an interesting technology, and you can learn about it here or here.

One of the sites I follow announced a give-away of gasifier parts.  It is really simple!   To quote the site … ‘I’ve got an assortment of about $800 worth of laser cut parts and a rolled 16 ga. cylinder in mild steel that I am giving away for my birthday. THE BIG 32!  Whomever writes the
most commented blog or forum post will win these beauties.’

I’ve written the blog post (http://victorygasworks.ning.com/profiles/blogs/earthships-and-wood) … now I need comments.   Haven’t you ALWAYS wanted to build a gasifier!

I almost forgot.  Happy Birthday Ben!

Hey … what are you waiting for?