In this post I’ll explain how I built my Mk II ammo can rocket stove. This is a small, inexpensive homemade wood stove which burns wood, without smoke, thanks to it’s secondary burn system. In this post and video I break the stove down and talk about how I made each component.
If you want to see this stove burning wood, without smoke, then check out this blog post.
Thanks to the feedback and comments from viewers (As well as the touching comment posted on this blog post by Tommy Cruz about him and his son Nicholas building an Ammo Can Stove together) I prioritised the build video for my Mk II Ammo Can Rocket Stove. I uploaded it as soon as I could and it is now live on YouTube.
The video details the following:
- The flue I explain how the flue is constructed and how I found a really easy way to attach it to the top of the ammo can. I then talk about options for the larger diameter flue section above the stove.
- The cooking surface / hot plate This prototype stove doesn’t have a cooking surface but I explain how you can create one really easily by simply removing the handle brackets. (Each bracket is retained by 4 small spot welds, so they are easily removed)
- The lid seal The stove rope seal around the interface of the stove lid and body.
- Turnbuckle door locks These enable the door to be locked shut extremely tightly by turning them 1/4 turn with a metal rod.
- The steel baffle This is an essential part of the stove as it directs the flow of gases during operation, reflects and retains heat within the burn chamber and creates the conditions necessary for secondary burn to take place.
- The secondary air system I explain how this draws in cold air from outside, pre-heats this air in the burn chamber, and then releases super-heated secondary air into the stove in the area just below the steel baffle. This secondary air reignites what would be smoke, eliminating this smoke via complete combustion. I explain how I made the secondary air system out of simple and cheap steel water pipes and fittings.
- The three insulated sides of the stove I used fibreglass insulation sandwiched between inner steel liners and the external skin of the ammo can. I insulated three sides and left the side with the door uninsulated. This provides enough insulation for a clean burn but also allows for great heat transfer out of the ‘front’ of the stove where the door is located.
- The stainless steel heat shield adjacent to the end of the baffle This is something I added to protect what I considered to be one of the most vulnerable parts of the stove. This area is where the flame and combustion gases change direction before heading across towards the flue. I thought that it would be prudent to add this spare stainless stell I had to protect this area. I also believe that it improves the stove by acting as a heat store, retaining and reflecting some of the heat back into the burn chamber.
- The stove door I explain how I made the stove door using stainless steel and a hinge, with mica for the viewing window. The mica is loosely held in position which allows for differential thermal expansion and contraction. As well as the previously mentioned turnbuckle door locks, the stove door also has a quarter turn door latch which I made by filing off a portion of a large headed screw and positioning it precisely below the opening I cut into the front face of the stove.
- The fuel raising grate This is simply made from some chicken wire but is essential as it allows all-round burning of the fuel.
- The insulated lower section of the stove This is where the fibreglass insulation is at its thickest (around 1/2″ or 12 mm). On top of this is a stainless steel plate to protect the bottom of the stove from glowing hot embers.
- The primary air intake / rocket stove intake This is a stainless steel 90 degree elbow I found lying around in the garage. It is where the primary air is drawn into the stove and can also be used to add fuel once the stove is up to temperature, without having open the door. This is a useful feature and I will be looking to improve it further on the Mk III.
I then talk about how you can help by making suggestions for improvements that I may go on to incorporate in the Mk III. I also mention a secret, much smaller, homemade stove that will be coming one day…
Anyway, back to the present: Watch my video ‘How I built my Ammo Can Rocket Stove – a small homemade wood stove (Mk II)‘ below:
You can buy these ammo cans here: https://amzn.to/2BkRDLl
These homemade wood stoves are very useful. I’ve had messages from people who want to use them for all kinds of purposes: A workshop in Northern Minnesota where winter temperatures of -36 degrees Celcius, refugee camps, preppers, hikers, tiny home dwellers… These little stoves seem to me to be very useful at plugging a gap in the market for a small, inexpensive, easy to build wood stove that anyone can build at home, without technical experience. I aim to help out as much as I can by making the Mk III really special.
Do you have any suggestions for the Mk III? Let me know what features you would add and anything you can think of to improve the stove. Your idea could be incorporated in to the Mk III (which I hope will become a very popular DIY stove!)
Please leave your comments below.
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