Wood-gas Stove for the BPL Trapper mug Part 2

The other week I got a few more minutes to play with the stove designs in an attempt to get them to work a little more efficiently. I'll be getting less time over the next few months since Fall quarter of college starts on the 28th of September.

I took Prototype 1 and shortened the outer can by 1" to get the bottom of the burn box a little closer to the base of the stove and to see how it performs with getting the hot coals closer to the actual fire. Since they fall through the grate as they become ash. I also revised the mesh on the bottom of the burn box as I had previously intended. I used a 1/2" wire fence mesh from Home Depot, which was also used to make the pot support. I was tempted to get the 1/4" mesh... but I went with the standard 1/2" mesh for weight and the fact that is what it appears most stove builders use for pot stands as well. After cutting the bottom of the outer can, without my hydraulic press was fairly hard to get the base of the can to press neatly onto the can. I dented the outer can and partially crushed it... I straightened it back out with a pair of pliers and turned the lid inside out and worked it back onto the bottom of the out can. With some help of the pliers I managed to get everything to fit fairly snug back together.

The next model revision (prototype 2.0) I made was to use the same standard sized peach/soup can and use a Campbell Tomato Soup can for the inner fire box. Figuring it would allow me to use the full depth of the peaches can, by giving me an extra 1/2" of length and a 1/2" wider for the fire box. I took a different approach to the holes on this stove. Instead of marking to drill every 1" and using a 1/2" drill bit, which was than augured out to be ~ a 3/4" hole as I used on the original can... I marked ever half inch and drilled a 3/8" hole which I augured out to ~ a 1/2" hole. I figured I'd try more holes at a smaller size... I used a similar procedure as part 1 to make the burn box and installed the wire mesh and put the stove together.

The 1" cut mark for the the first prototype.
The start of prototype 2.0
The soup can nested into the peach can.
The old burn box next to the new burn box.
The cheesy wire grate before replacement in ver. 1.0, and the wire grate in ver. 2.0
The stoves side by side.
Testing... The new design smoldered a lot and I could barely get it to even get a couple minutes of good burn time... Which has been a fairly consistent problem with both designs, yet it was definitely amplified with this model. Some of it might be my choice of wood, but I think these stoves are slightly suffocating due to the small amount of ventilation and their small burn box size. Which gets full and I can see where O2 movement could be a problem. I need to play with the oxygen delivery systems on the inner can first, I think I'll add a couple holes lower on the burn box to help fuel the fire mid can. Prototype 1.1 burned a lot better, but I still had trouble getting a consistent burn, granted it was a little better.

Trapper mug, stove 1.1, stove 2.0
Stove 2.0 with the new pot stand.

The next plan is to do a little more research, and play with the O2 delivery (add a few holes to the inner can at a little lower level, and maybe some mods to the outer can holes as well). I might also cut down the tomato can to fit into the shorter can as well. I'm not going to give up quite yet, but I might reroute my design to a larger stove if I can't figure out a way to get this stove to burn better. There might just not be enough distance between the walls on the second stove... But only tinkering and testing will tell... Nothing like smelling like a camp fire at the end of the day!

Warning! Playing with fire and tools can be dangerous! This post is for informational purposes only. Using any of these methods, or using a fire, a stove or tools can cause health hazards, injury or death!!! Use this information at your own risk.