Backpacking wood stove redux (?)

In this blog entry I detail the evolution of my cool wood burning backpacking stove--that's not an oxymoron.  The two piece concept includes an upper section which serves as a pot support and a lower section that serves as the burning chamber.  One piece nests inside the other for compactness.  Assembly of the completed stove is simple:  one simply places the pot support on top of the burning chamber--simple gravity.  One achieves great stability by finding or creating a flat level surface for the stove.  

A year or two ago I read Mark Jurey's page about his Penny wood stove, a backpacker's wood burning stove made from a Marinara sauce can (4" diameter) three tent stakes and a wind screen.  

Jurey's stove

MyStove I.  I made a stove from a 20 ounce Dole Pineapple Chunks can, but didn't want to fuss with tent stakes.  It was OK with the wind screen/all its holes and the pot resting on the top about 0.75" above the burn chamber, but it smoked throughout the entire burn.  When I lifted the saucepan 1" higher, the smoke would burn off.  

MyStove I (left) and MyStove II

MyStove II.  I made another stove from a Trader Joe's Marinara sauce can, but lowered the top of the burn chamber so that the pot would rest 1.5" above.  It still smoked.  Maybe I needed to get used to the idea of smoke with a wood fired stove.

Hoping for a smokeless burn, I made Mark's Penny wood stove.  I couldn't get the thing not to flop over with tent stakes--I trashed the stove.  No pictures of this failure.

MyStove III.  I made a stove from a big 46 oz pineapple juice can.  

MyStove III.  Note the vent holes near the bottom.  I cut these vent holes only on the sides and the bottoms, making tabs that I bent up to support the elevated floor (made of hardware cloth) inside the burn chamber.  I also cut tab-style vent holes above the elevated floor to keep the floor from falling out when the stove isn't upright.

The pot rests on top about 2.5" above the burning chamber.  It's too big to take camping.  It's for home use only.  It weighs 4 oz.   It works well enough and smokes much less than my first wood stove.

I liked Mike Lancaster's no stake pot support seen on Mark's website.  

Mike Lancaster's no stake pot support 

I found cans at the grocer close enough in diameter to nest, and thought I'd make a stove with slots on one can and tabs on the other so that one would be the burning chamber and the other would lock into it and be the pot support.  I didn't construct this version because I thought I'd cut some of the parts improperly and end up with an unstable leaning stove.  

MyStove IVa.  I have reconfigured the wood burning stove, changing Mark's four piece stove (the basic unit plus three tent stakes) to a two part stove.  These two parts include a bottom burning chamber and a top pot support.  The concentric bumps on the bottom of a 5.5 oz aluminum cat food "interlocked" with the top of a Rosarita refried bean can (16 oz).  I built a

refried bean can stove with the cat food can on top to provide the pot support.  Both cans have the tops removed.  I cut away panels from the side of the cat food can to allow gas movement under the cooking vessel.  The cat food can has a large circle cut in the bottom to allow heat and combustion gases to rise--the cut leaves the part of the bottom that interlocks with the bean can.  The bean can has a hardware cloth bottom suspended 0.5" above the can bottom.  I removed 1" tall panels from the bean can leaving a 2.75" burning chamber.  The pot rests 2.5" above the burn chamber.  Its stability far surpasses that of the tent stakes in my attempt to make Mark's stove.

Stove IVa almost complete.

This shows the pot support with the bottom cut out enough for heat and gases to rise, leaving plenty to rest on the rim of the burning chamber below.

The burn chamber fits inside the pot support for compact storage inside a saucepan.

The bean can nests inside the cat food can and both fit easily inside a saucepan.  The bean/cat food stove weighs 51 gm.  Unknown:  the durability of the aluminum cat food can under high heat wood burning.  I will test soon.

TEST RESULTS:  Wood burning heat softened the aluminum cat food cat--as I watched, it buckled under the weight of the saucepan and 3 cups of water.  The take-home lesson:  Don't use thin gauge aluminum in a wood burning stove.

MyStove IVb.  This is MyStove IVa with a new pot stand using a water chestnut can (Asian food section of grocery store), which stands about 2 1/8" tall and spans 3.25" like the cat food can.  The pot stand rests on the burn chamber--attachment clips might consist of paper clips, if one felt the need.  A saucepan on top seemed very stable.  The setup is 6.375" tall, no higher than most canister stoves.  Any accident with this setup might topple the pot and probably the pot support and the burn chamber.
Pot support wt:  26 gm  Burning chamber wt.:  42 gm  
Total weight 68 gm=2 3/8 oz.
Mark's stove weighs 3 oz=about 85 gm, but also requires three tent stakes, which I can't use at the same time for my shelter.  The Ti stakes will weigh at least 6 gm each times 3= 18 gm.  Total weight=103 gm.

Test burn of MyStove IVb to follow.  

MyStove IVb

A MyStove IVb postscript:  One can use the pot stand on any burn chamber as long as one can keep it stable.  That achieves a burn chamber of 3.75" without progressing to MyStove V below.

Other options:  The double wall stove with a solid outer wall, a perforated inner wall, with both walls joining at the top and with the bottom of the outer can high enough to permit air to enter from below.  It's a can on top of another can.  The outside can directs hot air between the two cans back to the inside can, because the outside can's lid overlaps the top of the inside can.  Example of this below:  Norman Stoddard places an aluminum Foster's Premium Ale can over the top of his stove.  Putting a saucepan on the tent stake type pot supports is like having a hippo dance in point shoes, so I'd build this kind of stove with a short wide steel can on top.  

Norman Stoddard's Foster's Premium Stove

MyStove V.  A Campbell's Chunky soup can (18.6 oz.) fits closely over a Napoleon artichoke can (same size as Rosarita refried beans can) with ~2 mm to spare.  I can make a stove with a 4.5" tall burning chamber.  The cans nest to fit in a saucepan.

Nesting cans hoping to become MyStove V.

Constructions notes:
Tools included a Dremel tool with cut off discs, and a pair of needle nose pliers.  A sanding drum attachment for the former did wonders in keeping sharp edges to a minimum.
Materials:  Steel cans of various sizes will work, depending on what one wants for a burn chamber and a pot support.  I haven't looked for stainless steel, which would last and look pretty, but I want to see how steel does over time before I take that path.

Burn notes:

This is a top light system, that is, the fire begins on top, and burns down to the bottom.  In theory, I load the stove by placing little wooden sticks in the burn chamber, pencil box style, by which I mean that I see the ends of the sticks when looking down into the burn chamber.

The stove, loaded pencil box style

My most reliable start up begins with a capful (4-5ml) of denatured alcohol, using the cap from a 500 ml water bottle sprinkled on top of the wood.  That didn't work for the pencil box stack--most likely, operator error (expecting big sticks to burn instead of starting properly with small aticks).  It does work for loosely piled sticks.  I have lit wax paper under small sticks on top of the fuel load, but alcohol always works.  One method that has worked is to crumple a square of wax paper on the bottom, loosely pile small sticks on top & light from the bottom. Regular soft book matches do badly in the woods, not igniting or burning out right after ignition.  I like the stick matches.  If it appears that the fuel will run out before I've finished cooking, I keep feeding wood to the stove before it flames out.

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WARNING!!!
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Endorsement or recommendation of any equipment, supplies, services or techniques does not constitute a guaranty or warranty the equipment, supplies, services or techniques will function when needed.

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Use of gasoline, or any other petroleum products in these stoves may result in severe burns and/or death.