Introduction: Portable Wood Gasifier Stove Made Just From Cans
Here's a wood stove great for backpacking, camping or emergency. It's very portable and efficient, made from just empty food cans (no other material is needed). Fueled with leaves and twigs, the stove generates more than enough heat to fry, boil and otherwise cook for two or three. The stove weighs only 6 ounces and packs down to 4"×5".
Using a principle known as wood gasification (or pyrolyzation), the smoke is burned in an afterburner, thus creating the extra heat which makes this wood stove so efficient.
Twigs about ⅓" to ½" in diameter and about 1½" long work well. Once lit, it's important to feed it fuel on a regular basis. We find maybe three twigs or so per minute is optimal. It might need a little experience to get the "feel" for the right rate. The stove is quite insensitive to the type of wood used. We've fed it oak, cedar and yaupon twigs, scraps from woodwork, etc. Whichever fuel is used, it must be dry. After a while, it'll be necessary to empty the ash.
Full step-by-step construction details are given in the video.
Step 1: Watch the Video
Step 2: Materials and Tools
As shown in the picture (and video), four cans are needed with the approximate dimensions as given below:
- Outer Case - 4"x4¾"
- Fire Box - 3¼"x4½"
- Grill - 3"x5"
- Pot Stand - 4"x2"
Note: the pot stand can must "interlock" or fit inside the rim of the outer case can, thus preventing it from sliding off when a pot is placed upon it.
- try square with inch markings
- electric drill
- step bit with at least 1/4", 5/8" and 3/4" steps
- metal snips
- marking pen
During construction there is much metal cutting and drilling. Care should be taken to avoid cutting oneself. File down any and all sharp edges.
Step 3: Make the Outer Case
- Open the BOTTOM of the outer case can, empty the contents and clean.
- Outline the base of the fire box can on the TOP of the outer case can, draw a circle about ⅓" inside that outline and cut along the inside circle, removing the resulting disk.
- Make sixteen equally spaced radial cuts to the outline.
- Bend in the resulting tabs using the fire box can, but don't push it through.
- Drill eight ¾" diameter holes ½" above the BOTTOM, spaced evenly around the can.
Step 4: Make Fire Box and Assemble Stove Body
- Open the TOP of the fire box can, empty the contents and clean.
- File back the inner lip of the opening.
- Ensure the grill can fits through the opening.
- Drill eight 5/8" diameter holes 5/8" above the BOTTOM, evenly spaced around the can. Interleave eight ¼" diameter holes 1¼" above the BOTTOM. Drill sixteen ¼" diameter holes 5/8" below the top, evenly spaced around the can.
- Use the grill can to push the fire box can into the outer case, thus preventing the air holes from being crushed.
Step 5: Make and Insert Grill
- Open the TOP of the grill can, empty the contents and clean.
- Drill an array of many ¼" to ⅓" holes in the BOTTOM of the grill can, evenly spaced. Don't place them too close to one another.
- Drill six ¾" diameters ½" above the BOTTOM, spaced evenly around the can.
- Mark a line around the can 1" from the BOTTOM, and cut along it.
- Cut away the metal between three pairs of adjacent holes, leaving a grill with three equal spaced legs.
The grill should fit loosely in the fire box. Simply drop it in, legs down.
Step 6: Make the Pot Stand
- Open the TOP of the pot stand can, empty the contents and clean.
- Drill twelve ¾" diameter holes ½" below the TOP, spaced evenly around the can.
- On the BOTTOM, cut around the can about ⅓" inside the rim and remove the resulting disk.
- Between two of the holes, cut away the metal, leaving behind the TOP rim. This is the fuel port. Also, cut away ½" of the rim centered over the fuel port, permitting the pot stand to be squeezed slightly.
Step 7: Initial Preparation
Before using the stove, the plastic linings in the cans must be burned off. Fire up the stove and let it run at temperature for a few minutes. Then, once cooled, use a stick to remove any plastic ash in the gap between the outer case and fire box.
Step 8: Basic Use
- The pot stand is stowed in the base, between the outer case and fire box. It's inserted/removed by first squeezing it slightly.
- Fill the fire box with leaves/paper, topped with some twigs. Light.
- Once the flame is burning, place the pot stand on top of the stove, ensuring it interlocks with the outer case. It's ready to take a pot/pan/etc.
- Feed the stove two or three twigs per minute through the fuel port.
- When done, let the stove cool, shake out the ash (removing the grill if necessary) and re-stow the pot stand in the base.