There are plenty of aluminum can stove designs out there. This one is different in that it is not made from aluminum cans but rather from aluminum bottles (aluminum beer bottles to be specific) After building a few stoves myself I wanted to design one to address a few shortcomings of other can stoves:
1. Priming - A number of stoves require an external heat source to bring the alcohol to vaporization temperature. Some require heating the bottom for a few minutes or burning some alcohol in a separate "primer pan" or on the ground around the the can as a means to heat the exterior of the of the stove to achieve a self-sustaining burn.
2. Separate pot stands - A number of stoves have a low profile and are very compact however the smallest of the small require separate pot stands to cook with. Kind of defeats the purpose of a compact stove in my mind.
Sure there are side jetted designs that hold a pot however I wanted a design that would also address a third shortcoming.
3. Cold pan Flame-out - Of the can stove designs that do support a pot, I have seen them suffer from this condition. When a pan of cold water (fresh from the camp pump) is placed directly on a can stove, it acts as a large heat sink. Before the stove can warm the water, the cold pot cools the aluminum stove so much that it cannot maintain alcohol vaporization and the stove goes out.
Admittedly, there are are many great can stove designs out there; many are self priming (nothing new there) and some have integral pot stands. Each has pros and cons depending on your priorities. This is another design for consideration.
and besides, I just wanted an excuse to work with those cool aluminum beer bottles.
Update 9/15/09: Just posted an Instructable that that shows another stove related use for aluminum bottles http://www.instructables.com/id/Aluminum-Bottle-Tumbler-Cup-Cook-Pot/
Step 1: Aluminum Bottles
I prefer the use of these aluminum bottles over the traditional aluminum cans for the following reasons:
1. Stability - The overall diameter of a can is larger than a bottle, however, the bottles have a larger diameter where it counts, at the base were it contacts the ground. The wider base is important because we are making a stove to support a pot and every bit of width helps to prevent tipping.
2. Heavier Gauge - The bottles are a thicker gauge aluminum. The thicker metal is a little more challenging to work with (you can't cut it with a utility knife) however it brings a solid, durable feel that you just don't get from a can.
This also means more thermal mass to help counter the "cold pot flame-out" syndrome.
(Sure more metal is more weight however once you step away from a propane grill; a quarter of an ounce here or there is not my biggest priority. (By the way, don't forget to add the weight of a separate pot stand to those other designs)
The last photo show some of my trials with earlier aluminum bottle designs.
Step 2: Construction Section
No glue or epoxy
No flux capacitors...
The assembly is all press fit together. The cross section below shows the naming conventions for each of the four parts referenced in the following steps
Step 3: Bottom Cuts
I found that because to the thicker aluminum, the bottles could not be cut easily with a utility knife.
A hack saw works well to make the cuts.
The fixture shown below helped to start the cuts and made sure they were straight around the can. Several turns with the blade pressed against the can started the cut; which was finished by carefully sawing around the outside of the can with a hack saw. (do not try to cut straight through the can as the blade will bend the edges of the can once it breaks through the skin.)
2. Finish the edge of the can to remove any sharp edges or nicks. Any nicks at the edge will initiate a split when the can is stretched.
Place emery cloth (sand paper for metal) on a flat surface. Place the entire edge of the bottle flat on the emery cloth and turn the bottle to evenly smooth the edge.
Step 4: Cut Burn Bowl
1. Cut off the neck of one bottle. The cut should be at the tangent where the bottle neck just reaches full diameter.
2. Make a second cut at the top of the bottle opening as shown. This location is approximate. Start out with the cut a little long. it will be adjusted when fitting the burn bowl to the jet deck in step 8.
3. Smooth the edges as before.
Step 5: Jet Deck
2. With a file enlarge the hole to about 1 5/16" diameter (or a little smaller to leave room to tune)
3. This opening will need be tuned to create a force fit to the neck of the Burn Bowl
4. Drill (8) eight 1/16" diameter holes evenly spaced along the ridge of the bottle bottom. These are the jet holes
Step 6: Widen base
I used a 1.5" diameter PVC pipe fitting to widen the aluminum "cup". Place the PVC pipe in the cup and by angeling the cup while pulling, the cup is "rolled" off the pipe. This is done repeatedly rotating the cup a few degrees each time to gradually increase the diameter of the cup.
Be careful not to "flare" the edge of the cup. You do not want to create a "lip" on the edge. The goal is to increase the whole diameter of the cup to slide tightly over the outside of the Jet Deck.
Step 7: Telescope Jet Deck to Base
2. Press evenly to fully set the Jet Deck to to bottom of the base. You may need to place a board over the assembly and use a hammer to finish stretching the base to fully seat the Jet Deck.
Be careful to force the two pieces together evenly. They need to be aligned or the side wall of the Base could split or the side wall of the Jet Deck could crease.
Step 8: Assembly
It should be a tight force fit without gaps. Also the narrow end of the Burn Bowl neck should be touching the bottom of the Base so do not remove too much material at once.
Step 9: Colonnade
At this point use emery cloth and steel wool to remove the paint (if you like the bare metal look). It is easier now before all the openings are cut.
1. Widen the opening of the remaining 1.5" tall bottom.
Only widen the first 1/2" of the opening so that it just fits tightly over the Jet Deck.
2. Drill a hole in the center of the bottom and widen it as described in step 5 however this hole is wider. Make it about 1.75" in diameter ( widen the hole to remove the "dish" in the bottom - just to the ridge at the edge.)
3. Cutout (8) openings in the side walls to form the Colonnade. These openings are approximately 0.5" wide by 0.75" tall. (Make sure they line up with the jet hole in the Jet Deck)
I could not find an easy way to make these openings. I started with a few drill holes and widened with a file from there.
4. Assemble the Colonnade over the Burn Bowl and press the bottom opening of the Colonnade over the top of the jet deck.
Note: the Colonnade should press tightly down on the top of the Burn Bowl. it bottoms out on the top of the base prematurely, material may need to be removed from the bottom of the Colonnade to allow it to seat down far enough on the Jet Deck. The goal is to clamp the burn bowl into the opening in the Jet Deck.
Step 10: Time to Cook
Safety note: Never use petroleum based fuels in this type stove. There explosive nature make them unsuitable for this type stove.
Pour the alcohol in the burn bowl and light.
After about 30 seconds the stove is hot enough to vaporize the alcohol and ignite the jets.
At this point the pot can be placed on top of the stove.
The jets will heat both the pot and the stove.
This continuous heating of the outside of the burn bowl is what keeps this stove lit when a cold pot is placed on it.
Make an option cap from another can bottom and then you can store a canister of fuel in the stove for transport.