Sunday, July 24, 2005

Making of a penny alcohol stove

Making of a penny alcohol stove - #2 Posted by Picasa

This weekend was perfect for making the penny alcohol stove mentioned in my equipmentlist in an erlier post: Friday was binge time. I rarely touch alcohol, so drinking six Heineken gave me a pleseant surprise. I needed this many cans to be sure I could experiment a bit.

On saturday morning I went to buy a couple of scissors and a hole cutter at Biltema. I went to work and made the parts necessary in the workshop using scissors and a vertical drill. The parts were made according to the origial plan, but the hole cutter was meant for cutting leather and such so I was unable to make the holes at the sides of the burner part. I am not sure why the folds on the burner was necessary to make. Perhaps it was to make it easier to fit. I felt I had no problem with that, but the first stove was made using the folds. According to the instructions: "A hole punch was used to make holes in the folds to release hot gases to the inside of the burner". I guess that gases vaporized and trapped under the folds could give the stove an extra burst so I will include them if I make the folds in the future. The first prototype is shown on the picture to the right.

Parallel to making the first prototype I made a second one using only a nail, scissors and a screwdriver. The original plans uses Heineken cans. I felt that this was not necessary if I didn't need a simmer ring. For full boost and without the top/bottom you only need two cans of any type (beer/soda, large/small). Standards cans need the folds to be able to push the burner into the fuel cup. It is also easier to get the right dimensions when using Heineken cans due to the bands. The second prototype shown to the left had a smaller filler hole and larger burner holes.

The third prototype was made with Heineken cans, but only using a swiss knife (scissors, screwdriver, pliers, knife). The filler hole was smaller than the standard, but the burner holes where similar. I was able to make some ok holes in the folds for this prototype. The prototype is shown in the middle.

All prototypes used a norwegian 50 øre instead of a penny. The coin is a bit smaller than the penny.

Burner tests:
The first stove performed great with a pot on top. Without the pot the flames seemed a bit red/yellowish. The priming time seemed ok for the liquid to start vaporize. All the holes seem to be of perfect size. Perhaps it would perform even better with holes in the folds.

The second stove had to long priming time due to the smaller filler hole. The bigger burner holes resulted in inefficient burning of much fuel in the priming. After priming the flames seemed even more yellow/red and a lot higher than for the first. This seems inneficient.

The third stove had a very long priming time due to the smallest filler hole. After the priming it seemed to perform similar to the first prototype, which is great.

Conclusions: The original layout seem to have the best hole sizes. It is possible though to make it with much more portable equipment. It is not necessary to use Heineken cans if you make shrink folds with holes.

The tests were cool - I will try to make at least a fourth prototype using portable equipment. For the next prototype I will use a message board type needle to make the holes and a small scissor. The needle seem perfect for the small burner holes. For the filler hole and the gas evacuation holes I will use multiple perforations instead. I am thinking of using the middle section of large cans to make a pot stand and a wind shield. You will then only need to bring a sixpack of beer (large cans), the needle and the scissors. If you are still interested in eating after drinking those cans you can also bring some food ;-)