Author Topic: Penny Stove...  (Read 5045 times)

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Offline popeyespal

Penny Stove...
« on: January 29, 2011, 09:22:35 pm »
After six efforts that worked, but were far from perfect, I finally got a penny stove design all put together and I love it. I can boil a liter of water in just under 12 minutes although that is FAR more water than I should need. Reheating a can of beans or fixing Raman takes less than 5 minutes.

The stove burns Isopropyl Alcohol and I have tested it with both 70% and 90%. The lower percentage works and is a bit cheaper but does not burn as hot and so takes a bit longer. Not an issue for me but I will carry the 90% HEAT as a fuel source. Six meals worth of fuels costs less than $2.

The stove itself is the diameter of a pop can and about 2 inches tall and sits inside of another can that acts as windscreen, cooking rack and storage. I painted the screen/rack with Krylon black stove paint. The whole set-up is six inches tall and weighs less than 5 ounces. Perfect.

And is sitting on a Rubbermaid box. I can cook a meal...blow out the flame and handle the stove with my bare hands. The heat funnels straight up and is not wasted on the stove itself.

Offline DaveB

Re: Penny Stove...
« Reply #1 on: January 30, 2011, 12:45:04 pm »
Isopropanol (Isopropyl Alcohol) that you buy as 70% or 90% in a drugstore is expensive because it's a medical grade product and is very inefficient as a fuel.  The 10% water in the 90% grade reduces it's heating value by more than just the dilution factor.  A significant part of the heat content goes to evaporate that water to steam.  The 70% is far less efficient for the same reasons.

Try using denatured ethanol as your fuel.  It's cheap and available anywhere paint is sold and is anhydrous so there is no water to dilute it or waste heat.

BTW, 12 minutes to boil a liter of water is an eternity compared to most camping stoves using white gas or prpoane/butane cannisters.

Offline knolltop

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Re: Penny Stove...
« Reply #2 on: January 30, 2011, 02:01:11 pm »
Yes, alcohol fuel does take much longer to boil/heat/fry than other fuels.  But is no matter to me as there's plenty to do during that time.

Popeye ... there's ways to make your kit even smaller.  Could sub pc of alum as windscreen ... folds/rolls down to virtually nuttin.  Course ya gotta make pot support out of wire mesh.  I made my stove from the small V8 juice cans.  So now stove/6oz bottle fuel, pot support, & windscreen easily fit into a cutdown Pringles can (I keep bottle of Heat in separate place in bags).

My cook setup boils 2 cups tap water in 12 min in the house with 3 tsp of fuel.

Here's stove, pot support, & my pot ... with bottle of Heet for scaling purpose.

Here's with windscreen in place.
+-+ Michael +-+