Re: [pct-l] Jim Mayer's tuna can alcohol stove

[ROYROBIN@aol.com]

Jim writes:

<< I built a "Geritol" stove and wanted to compare notes with you.  I used a
 2oz "lobster spread" can as the fuel reservoir, and a 6oz tuna can for the
 outer "shell".  The 2oz can is 1" high....  Anyway, the new design definitely
 puts out more heat, but had some disconcerting properties as well.  The most
 disconcerting thing was the flames leaping up over and above the sides of the
 pot! >>

Well, the idea was to make a hotter machine!   I'm using a 0.9 liter pot, a
little smaller than yours.  I get flame around the sides some but not as high
as you describe.  Might try reducing the air flow by cutting only three tab
holes, or pushing the jacket down further on the burner.  However, less air
may only cause soot to form.  Or, more air (pull the jacket up a bit) might
help.  Hafta play with it.

<<In earlier tests, I got 4 min 30 seconds burn time out of 2 tablespoons of
 fuel with the Geritol design.  At that time I had bubbles breaking loose from
the
 bottom of the pot, but I wouldn't have called the water quite boiling yet.>>

My results were the same as yours, i.e., a good boil in about 5 minutes.
 
<< One final observation is that the "Geritol" design got going much faster
 than the open burner.  It took a minute or so for the open burner to really
 get going.  The "Geritol" stove looked to be going full blast in much less
 time than that. >>

It definitely gets up to speed faster and burns fuel at a higher rate.  The
idea is to get more calories per minute into the water.  If you halve the heat
input, it takes way more than twice as long to boil the water because the rate
of heat loss (which you're trying to overcome) doesn't change. This has to be
an advantage as long as you can get the lid off when you want to!  ;-)

I think you also asked whether the jacket can easily be removed from the
burner.  No, not easily.  The tabs catch the rim of the burner and keep the
jacket from slipping all the way off.  This is a plus in that it keeps
everything together.

Just had a thought about a "simmer" setting.  Maybe by pushing the jacket down
to restrict air flow....  Or push it down further to stop the flow entirely
(the wick material around the top of the burner would act as a kind of seal)
and put something over the central hole to put the thing out.  Have to try
that.  The burner/jacket unit could be kept in a plastic container with a
seal-top if it got to smelling things up in the pack.       

If I've pushed the right buttons, there should be a .jpg drawing of the tuna
can stove with my note to the list.  This has been a fun project and I'm
looking forward to using this stove on the trail this summer.  -- Roy

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