Re: Aluminum griddles...

[Harmon Seaver <hseaver@cybershamanix.com>]

On Fri, Aug 30, 2002 at 08:00:49AM -0600, Tom Reed wrote:
> Dear Stuart and ALL:
> 
> Not surprised at the warping of 1/8" steel plates.  The problem is that
> local heat causes expansion before the whole griddle can get hot.
> 
> you might think that aluminum would not be suitable for a griddle, but lets
> think about it.  Lots of pots and pans in the U.S. are aluminum.  It
> conducts heat about 10-X the rate of steel (20 X stainless), so that it gets
> hot all over and might not warp in moderte thickness.  It is MUCH easier to
> cast than steel (Melting Point 650 C vs 1450 C).

   Yes, but it's not hard to melt an aluminum pot if it's empty. I would expect
an aluminum griddle to melt as well, or at least began to sag or burn thru in
spots. Also it's a bad idea, healthwise, to use aluminum to cook with -- one of
the suspected causes in the rise of Alzheimers is aluminum cookware.

> 
> While aluminum is more expensive than steel, there is a lot of low value
> scrap around the U.S., and maybe elsewhere.
> 
> Don't use Al for chimney pipe however, as it will definitely melt with a hot
> fire.  The secret to cheap chimneys in the U.S. is thin gauge metal (usually
> blued or galvanized)

  As I think either Ron or Dean mentioned before, you can't use galvanized metal
in stoves or chimneys, it gives off toxic vapours. Galvanized stove pipe is
meant only for low-temp gas heater vents. 

> with the edges crimped for assembly on site.  Can be
> shipped in nested bundles. One end is crimped so that the 3 foot lengths can
> be extended to 6, 9, ft etc.  Should last indefinitely if made large enough
> so that the 3-6 kW rocket fire doesn't raise above 600C (less than red heat
> in the dark).  Too small a chimney will get too hot; too large won't draw.
> 
> Keep testing ...
> 
> Yours truly,                TOM REED         BEF STOVEWORKS
> ----- Original Message -----
> From: "Stuart Conway" <stuart@treeswaterpeople.org>
> To: "Dean Still" <dstill@epud.net>; "ethos" <ethos@vrac.iastate.edu>
> Cc: <cindy@treeswaterpeople.org>; "Richard Fox" <twp@treeswaterpeople.org>
> Sent: Monday, August 26, 2002 5:31 PM
> Subject: [ethos] Re: Stove Update and Research Needs
> 
> 
> > Hi Dean et al,
> >
> > I agree that we as a group need to do more to expand our stove research
> and
> > building efforts. The health effects from indoor and outdoor pollution, as
> > highlighted in Asia recently, are a dire warning of worse to come unless
> we as a
> > group do all that we can now. That includes reaching out to other
> organizations
> > who might be able to either fund our work or do stove projects themselves.
> I met
> > recently with staff of PROJECT CONCERN in El Salvador who are interested
> in
> > collaborating with us to build more stoves in that country. Reaching out
> and
> > training other big NGOs like CARE, Catholic Relief Services, and others
> would
> > help to build more stoves and help more people.  in many cases, NGOs
> working in
> > Latin America are still building LORENA type stoves in their projects. We
> need
> > to make them aware of the new generation of fuel efficient stoves that are
> > available. Why waste resources?
> >
> > I just wanted to point out a few areas of concern on the Justa and
> EcoStoves and
> > to point out areas that need more research, based on my recent trip to
> visit our
> > stove projects in Guatemala, Honduras, Nicaragua and El Salvador. The
> planchas
> > or griddles that we are building on the Justa stoves and EcoStoves are
> still a
> > problem. The 1/8" steel that we are currently using has a tendency to
> warp. When
> > the griddles start to warp upwards, we are having our stove builders stand
> on
> > the griddle the first time that the stove is being fired up. That helps to
> > contain the warping. However, that is not a good long-term solution.
> >
> > PROLENA in Nicaragua has been building a circular 3/8 - 1/4" thick 5 -6"
> > diameter metal piece that they have been welding onto the bottom of the
> griddle.
> > The flame hits the circular addition attached to the griddle and extends
> the
> > life of the griddle. In this case, the stove owner just replaces the
> circular
> > piece when it burns out instead of replacing the whole griddle. PROLENA
> has also
> > reinforced the griddle with angle iron. In spite of these adaptations,
> PROLENA
> > staff are not satisfied with the griddles and are starting to test using
> cast
> > iron. Using cast iron for the griddle of course increases the cost and the
> > weight of the stoves, but would last much longer. As you know, we are
> trying to
> > keep the costs of the stoves low, so that more people can afford to buy
> them.
> > So, cost is definitely an issue in any of the proposed solutions.
> >
> > As Larry has pointed out previously, the 4" diameter chimneys that are
> made of
> > galvanized steel also have a limited life span. The longevity of the
> chimney
> > depends on how often the women is using her stove and how well she
> > maintains/cleans her chimney. Dona Justa has been using her stove for 3+
> years
> > now, and has the same chimney. However, women who make and sell tortillas
> will
> > have to replace their chimneys sooner, due to higher rates of usage. As
> long as
> > the chimneys are available locally, women/families can just purchase and
> replace
> > their chimneys as needed. In more remote rural areas, buying spare chimney
> parts
> > can be difficult. So, the chimneys are another area of where further R & D
> would
> > be helpful.
> >
> > The last area of concern is the Rocket elbow, the combustion chamber of
> the
> > stove. The hand made ceramic elbows have been holding up fairly well so
> far,
> > altough PROLENA and AHDESA in Honduras both report some problems with
> breakage
> > if the women jam in the firewood too far or too hard. Mostly, the problem
> has
> > been that a high quality clay is needed to withstand the heat, so that
> sources
> > for the Rocket elbows in each country are limited. The high costs of
> tranport
> > and breakage in route are drawbacks. In Honduras, using wood ash for
> insulation
> > is working all right, but has maintenance and performance issues, as the
> level
> > of the wood ash needs to be maintained or the stoves lose some of their
> fuel
> > efficiency.  So, improved models of the Rocket elbows would be a welcome
> > addition. Aprovecho is currrently working on a some experimental models
> with
> > refractory cement and other materials. I encourage the effort.
> >
> > Stuart Conway
> > Trees, Water & People
> >
> > Dean Still wrote:
> >
> > > Dear ETHOS,
> > >
> > > Hearing about clouds of bad air in Asia, killing untold thousands of
> people,
> > > caused in part by cooking stoves, wood burning in general, reinforces
> for me
> > > that we already know that even a simple, inexpensive combustion chamber,
> > > like the Rocket,  can decrease pollution. We need to inform people, find
> > > easier, more practical ways to build many stoves, create insulative
> bricks,
> > > etc.
> > >
> > > This report also lends a real sense of urgency to our efforts to learn
> how
> > > to burn biomass as cleanly as possible. Only a few people are working on
> > > this problem! The answer must be practical, easy for governments, aid
> > > agencies to adapt, easy to teach, and liked by the user.
> > >
> > > We are getting closer every year. The Ecostove, the HELPS stove, the
> Chiapas
> > > Rocket, the double burner South African Rocket, 2 burner stoves, are all
> > > great stoves. But hearing that such a serious problem exists in Asia
> > > certainly reinforces the seriosness of our quest: to invent,
> disseminate,
> > > improve stoves.
> > >
> > >  We are in a position of responsibility and I can't think of anyone in
> the
> > > world who is in a better position to help than us.
> > >
> > > Kind of scary...
> > >
> > > Best,
> > >
> > > Dean
> > > -----Original Message-----
> > > From: Rogerio Miranda <rmiranda@entelnet.bo>
> > > To: stuart@treeswaterpeople.org <stuart@treeswaterpeople.org>;
> > > dstill@epud.net <dstill@epud.net>; ronallarson@qwest.net
> > > <ronallarson@qwest.net>
> > > Date: Monday, August 12, 2002 8:51 PM
> > > Subject: ecostove on BBC
> > >
> > > >Hi Stuart, Ron and Dean: I was surprise tonite when I saw myself on BBC
> > > >World news (Earth Report). I was expecting some notice from the TVE(the
> > > >documentary agency), but it seems that they forgot to tell me. Anyway,
> if
> > > >you have a chance to see BBC Earth report today, perhaps they will
> replay
> > > >the documentary. It is a bout children  exposed to hazard
> > > >environment  conditions, and the last part include Ecostove. I will try
> to
> > > >get hold of a copy and share with you.  Good timing, when every news
> agency
> > > >is reporting about the brown cloud over South Asia.
> > > >
> > > >Go rocket stove.
> > > >
> > > >Rogerio
> > > >
> > > >
> > > >
> >
> >
> >
> 
> 
> 
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-- 
Harmon Seaver	
CyberShamanix
http://www.cybershamanix.com

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