[Stoves] Crispin´s kiln

[Crispin Pemberton-Pigott]

Dear Paul and All

I have been quieter than usual about the topic because I am wrapping up 3
weeks in China with my wife twins and soon the nose must hit the grindstone
again.

>Tom, your calculations are very helpful.  I will be thinking (and possible
>testing) larger units, and then have 2 or 3 firing the kiln to get the
>necessary power.

There is an unused 1.3 M^3 kiln at Ceramic Arte which I am thinking of
tossing because it will have to be rebuilt to quite some extent and all the
elements would have to be replaced anyway.  I think it would hold about
50-60 stoves depending on how the shelving fits in.  Originally it had a
cart-on-rails to load and unload.

It is ideal for testing because it looks as if it might have been a gas
furnace in the past, changed to electric based on the hood over it.

Guys, I really appreciate the thoughts on this, especially Kevin, AJH, Tom
and Paul.  The math looks good and the economics look good.  I am wondering
how available Manny is because it always pays to start with people who have
professional experience.

With specific reference to Mozambique, there is a lot of biomass available
because for three decades many farms were abandoned during the war and there
are 30 years' growth of trees all over. Therefore I think it is reasonable
to use that fuel instead of burning coal to make stoves.

I need to point out that I do not need 1300 degrees. There is a little
confusion over the 'needed temperature' and the 'temperature of the fire to
get the needed temperature'.

The required temperature is Cone 3) which is 1168 (p.s. not Cone 03, if you
are looking it up.  I understand that a flame temperature of 1300 will
achieve that (readily?).

In my opinion having a lower temperature flame is better because it will be
harder to melt the stoves, which are very close to the melting point when
they are finished.  Though many of the ingredients melt at different
temperatures on the way to 1170, by the time 1170 is reached, the stoves and
grates are quite soft.  For example the upturned conical grate will sag over
the edge of a shelf if it is overhanging.  The material sticks to the
shelves extremely well and has to have a separating compound or a thin
circle of stainless steel under each part.

I am hoping for better circulation, faster temperature ramping and faster
charcoal burnout using gas.

Regards
Crispin