[Cob] Joe Kennedy comments on biochar in earth ovens

[john fordice]

Shawn / Joe,
There is a cast-able refractory material available from places that  
sell ceramics supplies.
Comes in a bag & mixes with water.  Cast in a form to your desired  
shape.
Makes a high temp insulate  material that is relatively light  
weight.  Would be a good way to make the
oven door
The rocket door for a cob oven is a nifty design ........  good thinking
john fordice
..............................

On Apr 26, 2011, at 4:16 PM, Shawn King wrote:

> Hi Joe, I like the plugs idea, easy to make from common raw material.
> I think a coil or snake of chicken wire and charcoal lowered/stuffed
> into the chimney might also work, and provide even more surface area.
> My chimney requires some reinforcement before I can try that idea.
>
> I think the vermiculite cob is a step up for the rocket door design.
> What I have works well, but the weight of the door arch is a nuisance.
>
> Great stuff all around!
>
> Shawn :)
>
> On Mon, Apr 25, 2011 at 5:39 PM, Joseph Kennedy
> <livingearth62 at hotmail.com> wrote:
>> Hi Shawn,
>>
>> I am thinking to create a biochar drawer that would fit in the  
>> lower slot of
>> your rocket door.  In my design, I think the gases would ignite,  
>> even though
>> the main fire will be in the chamber below.
>>
>> I like the carbon scrubber.  I am planning to make a chimney plug  
>> of a
>> ceramic flower pot filled with vermiculite cob.  I could use the  
>> same size
>> flower pot to form carbon plugs with chicken wire and biochar (i.e
>> charcoal).  I am also thinking of vermiculite cob to make the oven  
>> door per
>> your design.
>>
>> All the best,
>>
>> Joe
>>
>>> Date: Mon, 25 Apr 2011 16:48:39 -0700
>>> From: sbkingster at gmail.com
>>> To: livingearth62 at hotmail.com
>>> CC: coblist at deatech.com; albert at thefarm.org
>>> Subject: Re: [Cob] Joe Kennedy comments on biochar in earth ovens
>>>
>>> Joe and Ray,
>>>
>>> Hmmm, Joe, I like the drawer idea. I'll keep an eye out for an old
>>> popper, likely to work well and have a great vibe! I'm thinking heat
>>> loss would be a minimal issue as the heat is stored in the mass  
>>> walls,
>>> not in the air, so opening/closing won't cause much loss in most
>>> designs, unless you are also loosing a lot of mass wall area in the
>>> design. My oven "breaks the rules" as the door is wider than  
>>> would be
>>> considered optimal to allow use of an earthen crock for slow cooking
>>> stews after the bread/pizza etc. is done. It still works, but I  
>>> think
>>> I do loose a little efficiency by having a >50% door width rather  
>>> than
>>> the approx 1/3 recommended traditionally. Maybe the drawer could be
>>> built into a metal "rocket door" type retrofit, with the drawer
>>> sliding in above the rocket door tube.
>>>
>>> I'm not sure how air tight the biochar unit needs to be. The  
>>> canister
>>> is pretty well sealed except for the burner holes. This may be  
>>> key in
>>> getting combustion to stop on its own when the pyrolysis gasses are
>>> exhausted, a good feature IMHO.
>>>
>>> I need to get good data on the canister method on my next firing.
>>> Weight of the wood mass before and after char, some estimate of  
>>> volume
>>> as well, and maybe the length of time a can-full will burn gasses. I
>>> would also like to try bamboo from local sources as a biochar fill,
>>> see what happens. Our sycamores drop lots of small branch material
>>> every year, twigs may just be the easiest and most available thing,
>>> but I bet bamboo will make prettier charcoal.
>>>
>>> Another experiment I'd like to try is a crude charcoal filter built
>>> into the chimney, likely near the end, to filter out some of the  
>>> smoke
>>> that seems inevitable when you first fire up. Make your own filter
>>> charcoal! Could be something easy, a slot in the chimney for a  
>>> couple
>>> of layers of charcoal in wire cages - maybe those old wire smore
>>> cookers, or something of the like. Change the charcoal out
>>> frequently, and keep it loose in the cage for maximum air flow,
>>> causing the exhaust to roll over and around charcoal pieces. Even if
>>> you only got half of the soot and other smoke nasties out of the
>>> exhaust, it would be well worth it.
>>>
>>> Plenty left to do!
>>>
>>> On Mon, Apr 25, 2011 at 3:49 PM, Joseph Kennedy
>>> <livingearth62 at hotmail.com> wrote:
>>>> Dear Shawn and Ray,
>>>>
>>>> I am thinking of a biochar "cooker" that could be inserted like  
>>>> a drawer
>>>> into the firing chamber and easily slid out with not too much  
>>>> loss of
>>>> heat.
>>>> Maybe several interchangable drawers, like old 8-tracks that could
>>>> be slotted in and removed when the biochar is ready, with the  
>>>> biochar
>>>> removed as generated during the firing of the oven.  Or maybe  
>>>> like those
>>>> old
>>>> fashioned popcorn poppers used in fireplaces, now that would be  
>>>> a cool
>>>> use
>>>> of old tech!  Gotta find me one of those to try.  Biocharpopper.
>>>>
>>>> Mad science for all!
>>>>
>>>> Best,
>>>>
>>>> Joe
>>>>
>>>>> Date: Mon, 25 Apr 2011 12:47:55 -0700
>>>>> From: cobanation at yahoo.com
>>>>> To: sbkingster at gmail.com; coblist at deatech.com;
>>>>> livingearth62 at hotmail.com
>>>>> Subject: Re: [Cob] Joe Kennedy comments on biochar in earth ovens
>>>>>
>>>>> Dear Joe,
>>>>> We just launched the Dragon Pizza Oven and it was a smash hit.  
>>>>> We ran
>>>>> it
>>>>> for five straight houts and collected at the end only a half  
>>>>> cup of
>>>>> biochar.
>>>>>
>>>>> Regards,
>>>>> Ray
>>>>>
>>>>>
>>>>> The Great Challenges we now face as a species present the very
>>>>> opportunities that are giving birth to Ecological,  
>>>>> Psychological, and
>>>>> Spiritual Sustainability.
>>>>>
>>>>>
>>>>> --- On Mon, 4/25/11, Joseph Kennedy <livingearth62 at hotmail.com>  
>>>>> wrote:
>>>>>
>>>>>> From: Joseph Kennedy <livingearth62 at hotmail.com>
>>>>>> Subject: [Cob] Joe Kennedy comments on biochar in earth ovens
>>>>>> To: sbkingster at gmail.com, coblist at deatech.com
>>>>>> Date: Monday, April 25, 2011, 12:03 PM
>>>>>>
>>>>>> Dear Shawn,
>>>>>>
>>>>>> I have been inspired by your low-tech stuff, and am going
>>>>>> to integrate the door design into my new oven under
>>>>>> construction with high school students.
>>>>>>
>>>>>> However, it seems a waste to make biochar unless you are
>>>>>> using that heat to heat up the oven for other purposes.
>>>>>>
>>>>>> To me the ideal would be to make a biochar chamber below
>>>>>> the oven (like in Ray Cirino's example) to create efficient
>>>>>> heat and biochar at the same time.  Any ideas on this
>>>>>> option?  I can play around with this idea, since my
>>>>>> oven is still under construction.
>>>>>>
>>>>>> I love the mad science going on!
>>>>>>
>>>>>> All the best,
>>>>>>
>>>>>> Joe Kennedy
>>>>>>
>>>>>> PS.  I just published an article of my earth oven
>>>>>> odessey at Kiko Denzer's site.  It has the plans of my
>>>>>> latest oven.
>>>>>>
>>>>>>
>>>>>> http://www.handprintpress.com/ovens/an-earthen-oven-odyssey-by- 
>>>>>> joe-kennedy/
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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