HI,

since both Mike and Lucy have mentioned they might attempt to build
adobe (or cob as we call it in UK) ovens I thought would be good if I
recorded some of lessons I have learnt from building and using mine.
All the points here are things additional to what is in the well known
book http://www.amazon.co.uk/Build-Your-O.../dp/096798467X
by Kiko Denzer (which you should definitely get if you want such an
oven)

Sand
eventually I have found sharp sand is the best to use in adobe mix.
Mostly I used builders sand which is OK but made mistake of using soft
sand on final 'decorative' layer of oven - thinking it would give a
smoother finish but result has been this layer is falling off in many
places - doesn't look good though fortunately doesn't really affect
operation. I then made one oven door from sharp sand cob mix and this
lasted very well considering the movement a door gets etc

People
unless you hire a mixer or something its really essential to assemble
group of people to puddle the mix (preferably people who don't mind
mud between the toes as doing this without shoes is actually best and
less mucky) and one or two others to do actual building. In my case we
had about five such oven building parties usually about six people so
some can be refreshign whilst others work. Quite easy to recruit with
promise of oven products etc

Form and template
Denzer advocates making a form out of sand on which to build the oven
dome which is fair enough. But quantity of sand required is a lot
(though it will get used in cob mix later) - I realised I could have
replaced the core of the form with something like lumps of polystrene,
but make sure you don't use something too big to get out of door hole
when you cut it. When you shape form its good to cut a template from
plywood etc that you can push around the outside of the form to make
sure its evenly shaped. Once you have finished form we made an
addition to Denzer instructions which I think is very useful unless
you are sure you will finish first layer same day. Denzer suggest
wrapping form in damp newspaper but we had idea of wrapping form in
cling film. This means both form sand can't dry out and get blown or
washed away and its easy to separate from side wall of oven when you
are ready to do this.

Temperature probe(s)
To some its heresy to add something high tech to such a
quintessentially low tech and ancient design as the cob oven but to me
I enjoy the combination. I was lucky to get on ebay infa red
temperature meter with socket for temperature probe and three probes
for the price of one probe http://www.etiltd.co.uk/raytemp_8.html. I
have one probe whose is just on inside surface of oven, one about half
way through oven wall and one at about 4" from outer surface. Inner
probe is good for pizza (I bake at around 350C - takes about 2 and
half minutes) but the one in middle of wall is the important one for
bread as it tells you whether you have got the heat stored in the oven
ready to start taking fire out of oven, baking etc. I take this probe
to around 285C before removing spreading and then removing fire. So if
you can only afford one probe have this middle one. Point at beginning
is that if you go for a probe it needs to be built in as oven is made,
very hard to install afterwards.

On probes I am sure if you are going to use oven really regularly and
all year etc you will work out more analogue ways, feel of heat on
hand etc to know when your oven is ready to bake but in my experience
cob ovens aren't used so regularly and not always by same baker so a
probe makes sense

Oven door way and chimney
I am quite firmly in favour of building like an igloo arrangement for
door way with chimney placed away from oven from where door will go
in. You can see on pics of my oven some smoke comes out front but the
majority goes up chimney and so out of yours and others faces/eyes.
Entrance tunnel should narrow like a plug hole towards oven as
undoubtedly both walls and door itself will wear down in use so door
will thus remain possible to get reasonably tight fit.

Oven pedestal height and/or baker's pit
your oven floor should be just a bit lower than shoulder height, you
can see this in virtually all bread oven designs apart from multi-
deck. This both facilitates keeping an eye on what is baking, loading
and unloading baked items and also you are not sticking your head in
any smoke coming out the front of oven when firing. You can either put
oven on pedestal or alternatively as I ended doing almost by
coincidence, dig a pit in front of oven that lowers the baker to right
height. In my case this pit was precisely where the clay for cob came
from and if you think about it there is liable to be less work digging
a pit if you can that volume of a pedestal for oven (but if you are
somewhere rocky maybe its totally another equation). For me pit also
helps separate actual baker from the pizza preparation people when we
are having pizza party + there is possibility to sit on edge of pit as
well as standing and still be in right position.

Oven door
this is one of the hardest things to work out. I started out with a
fairly soft wood door with a piece of tin on inside but the nails
attaching tin to wood quickly burnt holes in the wood and door fell
apart. Then I made a cob one as mentioned above, this had a network of
wire inside cob that in turn was attached to a wooden handle on
outside. This lasted quite well but eventually cracked around the wire
network. Now I found a good bit of oak, with tin covering inside
attached by bolts going through the wood to the outside of door so no
possibility of burning out. The door is soaked in a water tank before
use. Its showing every sign of lasting as long as rest of oven will. I
also use soaked rolled newspaper to block any holes between door and
oven entrance walls.

that's all I can think of at the moment

yours
Andy Forbes

On Tue, 18 Mar 2008 04:01:11 -0700 (PDT), atty
wrote:


Big Snip

that's all I can think of at the moment

yours
Andy Forbes





Hi Andy,

Well, all I can think of is to say "Thanks."

That was great...,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Great, informative post! Thanks, Andy.

Dusty

"atty" wrote in message
...
HI,

since both Mike and Lucy have mentioned they might attempt to build
adobe (or cob as we call it in UK) ovens I thought would be good if I
recorded some of lessons I have learnt from building and using mine.
All the points here are things additional to what is in the well known
book http://www.amazon.co.uk/Build-Your-O.../dp/096798467X
by Kiko Denzer (which you should definitely get if you want such an
oven)
....

atty wrote:


that's all I can think of at the moment

yours
Andy Forbes


Thanks for the info. That is a neat idea. We have been talking about
an outdoor oven at our next place for years and this one is a neat idea.
I have easy access to clay also. Gray clay where I live now and red
where I am going.

Mike
Some bread photos: http://www.mikeromain.shutterfly.com