Cob: [Fwd: Cob Masonry Heater]

[Darel Henman]

On the cuff I think that rocks, bricks, and fire grade cement would be
better for heating applications.

Cob will not heat as fast or conduct heat as fast as the above
materials.  The hot air will not be transfered into the house as fast
and will go up out of the house.  The reason for this is the cob is not
as dense as masonary materials.

Cob looks nice, but in this application I think performance should be
the issue.

Will you be bending the heat exhaust flow through a thermally massive
heater to collect and store the heat for latter even after the fire goes
out.

If you don't have an direct air intake for burning, the fire will pull
outside cold outside air in.  This reduces your objective of heating the
air in the house.

I don't know what refractory sand is, but diatomaceous earth made bricks
and also fire bricks would work for the hot inner core areas I have
seen.

Darel


Chuck & Linda wrote:
> 
> I too am thinking that I will be building a cob hybrid masonry heater. I
> will probably use the Finish design from Albie at Maine Wood Heat. I will
> probably bite the environmental bullet and put in a refractory inner core
> for the firing chamber as the temperture is really intense and I don't want
> to redo it in 3 years because the cob didn't hold up under repeated firing.
> Then I will construct the outer facing with cob as well as build the chimney
> chambers with cob which operate under less stress compared to the firing
> chamber. I plan on using a cook stove format with a heated bench and then a
> chimney. I will drop in an electrical stove top right next to the wood heat
> plate which may be soap stone.
> 
> In speaking with Norbert Senf, he said this would work as long as we use
> high quality clay and refractory sand.  This should result all in all with a
> high performing multi-purpose heater (which we take seriously in Wisconsin)
> at a moderate price.
> 
> Chuck Learned in Wisconsin
> Helping Hands Coordinator
> 
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.273 / Virus Database: 143 - Release Date: 8/16/01