N. Taylor : Here on the East Coast there is no collective history of
Cob or Adobe` and the best finish plasterer I know trained his eye and hand working untold 1,000s
of hours working with bondo, Skill and knowledge is where you Find it !
I have two ideas for you, I did a google search here in Permies for
Making Cob Test Bricks and immediately found pay dirt ! A second very good resource is ;
The Hand-Sculpted-House, Ianto Evans et all, you may be able to get it through your
local lending library, my copy came second hand from Amazon I think
or go to the source
Cobcottage.com
Consider everything you have done 'till now practice! In a well built, monolithic
Rocket Mass Heater RMH, it is the Mass and the Cob that holds the combustion core
together!
We can test fire with dry stacked bricks just to prove to ourselves that fire can bun sideways ! Wetting the bricks,then coating them with clay slip will create a better
seal,It is possible to do this for your first outdoor test and then gently knock the bricks a part, all the cleaning they will require is rubbing two bricks together !
However, this merely shows you that the job of your Cob mortar is not to hold the bricks together, but far
enough apart to deal with the bricks surface imperfections
and to build level and plumb,
course by course, ! YourHeat Riser deserves a cob mortar made out of fire clay and builders sand!
If you are really interested, the better grade of stoneware have various materials added to retard expansion and contraction! This
class of materials is called 'Grog'
One type of amendment is finely ground bone, many people who no nothing about china Know that 'Bone China' is good, without ever knowing or caring why !
If you are not learning, you are ready for that long 'dirt nap' ! Hope this was helpful and timely! For the Good of the Craft ! Big AL