Tanzania/Canada

[dmun]

I am still going with this plan which will put my first coarse at approx. 5 1/2 inches high.

Yes, this is perfectly sound. Some people cut the bricks in half on an angle to match the tilt of the first course of flat bricks.

[AndrewL]

Hey,
Great thread. Wish I had found the discussion earlier,... I have seen glass bottles used to insulate hearths for cob ovens. You might consider using bottles to insulate your dome?
Hope it's going well.
A.

[david s]

Be careful with the bottles for insulation idea around the dome. There is a chance that with all the moisture around them they could explode with steam pressure. I think that is why the glass is usually crushed for under floor insulation. If you have access to that pumice it should work pretty well if you crush it up and add 1 part cement for every 10 parts pumice, using it much like vermiculite.I'd guess you'd need about a 5" layer.

[david s]

Steve,
I missed your reference to filling the brick cavities with sand in an attempt to increase their density. Although sand is quite heavy it is a poor conductor of heat (K value 0.15_0.25) This is because of all the airspaces surrounding the grains of sand. You d to fill these, probably with an equal amount of clay or maybe that anthills. Then it becomes a good conductor with a K value like brick (1.3)

[SteveS]

Hello All,

I am continuing this thread in OVEN CONSTRUCTION where I probably should have started it in the first place. I had hoped to move the whole thread there but wasn't able to get help on that one (might not be permitted I guess). I have posted some updated pictures of my progress there and asked for some more advice. So sorry for any inconvience with the move!

Cheers, SteveS.