[Cob] cob w/adobe and other materials

[Dulane]

I think that although cob ovens can last a good long time, they are the most
practical/functional cob to start with, and a wonderfully organic project to
be part of. I think incorporating adobe would be a great design experiment. 

One of your most serious considerations is a roof. Don't even worry about
longevity unless you have a roof plan. Maybe just do it for the summer.

Don't use concrete mortar, or any material that will survive a deluge,
because it is just another chunk that will wind up in a land fill someday.

Don't be concerned if you lose your first oven to beginner's luck or
seasonal rain. You can always start anew, and probably use the same
materials.

When I built my oven, I had a person stop by who insisted that I empty out
the wet sand form and fire it within 3 days. Then I realized that they had
been to a 3 day workshop and they believed that cob ovens could only be
built quickly. Mine sat for a month before I fired it. No mold, no worries.

It dried nicely, but it still cracked eventually when I fired it. Nothing a
bit of sandy clay mortar couldn't fix. One consideration that I ran across
is that you need to have firewood cut to the size of your oven. My oven is a
bit small for regular length firewood, so I collect tree branches that I can
break/cut to size.

A cob oven is a gift project for people who are considering a larger
project. And good cheap fun too.