[Cob] Metal and Cob

[Bernhard Masterson]

I have two concerns with metal and cob.  First, moisture (as vapor) in the wall will condense on the metal creating wet spots and rust.

Second, is that they have different coefficients of thermal expansion.   Metal moves substantially with heat and cob is quite stable.  I have seen this as problem around the drums of rocket stoves.  I have also heard of this being a problem in earthen ovens where some builders felt they needed to use re-mesh.  But they were complaining that they didn't hold up and my belief is their short durability was because of the metal expanding and contracting with each firing basically causing the ovens to self-destruct.  These examples are with temperature differences of hundreds of degrees.  Perhaps thermal expansion won't be a problem at ambient temperatures.

- Bernhard 



Get under a sustainable lifestyle umbrella, the carbon is going to hit the fan.

____________________________________http://bernhardmasterson.com

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