Flat panels are necessary when making many types of solar
cookers. These panels are normally made from cardboard, wood, or
metal. The panels are covered with reflective material. This
page serves to discuss other possibilities. See also
Waterproofing. Parabola with paper mache:[Low cust parabola in
PlenoSol] Papercrete is a recently developed construction
material which consists of re-pulped paper fiber with Portland
cement or clay and/or other soil added. First patented in 1928,
it has been revived since the 1980s. Although perceived as an
environmentally friendly material due to the significant
recycled content, this is offset by the presence of cement. The
material lacks standardisation, and proper use therefore
requires care and experience. Eric Patterson and Mike McCain,
who have been ascribed with independently "inventing" papercrete
(they called it "padobe" and "fibrous cement"), have both
contributed considerably to research into machinery to make it
and ways of using it for building. Its R-value is r