Tac , I got it at the Art supply store ... a thin solid cardboard (not corrugated) about 10 X as thick as Kraft paper ... same color , lots stiffer ... About $1.50 / sheet... much like the back cardboard of a writing tablet (probably the same stuff)... Glues well , east to work , and we’ll be priming it and painting over it later ... the inner skin .... just think of it as a wood product , treat it like wood ... made of essentially the same stuff (cellulose) ... With a generous and thorough coat of TB2 on the back and gripper and paint on the front , we expect it to be around a long time ...

Plywood , even the thinnest , would be too Heavy and expensive , and difficult to work with ... canvas or a fabric would have showed the kerfing underneath ... this stuff worked out perfect ... and Thrifty too ...
