well I've made a few pieces from a trashcan, others from plexi-glas and a bunch of the pvc sheets... and well it's ok, but it doesn't have the right curve and none of the sheet stuff will ever have that.
only vac vormed or fiberglas pieces can have the right curves...
the thing with the sheet stuff, weither it is metal, pvc, sintra or plexiglas is, is that you can't wrap a sheet of paper around a football without fold lines if you know what I mean... Fett's armor is curved both horizontal as well as vertical.
Not that sintra, pvc etc armor looks bad, a decent paint job can make even cardboard armor look impressive.
the right curve does fit the body a little better though...