I was perusing the composite matierals in the Aircraft Spruce
catalog pages and noted that the fiberglass (and other ) cloths
are characterized by a unit weight, like 5.8 oz/square yard.
My naive assumption is that the cloth as purchased would,
on average, weigh 5.8 oz /square yd.

But some of the descriptions include a 'finished weight' which
is slightly different from the 'other' (nominal?) weight.

The weight of the final product after being impregnated with
resin and cured will vary with material and technique, but if
I assume an average specific gravity of about two for epoxy
fiberglass and use the nominal thickness of the cloth I compute
a weight of the resultant fiberglass sheet that is about twice
the 'finished weight'. So I'm assuming that 'finished' weight
does not refer to weight of a one square yard sheet of fiberglass
made from that cloth with epoxy or polyester resin.

So, can anyone enlighten me on what they do mean?

By 'finished' weight do they mean the actual average weight
as opposed to a nominal (rounded) value used to characterize
the cloth?

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FF