Going on cost .
Thr lightest " carbon fibre . dearest .
RFG . Second dearest .
Alloy , is not home made .
Steel , very few " blacksmiths " left to make a good prop .
Wood , even little boy's carve it, cheap enough to hang the dud-ones on the wall .
And to make a spare or two .
spacesailor
PS. : I would like a " Duralumin " ( German 1909 patent ) propeller.