Hi Gazou, some decades ago I made one of these machines and made my own skirts [ no-no-I'm NOT a cross-dresser! ] using a rather open weave fabric heavily impregnated with latex layed up between two sheets of heavy glass to produce a nice flat and flexible air-proof sheet . My first attempt was a bit too flimsy, so I just choose some heavier cloth, cotton I think, and the latex used was Copydex which being a natural latex eventually disintegrated because of the diesel engine fuel, though an electric model would not cause this. Silicone or polyurethane rubber might be better .
Trevor