10' x 35' 45mil EPDM Pond Liner

Great

Works great just what I wanted, much thicker than before

10'x35' pond liner

Well, I received it ok, but the liner measured 11.5 'x 40'. So, I will have to cut the excess off which I am not too happy about because I have to think about how am I going cut it and with what?? Any suggestions: Box Cutter; Heavy Scissors?? What to place under for a straight cut?? Thanks, Gene..........