02_cone_layout  [2 of 4] ExhibitPlus here for the vortex filter. This page has the calculations for the cone dimensions. After getting the dimensions, I made the radii by cutting a thin piece of cardboard and pinning it to the center of a piece of wrapping paper (the gold in the photo is the wrapping paper -- make sure to use the cheap stuff or you'll hear about it). I pushed a pencil through the cardboard at the correct distance from the pin and made the circles before cutting the pattern. It would have been a good idea to check fit in the barrel at this point (I meant to, really!). I taped one end of 24"x10' aluminum roofing/siding coil to cardboard to keep it from rolling up, then traced the pattern from the wrapping paper." title="02_cone_layout I am basically following the plans here for the vortex filter. This page has the calculations for the cone dimensions. After getting the dimensions, I made the radii by cutting a thin piece of cardboard and pinning it to the center of a piece of wrapping paper (the gold in the photo is the wrapping paper -- make sure to use the cheap stuff or you'll hear about it). I pushed a pencil through the cardboard at the correct distance from the pin and made the circles before cutting the pattern. It would have been a good idea to check fit in the barrel at this point (I meant to, really!). I taped one end of 24"x10' aluminum roofing/siding coil to cardboard to keep it from rolling up, then traced the pattern from the wrapping paper." style="margin-left: 22px; margin-right: 22px; margin-top: 22px; margin-bottom: 20px" usemap="#ee_multiarea" />