Prefilter screens for Blueair 7700 series Air Purifiers

Do you have a Blueair 7700 series air purifier such as the 7710i or 7740i? If so, you may have damaged or misplaced the two Prefilters that keep large particles and dust out of the machine. As these pre filters are no longer available and the 7700 series machine is too large, expensive and well-made to just discard, you can print out these handy Prefilters! You can also utilize your choice of pre-filter screen, either finer or coarser than the originals or use a different material. Unlike the original Prefilters, these are ambidextrous and fit either the Left or Right side. They are sized to fit a 7710i well with a 0.5mm thick screen sandwiched between two identical 1.5mm thick pieces for a total thickness of 3.4 - 3.6mm. Just obtain some fine-weave window screening, some epoxy cement and print out two pieces for each assembled filter. assembly: 1- place one Prefilter half down on a flat surface 2- apply expoy glue to the top of the first half. 3- place the screen on top of the first half. 4- place the second Prefilter half down on top of the screen, aligning it carefully with the bottom half 5- press down on the top half using a board, block or what have you to squeeze the epoxy though the screen, rechecking the alignment of the halves before the glue dries. 6- after the glue dries, trim the excess screen from the perimeter Enjoy!