Rd40 particle filter

thingiverse

This is a DIY particle filter designed for standard 40 mm thread, compatible with numerous half and full-face masks. WARNING: * Use only when no certified commercial product is available due to situations like supply shortages during a crisis, and you are extremely desperate. * Never use the filter if there are cracks, layer separation, or any other defects present in the print. * Drop each part from 2m/6ft height onto a hard surface: if it breaks or cracks, don't use it! * Use the filter until breathing becomes more difficult, but do not use it longer than one day. * If using it as protection from substances like sawdust, you can carefully extract the filter material without releasing any dust, throw it away, wash and dry the filter, and refill with new filter material. However, if using it as protection from biohazards and very toxic substances, treat the whole filter as hazardous and dispose of accordingly. Instructions: * Print casing, inner grid, outer grid, and stencil using ABS for stability. * Drop each part from 2m/6ft height onto a hard surface: if it breaks or cracks, don't use it! * Push the inner filter grid into the casing with the circular protuberance of the grid facing towards the threaded side of the filter (according to schematic). * Use the stencil to draw 114mm/4.49" diameter circles onto microfiber dust wipes or microfiber vacuum cleaner bags, cut out at least six microfiber circles, stack them, and place the stack into the filter according to schematic (there should be no gap between casing and microfiber circles!). * Tightly push the outer filter grid into the casing with the little knobs facing inside the filter (see schematic). * Test if you can easily breathe through the filter: if not, don't use it!