This model is my take on the DIY PET water filter based on this simple diagram.  

The filter is meant either for outdoor survival occasions, for areas without access to clean water or areas struck with some disasters where the infrastructure is damaged.

There is a variety of modules to choose from to allow everyone to craft a filter that suits them the best.

1. Filter_module
   - the core of the system, you will need at least 3 
   - do split into parts in the slicer and set “infill” and “layers and perimeters” on the cylinder by right clicking, in “layers and perimeters” set everything to 0, in “infill” choose a infill that you want to use for the mesh of the filter (i recommend gyroid), stay between 10-30%
2. Bottle_thread_top_module
   - allows you to screw a PET bottle with the standard PCO28 1881 thread
   - do split into parts in the slicer and set “infill” and “layers and perimeters” on the cylinder by right clicking, in “layers and perimeters” set everything to 0, in “infill” choose a infill that you want to use for the mesh of the filter (i recommend gyroid), stay between 10-20%
3. Funnel_top_module
   - another option to pour water into the system
   - do split into parts in the slicer and set “infill” and “layers and perimeters” on the cylinder by right clicking, in “layers and perimeters” set everything to 0, in “infill” choose a infill that you want to use for the mesh of the filter (i recommend gyroid), stay between 10-20%
4. Bottle_thread_module
   - module for screwing a bottle in the bottom
   - print as is
5. Glass_pouring_module
   - module to filter into a glass/container
6. Bottle_funnel_module
   - allows you to have a funnel on the bottom made from a PET bottle top
   - pierce two holes according to the pins in the bottle top and then secure it in place using them
7. Wall_hang_module 
   - use to hang the filtration device on the wall using two nails
8. End_bottom_module & End_top_module
   - close your filter for transport

Or just use the .3mf file in the files attached and hide the parts you don't currently print.

After printing, fill your filter modules with the needed substances, I used the following combination: Rocks, Sand, Charcoal and Cloth, but you can find variations using stuff like grass or rice, feel free to experiment. Also don't forget to put some sort of fine cloth or filtration paper in each segment so that the fine sand and coal don't flow away. I recommend filling only half of each module, or less in the charcoals case, as it is not easy for the water to pass through it.

Main advantage to using this over the basic bottle design is that you can separate each segment and change each individual part of the filter. The coal which is the most active part should be changed more often and the cloth as well.

!!! For your own health, make sure to either boil the water or leave it in the sun for 24 hrs to kill viruses !!!

Here's how to make charcoal:

How to Make Charcoal (with Pictures) - wikiHow

RECOMMENDATION for Prusa mk3

• Material: PETG
• Temperature: nozzle/bed 235/85
• Raft: no; Support: no (may be used for some places for less stringing)
• Infill: 10% grid
• Layer height: 0.20 - 0.30 mm
• Perimeters: 3
• Top and bottom layers: 3 is enough

Design: Filip Müller

[https://www.fa.cvut.cz/cs/galerie/portfolio/45621-filip-muller/atelierove-prace](https://www.fa.cvut.cz/cs/galerie/portfolio/45621-filip-muller/atelierove-prace)