DIY Sandwich Filter Net

Tools

• Scissors or knife
• Needle & strong thread (or zip ties)
• Measuring tape
• Ladder (if tall frame)

Safety

• Anchor the frame so wind cannot tip it
• Boil or filter stored water if unsure of quality
• Keep charcoal sealed dry until install

How to put it together

1. 1

   Cut the layers

   Cut shade cloth, mosquito net, two cotton sheets, and fine mesh each to about 2m × 2m. Keep edges square so layers stack cleanly.

2. 2

   Make the charcoal sandwich

   Spread activated charcoal evenly between the two cotton sheets. Stitch or zip-tie the cotton edges so charcoal cannot spill.

3. 3

   Stack the sandwich

   Order from outside→inside: shade cloth → mosquito net → charcoal cotton pack → fine mesh. Align corners and pin temporarily.

4. 4

   Build the frame

   Use 4 bamboo/PVC poles (~3m). Make a rectangle standing at ~15° tilt facing prevailing fog/wind. Cross-brace the back.

5. 5

   Stretch and fasten the panel

   Lash the layered panel onto the frame. Keep fabric taut but not tearing. Leave a slight overhang into the gutter line.

6. 6

   Add the gutter

   Cut PVC lengthwise as a gutter under the bottom edge. Slope it to one corner that drains into a clean 20L bucket with lid.

7. 7

   Test & maintain

   Spray with clean water from the top — drips should reach the bucket. Replace cotton/charcoal on the schedule in the materials list.

Tips

• Face the panel into morning fog or prevailing moist wind
• Raise the bottom edge so animals cannot drink from the gutter
• Add a second panel in parallel to roughly double yield