Building Our CR Boxes

Step 1: Inspect Materials (5 min)

• Check that fan works (teacher quick-tests)
• Verify all 4-5 filters are present and correct size (20"x20")
• Locate the airflow arrow on filter frames
• Inspect filters for damage

Step 2: Orient Filters (5 min)

Critical: Air must flow INTO the cube, through filters, then out through fan.

Position filters so arrows point INWARD (toward center of cube). "Dirty air enters from outside, passes through filter, becomes clean, exits through fan."

Step 3: Arrange in Cube Shape (5 min)

• Stand 4 filters on their edges in a square shape
• Each filter edge should touch its neighbor
• Leave the top open (where fan will sit)
• Check that no filter is backwards

Step 4: Tape the Corners (15 min)

1. Interior corners first: Tape vertical interior seams where filters meet
2. Exterior corners: Tape exterior vertical seams
3. Use long strips of duct tape and press firmly
4. Wrap tape slightly around edges for strength

Quality Check: No visible gaps, cube is stable and square, shake gently - should not wobble

Step 5: Add Cardboard Bottom (10 min)

• Measure inside dimensions of cube
• Cut cardboard slightly larger (teacher only cuts)
• Tape into place from inside and outside

Alternative: Leave bottom open; cube sits on floor and pulls air from all sides

Step 6: Mount the Fan (10 min)

• Fan sits on TOP of cube
• Fan blows UPWARD (exhausting clean air)
• Fan's back (intake side) faces DOWN into cube
• Tape fan to filter edges - create full seal around perimeter
• No air should leak around edges

Step 7: Final Seal Check (5 min)

Visual Inspection:

• All seams taped (inside and outside)
• No gaps between filters and fan
• Fan secure and won't fall off
• Cube is stable when sitting on floor

• ☐ All filters oriented correctly (arrows inward)
• ☐ All seams taped inside and outside
• ☐ No visible gaps
• ☐ Cube is stable and square
• ☐ Fan mounted securely
• ☐ Fan oriented correctly (blowing up/out)