GRIDFALLSurvival
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Fire & Heat · 2 hours · Basic

Build a Cardboard Solar Box Oven

Reach 250–300°F with two boxes, foil and glass—bake bread, cook rice and pasteurize water with zero fuel.

This is for educational purposes only. Not professional medical, electrical, or safety advice.

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Warning

Cooked food must reach safe temperatures. Use a thermometer, and don't leave meat in the 40–140°F danger zone for over 2 hours.

  1. 01

    Nest the boxes

    Set the small box inside the big one. Stuff crumpled newspaper in the gap on all sides and bottom for insulation.

  2. 02

    Line with foil

    Glue foil, shiny side out, to all inner walls of the small box. Put a black metal tray on the floor to absorb heat.

  3. 03

    Glaze the top

    Cover the opening with glass or a tightly taped clear oven bag to trap heat.

  4. 04

    Add a reflector lid

    Cut a flap from the big box's lid, cover with foil and prop it at an angle to bounce extra sun inside.

  5. 05

    Cook

    Use dark, thin pots with lids. Aim at the sun and re-aim every 30–60 minutes. Rice ≈ 2 hrs, bread ≈ 2–3 hrs, beans 4+ hrs.

  6. 06

    Pasteurize water

    Heat water to 149°F (65°C) for 6 minutes to kill most pathogens. A WAPI wax indicator confirms it.