Solar Food Dehydrator

Build a wooden frame about 60 × 60 cm and 120 cm tall, elevated on legs off the ground. Fit six internal rail pairs so trays slide in and out.

Cut clear acrylic sheet for the four walls, top and bottom; peel the protective film and screw the panels to the frame. Use acrylic or tempered glass — never polycarbonate, which off-gasses BPA and VOCs near food when hot.

Build a framed, acrylic-glazed door for the front on two or three hinges, with a latch to hold it shut.

Drill a 25 mm vent hole in the top-centre before fixing the top panel. Cover every vent with fine insect screen.

Make six shallow wooden tray frames to slide on the rails. Staple food-grade stainless-steel mesh across each — not fibreglass window screen, which sheds fibre into food.

Optional modern upgrade: fit a small solar panel and one or two 12 V fans to push air up through the trays, angling the panel toward the sun. The dryer still works passively without it.

Load the trays, aim the box at the sun, and read the inside temperature with a thermometer. Aim for 50–70 °C (120–160 °F): cover the vents and switch fans off to run hotter, open vents and fans on to run cooler. Heat rises, so put wetter food on the top racks and drier food below.

Dry until leathery or crisp — herbs at about 35 °C for a few hours, most fruit and vegetables at 50–60 °C for 6–12 hours or more. Cool fully, then store in airtight jars away from light.