I love camping trips. Nothing beats going off grid for a week at a time with nothing but nature. The problem I have, though, is that to camp for a week at a time, my friends and I need a couple of massive food barrels for all the food we require. How to most people combat this issue? By re-hydrating dehydrated food, effectively eliminating most of the size and weight of the food until you're ready to eat it.

Purchasing dehydrated food is expensive - around $12+ per "meal" (and when camping I often need 1.5 - 2 of these "meals" to fill up) - so I looked in to purchasing a dehydrator.

On Amazon, the cheapest one was over $70, and it was too small for the use-cases I was looking for. After all, $70 for something so simple? I knew I could do something for cheaper.

And I did! Using recycled materials, this Cardboard Dehydrator costed me about $2 (for glue and tape). Here's how I did it.

Step 1: Supplies & Tools

Here's what's needed to make this project:

Supplies:

Packing Tape (tuck tape is probably better, but I didn't have any lying around)
Hot Glue
Screen (I used a random screen I found laying around, but something like an old piece of screen from a window would be perfect)
Cardboard (of course)
Computer fan (or any other type of fan)
Heating mat and thermostat (optional)

Tools:

Exacto Knife/Box Cutter
Scissors
Pencil/Marker
Hot Glue Gun

And that's it! Very simple.

Step 2: Step 1: the Main Box

I started with the box I wanted to use as the main chamber for the dehydrator. I found a box that was 12"x12"x24", a size I felt to be perfect for my needs.

I removed all the tape and other garbage that was on the outside and selected the side I wanted to be the bottom.

I carefully and cleanly re-taped the box back together, doing my best to eliminate any creases in the tape. I added 2 layers of tape to each seam, and an extra piece of tape over each corner.

This part needs to be air-tight, as it is imperative that the easiest way for the air to get in to the box is through the top.

I then flipped the box around and taped all seams from the inside as well.

Step 3: Step 2: the Fan

The next step is to trace and cut a hole for the fan. I chose to put my fan on the bottom of the dehydrator, as heat rises and I want to pull any heat back down and through the food I'm dehydrating.

Being extra carful. I traced an outline of my computer fan on to the bottom of the box and cut it out with my Exacto Knife.

I taped all of the edges I had just cut with more packing tape, again ensuring an air-tight seal everywhere.

I fit the fan in to the hole and secured/sealed it with some hot glue. Make sure the fan is pointed so that it is sucking air from the box and blowing it out.

Step 4: Step 3: the Legs

With the fan on the bottom, the box can't just sit on the ground. So, I had to make sturdy legs with holes in them so that the air can flow out of the holes.

I cut 4 pieces of cardboard that were slightly shorter than the width of the box itself (because that is what I had lying around) and used another smaller piece to trace out the holes.

I cut out the traced holes with my exacto knife and glued the legs to the bottom of the dehydrator using my hot glue gun.

Tip: When cutting the holes out, put a piece of wood or cutting board underneath to protect whatever surface you're cutting on. Cutting flat is much better than cutting vertically, as it can result in bending of the material which compromises its strength.

Step 5: Step 4: the Shelves

To make the shelves, I cut two 12"x12" (length and width of box) pieces of cardboard from a separate box. I then measured 1 inch in from each side, and used a square to cut the pieces in to a frame of 1" thickness for each shelf.

Dehydrating heavy items? For extra sturdiness, cut two pieces per shelf and glue them together.

To mount the shelves, I glued small pieces of cardboard to the sides of the box walls for the shelves to sit on when slid in.

I then cut pieces of my screen to size and glued them on to the shelves. I used a piece of plastic screen I found lying around, but any screen-like material that will allow air to flow through while still providing enough sturdiness to hold whatever you will be dehydrating. Something like a screen for a window is perfect.

Step 6: Step 5: the Lid

Since air needs to flow in through the top of the box and down through whatever you are dehydrating, there needs to be a vent at the top. This is as simple as cutting a hole in the middle of the box. I kept the cardboard attached so that I could close the vent if I wanted, however cutting it out completely also works.

The top does not need to be air tight as long as the bottom and sides are, since the flow of air will be from the top down.

I simply use sticky tack to hold down the sides of the lid to keep it closed. Something like a paper clip would also work to hold it closed

Step 7: Step 6: the Heating Element (optional)

Most dehydrators have a heating element included in the system, although it is not entirely necessary for dehydrating certain foods. It will, however, speed up the dehydration process for most applications.

For my heating element, I used a VivoSun Heat Mat and Thermostat ($25 from Amazon) that I had lying around from gardening and taped it to the inside upper part of the box. This worked well because it was flexible and I could control the temperature with the thermostat.

As another option, something as simple as a lightbulb would work. Pretty much any type of resistive heater that will fit on or around the top shelf and doesn't block airflow.