Introduction: Simple (Deluxe!) Sonotube Food Dehydrator

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About: former musician. I have made kites, music instruments, electronic doodads, pitching machines, stomp rockets, water rockets, windless windchimes, circuit bent toys, animatronics, clock escapements, CNC router, …

I have always wanted to make a REAL food dehydrator, but all the plans I have found always start out "make a box..." That lets me out! I don't have the patience to make a box, let alone the skills to make it square, then add racks (also square!!) so I came up with a super easy way to make a container that looks like the commercial dehydrators using stacking trays in a cylindrical shape. It took me less than an hour and cost about 20 dollars. I could have scavenged and cut that in half, as I am sure many of you readers can. Read on!

Step 1: Things You Will Need

This design is so easy to make, all you need is a cylindrical tube, sold as a concrete form at the hardware store for around 5 dollars. They come in different diameters, I chose 30 cm. You will need some mosquito net, a zip knife to make the racks, and a staple gun to fix the net to the tube sections. For the drying unit I used an old heater made for warming up the car interior. Don't really know what you would call that in the US, since I grew up in Texas, and the last thing we would ever invent is a way to warm up the car interior! But here in Sweden it is common to own 2 of the things... Mine has variable heat settings, from 500 W to 2000 W and is built for 100% duty cycle, or constant running without overheating. (I paid 5 dollars at a local auction) I fould a small electric space heater online for about 15 dollars that would work. Add an oven thermometer and we're in business.

Step 2: Handy Tip

Use a zip knife, or box cutting knife to cut the tube into sections. Before cutting, draw a line lenghtwise along the entire tube. This will make it easy to stack the baskets so they fit perfectly and won't leak warm air. I also marked each basket with THIS SIDE UP and numbered them to ease in assembly. The base section is about six inches (15 cm) tall, and each stacking section is 2 inches (5 cm).

Step 3: How to Use a Zip Knife

When cutting cardboard (thick or thin) with a zip knife or an exacto knife, it will cut like butter if you tilt the blade in relation to the object being cut. In other words, don't stick the blade straight in and push, tilt the entire knife and saw in short strokes. In thin cardboard you can cut fantastic curves and shapes like this, but the tube I used is about 3/8 inches thick, so it was a more difficult job. Still, I cut 5 slices off the tube in about 15 minutes. Draw a guideline around the tube to follow when you cut. (You don't really need detailed instructions for that, do you?) The baskets don't need to be exactly straight, since the knife doesn't make any kerf, they will stack without any gaps between them.

Step 4: Attatching Netting

Cut out mosquito netting to fit the baskets. Cut the net slightly larger than the baskets, so we can staple it onto the tube. Stretch the netting slightly and staple it all the way around the tube.

Step 5: In With the Good Air, Out With the Bad!

I added a top to my dehydrator that included a flange to attatch the ventilation hose off my electric clothes drier in the basement. That lets me send the air from the dehydrator out through the vent in the wall. You can do this or just leave a hole in the top for the air to circulate. Your room will be MUCH warmer that way, but it smells good!

Step 6: One Last Step

I made an opening in the base for the heater, (shown in this step) being careful not to cover the fan intake. And That's IT!

Step 7: Thar She Blows!

I filled up the baskets with pears sliced on my old fashioned apple corer-peeler-slicer http://www.applesource.com/peeler.html (love that thing) and gave her a go. My oven thermometer showed 50 C after about 5 minutes. I wanted a little bit warmer, so I plugged the space under the heater with some dense foam rubber and the temp rose to 65 C in no time at all, that's about 150 F. Three hours later I had dried fruit!

I still have half of the tube left! I think I can cut some holes in the side of the tube, insert wooden sticks through the holes and use it for drying jerky. Hang the meat on the sticks and let 'er rip. Maybe a drip pan or something to keep the heater clean? Enjoy!