Introduction: Solar Dryer Box

About: With a Master in robot engineering i'm very interested in open source technology and the developpment of simple and local energy sources. Besides that I'm a nature lover, wilderness guide and vision quest tuto…

Solar dryers are a simple and energy-saving way to dry your own food, herbs, veggies and fruits alike.

The solar dryer box is compact, easy to handle and can be disassembled in a few steps.

The basic idea for this dryer comes from the book "Sun Works Solar Food Dryer" by Eben Foder, which contains detailed information on solar food drying and instructions for a similar solar dryer box. The measures indicated in this instructable can be changed as you wish. They are a result to the glass panel i had available.

Step 1: Materials

I mostly used what recycled materials I had available. The words in brackets indicate the German names used in the drawings.

  • roof batten (ca. 25x50mm) for the legs (Beine), 2.74m in total
  • 20x20mm batten (Querlatten, Längslatten), 5m in total
  • 5mm plywood, 55x115cm in total (Sperrholz) for the front and back
  • 10mm plywood for the sides (Seitenwand), 66x53cm in total
  • Glass, polycarbone [attention, large dilatation] or plexi pane (Scheibe) 2-4mm thick, 63x53mm
  • Sheet Metal (Blech), 0.5-1mm thick, ca. 49x48cm
  • 8 20mm wood screws
  • 4 small hinges, ca. 30mm and screws
  • For the grid trays (Gitterrahmen): 12 metal angle brackets (10x50mm), 60 10mm sheet metal screws, 10x10mm square aluminium tube, 5.5m in total, fly screen, universal glue
  • water-resistant wood glue

Step 2: Fabrication of the Parts

Because it's fun and to allow for the simple disassembly, i used swallowtail halving for the connections of the bars. These should be manufactured very precisely. These connections can be fabricated differently if this seems to daunting, e.g. with metal angle brackets.

In the PDF-file you'll find all the measures to build the different parts. Attention, some of the battens (querlatten, längslatten) and the sides which need to be fabricated mirrored (gespiegelt) have different variations (varianten).

To manufacture the groove in the plywood sides you need a router. Alternatively you can also take 5mm playwood and fix little battens on it instead of the grooves.

Step 3: Subassemblies


One slanted 550mm batten and one with swallowtail grooves (Querlatten) are fitted into the cut-outs in the shorter legs (Beine) and glued (check for correct orientation of the swallowtail cut-outs!). Then fix the front plywood (188mm) with nails. Make sure the legs are parallel and the inner distance is 500mm minimally.

Sides: Staple pieces of fly screen onto the holes.


Take one slanted, two normal and two battens with swallwtail grooves (550mm) and glue them into the cut-outs in the longer legs (Beine). Check for correct orientation of the swallowtail cut-outs and make sure the legs are parallel and the inner distance 500mm minimally.

Now fix the lower plywood part (115mm) with nails. Then fix the two doors (260mm & 58mm) with the hinges. The upper door is for regulation of the ventilation. To be able to adjust the position you have to work the hinge with hammer or pliers to make it block slightly.

The latch for the large door could be made by a little wooden piece fixed with a nail, or you find a more clever solution.


Glue the shorter batten (490mm) inbetween the two longitudinal battens (Längslatten, 570mm) and then fit the whole thing inbetween the front and back subassemblies. (see images). If it fits properly, nail the floor plywood onto the battens in the correct place and then take the front and back away again.

The gap here is going to be the lower ventilation opening and should be covered by a piece of fly screen. To fix it more properly, you can add another 10x10mm batten as you can see in the images.

Sheet metal (Blech)

Bend one edge slightly upward as shown in the drawing and make 3 or 4 holes to fix it with screws.

Grid trays (Gitterrahmen)

Arrange the tubes correctly, place the angles on the edges, mark the holes and then pre-drill them (small). Cut the fly screen, place it underneath the angles and tighten the screws. Add another screw with a washer in the middle of each side to better fix the fly screen and if you want glue the screen onto the aluminium bars additionally.

Before you assemble the box, you should now treaten all the outside wooden parts with some fitting wood preservation. I used boiled linseed oil.

Step 4: Final Assembly

Now the subassemblies can be assembled in a few simple steps and be disassembled just as easily.

Fit the floor between the front and back with the swallowtails, mount the two sides correctly and fix them with a four screws to the legs. Then slide in the black sheet metal on the lowest groove and fix it with screws. The window pane can either be fixed with little wooden washers or metal brackets as you see in the image.

Have fun drying your own herbs, fruits and veggies :-)