Introduction: Dehydrator

About: I am an aircraft engineer and love to do projects from time to time

This project took me about 2 days to accomplish. It costs around $25 and it does a perfect job at dehydrating fruits and vegetables.

Dehydrating fruits and vegetables can be quick, such as 6 hours for certain fruits and about 2 to 3 days for others such as raisins. You need to maintain a constant temperature of 57 degrees Celsius and allow for good ventilation to remove humidity.

material needed:

a 50cmX40X30cm box

thermostat (purchased from AliExpress) works well

220VAC Fan or 110VAC depending where you live

SPDT relay (to allow the fan to operate when the lamps are out)

Hi-Speed tape

wire racks

Step 1: Making the Box

The box is made up of plywood or similar with the following dimensions:

50 cm height

40 cm width

30 cm length

(50cmX40cm) for the front door and 50cmX40cm back side

50cmX30cm for the sides (2 each)

30cmX40cm for the top and bottom (2 each)

thickness of the wood should be 1.5 to 2cm minimum

Drill a round hole of 10 cm diameter on the top to accommodate the extractor fan

Drill a 7cmX3cm hole to accommodate the thermostat

Step 2: Insulating the Box

the best way to insulate the box is using metallic tape. (called hi-speed tape)

insulate all sides, this will keep the heat inside a reduce heat loss

Step 3: Wiring

i got this thermostat from the internet it's cheap and works extremely well at regulating the temperature;

remember that you need 57 degrees Celsius for most vegetable/fruits dehydrating process

I achieved this temperature by installing 2 light bulbs on the bottom (one 100W and one 75W) connected in parallel

I also added a relay SPDT in series with a lamp so that the Fan will run when the bulbs turn off when the temperature is reached allowing moisture to escape

Step 4: Adding Racks

Make the racks out of screen to fit inside the dehydrator. I also found an old rack that fit perfectly

Step 5: Final Product

You can almost dry anything, tomatoes, bananas, apples, even onion and garlic, which take less time.


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    Question 3 years ago

    Hello! Why add an spdt relay? you can not connect the fan directly past the thermostat, so that it works all the time?


    Answer 3 years ago

    because I don't want the fan to work all the time; I only need it to work when the set temperature is reached, this will trigger the fan to start and will stay on until the lower temperature is reached (usually about 2 degrees difference) this will allow the moisture to escape in that short period of time (about 30 to 40 seconds); in the next upgrade, I will add a timer to start/stop the fan every 1 minute or so


    Reply 3 years ago

    Thanks, I didn't try yet but should be easy, should only increase the temperature to 160 degrees F or 71 deg C