Can a stainless steel dehydrator be repurposed into a solar dehydrator?

I've got a 9-tray all-stainless-steel dehydrator that doesn't work very well. It heats vwry unvenly and the timer and temperature knob are very iffy.

I'm wondering if I took it and, say, painted the exterior with high-heat black paint and maybe drilled some ventillation holes (if it needs any) if there might be a way to repurpose it into a solar dehydrator. I could perhaps stick an analog thermometer in through a hole to help monitor the temps. Anyone done something like this?

It's the kind of thing that it's cheap Chinese landfill junk but might be put to good use. Would I stick it inside of a box with a glass lid or something like that? I know I'd need to screen it to keep insects away from the food. In Zone 8a here, we have pretty intense heat sometimes. I'm just wondering if it might work just to paint it black and stick it out there...

Yes, you absolutely can.
Give us some good pictures so we can see how it's made, and we can give you better advice about holes etc.

:D

I think you could do well by painting one side black, and putting glazing over that side. The other sides could be insulated.
On the black side, drilling a few holes at the top and a few more at the bottom you might be enough to create a thermal convection current.
This is basically the same idea I had for converting a file cabinet into a solar dehydrator,  but your starting point is much better.

Pearl Sutton wrote:Yes, you absolutely can.
Give us some good pictures so we can see how it's made, and we can give you better advice about holes etc.

:D

Okay, here are some photos. Essentially, the fan blows through the sides across the trays. It has rubber feet, a glass front door, and the rest of the body is stainless.

Awesome critter you have there! I'll be back after I get stuff done and see what has been said already.
That will convert nicely!

William Bronson wrote:
This is basically the same idea I had for converting a file cabinet into a solar dehydrator,  but your starting point is much better.

I was thinking I could maybe put this inside an old filing cabinet we have, but it wouldn't fit. Great minds think alike!

The biggest pain/time user, is often making the trays, and the trays look nice. About what size are they, and how big is the gap between them? There seems to be two types also.  

In the conversion, you may find that without a fan to actively move the air, you'll want to try filling half the trays first. That partly depends on your eco-system.

Somewhere here on permies there are photos of either a washer or dryer that was converted to a dehydrator. This should be even easier to convert, I expect!

The easy way to do this might be to make a variant on this (not as big or anything, just the way the glass is in front, the dehydrator above)


The vents on all sides would be fine then, I'd make it's back face the glass so you can open the door to get stuff out. All you'd need is a glassed box, doesn't have to be spiffy, and a way to make it vent into the bottom of the dehydrator. Holes drilled in the bottom and it sits on the top of the glass box output would easily be enough. Glass box has similar holes drilled in it's bottom to let air in, and in it's top to let air out.

Jay Angler wrote:The biggest pain/time user, is often making the trays, and the trays look nice. About what size are they, and how big is the gap between them? There seems to be two types also.

The trays are 12"x16" with about an inch between them. Half are like oven trays and the other half are a mesh.

As far as a fan is concerned, I was wondering if I could somehow press into service one of those woodstove-type fans that run off the heat of sitting on the stove. I can't visualize how I would rig it, though. Maybe I should just try, like you say, staggering the trays every other one and just sit it outside and see what happens and go from there.

Should I plan to put this inside a box that I could leave outside? Maybe something angled toward the sun that this could sit inside of?We do have a good bit of humidity here.

I was looking at this build, which helped me visualize the whole convection thing. I'm pretty dyslexic.

Pearl Sutton wrote:I'd make it's back face the glass so you can open the door to get stuff out. All you'd need is a glassed box, doesn't have to be spiffy, and a way to make it vent into the bottom of the dehydrator. Holes drilled in the bottom and it sits on the top of the glass box output would easily be enough. Glass box has similar holes drilled in it's bottom to let air in, and in it's top to let air out.

Ah! I can see it...and that's a great suggestion to have the back face the collector. I have some old windows and boards, so maybe I can cobble this thing together! Thanks!

Without proper ventilation and temperature control, it will become a solar oven, not a dehydrator. A dehydrator needs two conditions to work well; adequate air flow around the food, and a temperature between 110 and 120 F. It already has a glass door, so mounting a reflector to direct the light onto the door and painting the rest black will take care of that part.  It's designed for electric, so it most likely already has a fan, a temp sensor, and some sort of microcontroller to cycle the fan and heating elements. Depending on the power requirements, it may be possible to just disconnect the heating elements and reprogram the microcontroller, then run it and the fan from a small solar panel. If not (for instance, if it's an AC fan and/or proprietary electronics), the fan could be replaced with a 12 volt DC one, and controlled with an Arduino or Raspberry Pi Pico and either the existing temp sensor or a compatible replacement. It might even be possible to dispense with a fan completely, by adding a tall exhaust stack attached to the exit vents to create draft, and controlling the air flow (and therefore the temperature) with a baffle plate and servo. You might even be able to do that with a mechanical thermostat arrangement of some sort, if you want to eliminate electronics. Or a hand operated baffle and a thermometer, if you don't mind having to check on it frequently.

I would get a replacement fan and use the dehydrator as intended.

Here is the thread about the solar dehydrator from a washer that Jay mentioned:

https://permies.com/t/181458/Debbie-Awesome-Super-Simple-Cheap

I hope someone comes up with some great ideas to use that dehydrator.