Creating solar dehydrator from old tabletop oven

Hi all

I have a broken tabletop oven (looks like a big microwave but was convection) and I'd like to repurpose it as a solar dehydrator.

I live in the east coast of Spain 🇪🇸 so we get a LOT of sun.

I was thinking of removing the door and replacing it with mesh (or glass?)  I wondered if it would work better putting it on its back with the opening at the top, but that might mean that lower layers don't get dehydrated.

Any suggestions for me please?

Many thanks!  Helen

Helen Siddall-Butchers wrote:Hi all I have a broken tabletop oven (looks like a big microwave but was convection) and I'd like to repurpose it as a solar dehydrator.
Any suggestions for me please?
Many thanks!  Helen

IF you can obtain some fine mesh stainless steel screening that might work for the opening. IF you can stack racks inside I would leave it upright, but on a bit of a tilt to allow water to drain out.

I'm going to try and go real low tech on a dehydrator this summer. I have two ceramic tiles, I think 12" X 18" which I will build a stand for with the same type of mesh over the top - OR - a thick plate glass cover. The tilt will be in the stand itself and drain to one end with a channel to eliminate the water.

Interesting project!

I find dehydrating works best when there is heat and airflow.

If the oven does not heat up but the little convection fan still blows, you may have a perfect solution that is quite energy efficient. The heating element uses most of the electricity.

If not, I would leave the door slightly open and plan to move the bottom rack to the top partway through the dehydration process.

If it is like what we call a toaster oven here..... I would put a slight tilt on it (do to your location) a hole on top towards the back that i could put a piece of pipe or a square tube painted black (made of metal) to act as a chimney to pull air our. the front can be simple metal painted black on the outside with a mesh for about 3cm (or an inch) or just use and 80 or 90 % solar screen across the entire front... rotating racks helps in most decorators. In simplest terms remember all you are trying to do is warm the air and move the air.... so there is a lot of ways to make it work.... On the forums here plus sites like build it solar can give you lots of ideas....  Give the dimensions  and see if some one can size it for you...

IF you can obtain some fine mesh stainless steel screening that might work for the opening. IF you can stack racks inside I would leave it upright, but on a bit of a tilt to allow water to drain out.

I'm going to try and go real low tech on a dehydrator this summer. I have two ceramic tiles, I think 12" X 18" which I will build a stand for with the same type of mesh over the top - OR - a thick plate glass cover. The tilt will be in the stand itself and drain to one end with a channel to eliminate the water.

Some good ideas here thanks Jesse!

As I've never had any form of dehydrator, I hadn't even considered where the moisture that's removed would go!  Definitely some sort of tilt then.

I have some old mosquito netting from a window replacement that might work for the front.

When it's light I'll investigate the setup at the back, and how easy it would be to make a ventilation hole.

Your low tech version might actually be just as effective and much easier to arrange! 🤔

Pat Hupp wrote:If it is like what we call a toaster oven here..... I would put a slight tilt on it (do to your location) a hole on top towards the back that i could put a piece of pipe or a square tube painted black (made of metal) to act as a chimney to pull air our. the front can be simple metal painted black on the outside with a mesh for about 3cm (or an inch) or just use and 80 or 90 % solar screen across the entire front... rotating racks helps in most decorators. In simplest terms remember all you are trying to do is warm the air and move the air.... so there is a lot of ways to make it work.... On the forums here plus sites like build it solar can give you lots of ideas....  Give the dimensions  and see if some one can size it for you...

Thanks for this Pat!  I love that simple 'warm the air, move the air' idea.  I'll adopt that as my mantra while I'm working on it!

I'm off to do some more research on the solar site you recommended, I'll update with my progress.

Douglas Alpenstock wrote:Interesting project!

I find dehydrating works best when there is heat and airflow.

If the oven does not heat up but the little convection fan still blows, you may have a perfect solution that is quite energy efficient. The heating element uses most of the electricity.

If not, I would leave the door slightly open and plan to move the bottom rack to the top partway through the dehydration process.

Thank you Douglas, I'm doing my best to reuse and repurpose where possible.

I will investigate the state of the fan; if that works that will save me having to make holes which might be tricky to do.  

I think replacing the door with a mozzie mesh screen will improve airflow too.

I'll report back on progress!

Pat Hupp wrote:If it is like what we call a toaster oven here..... I would put a slight tilt on it (do to your location) a hole on top towards the back that i could put a piece of pipe or a square tube painted black (made of metal) to act as a chimney to pull air our. the front can be simple metal painted black on the outside with a mesh for about 3cm (or an inch) or just use and 80 or 90 % solar screen across the entire front... rotating racks helps in most decorators. In simplest terms remember all you are trying to do is warm the air and move the air.... so there is a lot of ways to make it work.... On the forums here plus sites like build it solar can give you lots of ideas....  Give the dimensions  and see if some one can size it for you...

I was thinking along the same lines, with holes around the outside of the oven...covered with mesh so no "visitors" get in.  The pipe idea is brilliant!  I'd use that, like Pat said, to draw the air out to create air movement for more effective dehydration.