Instructables

Box food dehydrator

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Picture of Box food dehydrator
Inspired by the Food Jammers, these are plans for a food dehydrator based on the one they used to dehydrate a turkey.  Mine will mostly be used for fruits and jerky but you can literally dehydrate anything with it and if you have access to a junkyard and thrift stores you can find a lot of the major supplies for cheap making the whole project less than $30. 
 
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Step 1: Tools and supplies

Picture of Tools and supplies
DSC_0059.JPG

Tools
Circular/ table saw - not really needed if you have a lumber yard that will cut to size for you
Power drill
Wire cutter

Supplies
Plywood- preferably 3/4 in thick. I used 1/2 in and it worked fine though
metal racks- For the shelves, I went to a local recycling center. They were nice enough to let me dig through their pile of appliances and random metal. There I found 5 racks out of old ovens and had them cut down so they were all similar sizes. they sold me all five for a $1 so I couldn't complain with that.
light sockets
wall plug in
wire- i used 12 guage, probably could use something smaller
cabinet hinges
some type of closing mechanism- I took a metal clamp off an old grill that works great to hold the door closed
small fan - You can usually fine these for cheap at any thrift store
light bulbs

optional
wire mesh- I live in an area where there are a lot of bugs, therefore I put mesh on the air holes to keep them out

Step 2: Cut wood panels

Picture of Cut wood panels
Figure our the size you want your dehydrator to be and cut the panels to size.  Mine ended up being 19" by 16" because that was the size that fit my shelves.  I left the height a 4' so I wouldn't have to cut down the plywood from it's original size.  The leftover wood I used to cut feet and holders for the shelves.
awire8 months ago
The steps you are telling is simple and humble to set compost screen stainless steel wire mesh. The racks should be chosen with the high quality to extend durability.
http://brand4india.com/wire-mesh-suppliers/products/stainless-steel-wire-mesh/
pdyson2 years ago
To use this unit correctly you need the following temps, Herbs= 105F, Fruit n veg =135F and Fish n Meat=150F to 155F.
12v fans easy found in old pcs and there power pack are easy to wire, put a few in to move the heat around even.
Bulbs are the best way to heat this unit cheap but remember its the heat you need heating the food not the light.
If your going to use mains power and you only want it for lets say fruit n veg you could fit a basic thermal switch that opens contacts at 135F this way you should get the perfect drying temp for them type of produce.
Its also a good idea to check the temp in each tray bay some movement of the fans will be need to get the heat just rite. A unit of the above size will need 4 one inch vent holes top and near the bottom if you make the vents on diffrent sides this will help promote air flow in your cabinet...One last point you should use pot light fittings as this units get rather hot around the bulbs and the fitting will burn and go brown, it may even give of some gases that may affect your food over time, good luck with your project and happy drying;-)

X86-11382 years ago
Love this project. It's a giant Easy Bake Oven.
My question is what happens when they stop making incandescent bulbs?
No more dried food :(
static X86-11382 years ago
They are NOT going to stop making incandescent light bulbs. They have already developed incandescent bulbs that meet the efficiency standards. Yes we will pay more for them like we already pay more for cars that meet fuel economy, emission, and safety standards.  Many dry food without using electrical power at all, with using dryers that have a screen enclosure that allows natural air circulation.
From what I read, they are eliminating them for the general public. Companies can still get them.

Get a FIN, and your set.
Instead of the light bulbs you could use Halogen Lamps they have a lower efficiency when it comes to heating but those are not banned yet.
bmwonderly (author) 2 years ago
I did watermelon but it turned out kinda weird. Some people I work with said that the melon tasted over ripe so that may have been the case. I lost some that fell through the grates. I have used my cooling racks that stack easily to dry bananas which turned out amazing. Gordrh, I didn't think about using a metal mesh for shelves. I do have some leftover metal mesh used for window screens. I haven't noticed the plywood affecting the taste but the watermelon had a strange smell that may have been from the plywood.
pembo2102 years ago
In a house plug, the black wire is the Hot wire. The White is a neutral/ground. Whites can be hooked from one item to another item's hot black putting them in series. The downside is that when in series, the things further down the line depend on the power to go through the first things. The best is to have the small prong (hot/black) hooked to all black hots(tip of the bulb), then have the large prong (white/neutral)hooked to all the white wires(outer edge of the bulb).

Black wire
   |
   |
/  |  \
OOO
BBB
OOO
\  |  /
   |
   |
White wire
yep this would be the way I would do it. this way when one light bulb died it would not effect the other bulbs only time of drying and heat
oops. i responded to step four, didnt know this was already covered.

THNX, good info XD
bmwonderly (author) 2 years ago
I'm going to have to try the hanging food with toothpicks idea. I've lost some of the watermelon I have in right now from it shrinking and falling off the racks. I've had someone else say the same about temp with jerky but the way I make it the brine I soak it in actually cooks it. I've dried it multiple times before with just a box fan and no heat but with no issues.
In the one I have built, I use stainless steel window screen on a wooden frame, this allows me to dry out just about anything, especially jalapeno peppers and herbs from the garden
I had a thought, what if you used Stainless steel cooling/baking racks. Just google them and you'll find some with a screen look. The holes are smaller, and you can lay them on top of the stove racks. Heres an example of what I'm talking about. http://www.surlatable.com/product/PRO-8771/Stainless-Steel-Baking-and-Cooling-Rack?affsrcid=Aff0002
The tooth picks work good for hanging meat. I wonder if the water melon would support its own weight hanging from a tooth pick though?

I had a link but can't find it now, for Stainless steel mesh to lay on the racks for smaller or delicate items. I know you don't want to use hardware cloth (galvanized metal screen) because of lead, zinc, ect contamination. Same problem with window screen weather metal or fabric. I have seen perforated tray for use in a barbecue grill that should work too.

Have you noticed any of the plywood odor in the food?

Gordy
I make jerky using the very large metal ka-bob skewers you get at walmart (camping gear - six for $5.00, if I remember - I bought a few sets). The cross-section is a half moon so it stays in place on a flat surface (the rack) and somewhat distributes the heat across a half-moon rather than a cusp, so you don't get a burned flavour added. It is easy to put large (thin) pieces of meat on the skewer which is at 90 degrees to the rack. An old cookie sheet covered with aluminum foil will catch drippings and can be tossed if you don't use the unit much (builds its own multi-coloured "not for me" if left too long). If you use it a lot you can build the drip pan, literally to taste. All that aside, once you have the cabinet and slow heat source as you do, these skewers work well because you have an axis and transverse axis to hang the meat on without overlap.
Nice photos.....Why would anyone buy lumber to make this when refrigerators are free? .. They come in all sizes and usally people have to pay to have them removed. ..... Two 100 watt lite bulbs in series will last about 20 years since they will run at 1/2 v. Heating elements all work o the same principel. Run in series gives 1/2 wattaage so you dont have to worry about hot spots or burning them out . Same with 220v elemonts like from a discarded comerical freezer I hav used thes for years on 120 as heating elements, the surface temp of the fins is low maybe 120 or 150F.. ....
A smoker unit can use a refer too. I find most any free junk rice cooker or ? ,,..thermo switch can be adjusted to 130 F to 250F . Auto zone sell a remote one for cars, for abot $17 with about a 5 or 10 degree diferential. Remot adjustable switch, and a 1/8" line about 2f long to a 1/4" sensor unit to sit inside. Will handle 15 amps easily. Works great for big fan.
With the light bulbs being on the base, doesn't that let the juices from the meat/fruit drip down on to them?

do you or can you cover the bulbs?
overblast2 years ago
I got a 15 sheet bakers rack at a restaurant auction for $15 b/c my wife cooks a lot for parties at Christmas. So I'm going to use that, great 'ible! All I should need is to build a shell of plywood.
magickaldan2 years ago
Hooking all you light in parallel would be the proper way to do this. It will distribute equal power to all your bulbs, right now your not getting full power if you have the wired up in series like It looks like you do. You really want your box temp to be around 140 to 160 for jerky.
L1 = one line of your power and L2 is the other one.

O = connection on light sockets.
B = Indicates Bulb

L1 L2
| |
O B O
| |
O B O
| |
O B O
I have to agree with putting the bulbs in parallel. All of the bulbs will get the full power of the electrical source and give you the most heat as opposed to sharing it if you put them in series.
this is what your trying to say
inst.jpeg
Loki-me2 years ago
I like the idea of the your dehydrator, but you should try adding some screened holes in the top and bottom of your box. Your design lacks an exit for the water you our trying to remove.

Without holes for air to circulate in and out of the box, warm moist air can't carry away water while making room for dry air to enter the box. The concept is that air moves into the box and heats up. Which lowers the airs relative humidity allowing the air to absorb water from the food. Then by fan or convection the moist air is removed from the box, taking away the moisture. Thus dehydrating or drying the food. Some commercially available dehydrators have no heat source at all only a fan for forced air dehydration.

If you establish an airflow through your dehydrator you will greatly increase the speed and efficiency of dehydration. You have to let the water out!

marcintosh2 years ago
People are concerned about the availability of lights for heating.  Relax, I've got it covered.  get thee to a pet store and look for these-

http://www.drsfostersmith.com/product/prod_display.cfm?c=6016+11148+19739&pcatid=19739

They're heaters for reptile cages.  Heat is heat either from a light bulb or a ceramic heater.  It's what I use in my pump house all winter long.  That's not an endorsement of that particular store.  It's just the first image I could find.

As an improvement. I'd like to suggest you paint the inside with Food Grade Shellac.  That will keep it easy to clean and prevent the out-gassing of the glues in the plywood from "seasoning" the food with toxics.  The shellac is inexpensive in the long run and really, nearly any version of shellac is food grade.
Thanks for the 'ible I'll make one this week!
M
rippa7002 years ago
You can get low power heaters used in things like egg incubators and plant propogators. Bulbs are just good and cheap.
rippa7002 years ago
This is a great idea - thanks. I've been meaning to do something like this for a while. I think you need to make sure that no juice drips onto a hot bulb or it will explode! A simple roof over the bulbs should do that. Looking forward to my dried fruit already!
gcruik2 years ago
Consider window screen as support material for what you want to dry. No fall through. Easy to make wooden frames, Window screen material comes in rolls.
this would be a good idea if you could get staleness steel screen. most of the screens are made from plastics under heated conditions there is risk of chemical transfers that could effect the foods, and the metal screens are made of low grade steels and many times Galvanised , witch is Zink and will effect the foods
mprout2 years ago
rig a space heater to it.
I recently made my own incubator using a 12v thermostat and some 12v car lamps. The lamps, 2 wired in parallel produced more than sufficient heat to get the temperature up in the incubator quickly.
I also encorporated a 12v computer fan to move the air around inside the incubator.
I re-puposed a deceased Xbox 360 psu to provide the power, although Solar and batteries would be an easy future option as the system is already 12v
Why am I telling you this? well perhaps you could use the same system here. get a 12v thermostat with a switchable output, when the temperature drops below a certain level it sitches the lamps and fans on, when if get to the right temperature it switches them off again.
Something like this http://www.ebay.co.uk/itm/Hot-New-12V-Digital-Temperature-Control-Controller-Thermostat-Aquarium-Gardening-/170698884528?pt=UK_AudioElectronicsVideo_Video_TelevisionSetTopBoxes&hash=item27be7245b0 might work for you. Although you may need higher temperature ranges for the smoker.
bmwonderly (author) 2 years ago
I have thought about using it as a smoker too. I would just have to switch out the light bulbs and fan for a hot plate. I think I meant to say that in the instructable but forgot. I have even thought about making it solar powered at some point. If I would use it as a smoker, I would use my probe thermometer to track the temperature. I would probably stick it through a wine cork and plug up one of the air holes with it so it stays in place. there's probably a better way to do it, I'm just thinking about what I have on hand.
Dr.Bill2 years ago
I like this dehydrator box because it leaves a lot or room for new ideas and changes.
There has to be a better way to heat the box without using house current.
Blainer2 years ago
Some nice thoughts there bmwonderly. I see the design and my first thought is "smoker"!

I wonder how you track temperature with that. Did you add a thermostat?
kill-a-watt2 years ago
stockpile yourself some 100 watt light-bulbs while they're cheap. Next year you will need to sub in 4, 75 watt "rough service" bulbs at about $5 each to get the same wattage.

The wiring looks OK, but it would be better if you stuck it inside some electrical boxes.

Keep us in the loop about using plywood too. I would be somewhat worried about fumes from the glue, but if it's working out good for you that would be great!

The used oven racks scrounged from the scrapyard are a fantastic idea! Wish I thought of that.

I've made jerky before in an electric oven and found I could hand a whole bunch of meat strips if I put a toothpick at one end and dangled the meat below the oven racks by the toothpick.

magickaldan2 years ago
That didn't come out right but you should get the idea