Here’s a simple gadget that I built in a couple of hours a few years ago that makes a huge difference to the effectiveness of our freezer, by circulating the air so the stuff at the top and farthest from the plates does not thaw, while the food at the bottom and against the plates remains frozen, particularly when the freezer is packed tight.
The materials added up to less than $30 and over the years it has saved a lot of expensive food from spoiling; not to speak of protecting us from possible food poisoning as a result of partially thawed food—I get enough technicolour yawns from seasickness, thank you.
Here’s what you need to build one for yourself:
- A 12 volt computer fan, something like this will do
- A length of about 1-1/2 inch (4 cm) ID PVC pipe—ideal size is such that the ID matches the diameter of the fan blades, or a little bigger
- Some scraps of thin plywood
- Thickening agent for the epoxy
- Build a small box with a bottom, but no top, sized so the inside will just allow the fan to drop flat into it so that it rests on the bottom. Make sure the bottom is sized to fit inside the sides.
- Make another piece of ply the same size as the bottom. We will call this the fan mount.
- Said box should be about 3 inches (8 cm) deeper than the fan is thick.
- Before gluing the box together with the epoxy, cut holes in the middle of the bottom and the fan mount the same diameter as the OD of the pipe. Now’s the time to buy that hole saw set you have been lusting after.
- Glue the box together with the fan mount at a depth so the fan can rest on it with the top just flush with the top of the box. Some clamps will come in handy here. Wear gloves too, epoxy is nasty stuff—of course that won’t stop you getting it in your hair, as I always do…just call me resin head.
- Glue the bottom flush with the bottom of the box.
- Cut the pipe to length so that with the box attached to the top it will reach from the bottom of the freezer to the top as shown in the first photo.
- Cut the bottom of the pipe at an angle, as shown in the photo.
- Let the glued box set.
- Mix a thickened batch of epoxy about the consistency of peanut-butter.
- Insert the tube into the box so that the top is just flush with the top surface of the fan mount.
- Secure the box to the top of the pipe with a bead of thickened epoxy between it and the underside of the bottom of the box.
- If your carpentry is as dodgy as mine, after the pipe and box join sets, turn it back over and fill any gaps between the outside of the pipe and fan mount with thickened epoxy, so it does not leak air.
- Paint the whole thing with gloss enamel to make it easy to clean.
- Install gadget in your fridge with a couple of cable ties through mounts.
- Drill a small hole to run the wires out and, after threading the wires, use some spray foam to seal the hole around the wires.
If all of this is confusing the hell out of you, this close-up photo of the box at the top of the pipe with the fan just visible will help.
The Cunning Part
OK, about this time the battery misers among you are bitching about the electricity used by this fan running all the time. Not to worry:
The gadget on the right is a cheap timer available from Amazon. How do they build this stuff for so little, I ask you? Come to think of it, I don’t want to know.
Anyway, hook up the fan to the timer and you can program it to your heart’s content. We find that running the fan for one hour every four hours seems to be optimal.
There you go, just call me MacGyver.
Oh yea, one more thing. We found it works best if the fan sucks cold air up from the bottom rather than blowing warm air down.
If you just drop the fan into the box and don’t fasten it down—you made the box a nice snug fit, being the craftsman you are…right?—you can try it both ways for yourself, simply by flipping it over.
Also, not fastening the fan down makes it easier to replace when it dies. We find they last a couple of years, so best get a spare when you order the first one.