Ice Box From Reused Packing Materials

I spent a while researching a quiet cheap mini fridge for my bedroom, and was disheartened to find they don't seem to exist. I also researched some cool boxes and was disappointed that even the expensive ones did not seem to be insulated very well.

Then I realised I could make an ice box from some old packaging materials instead.

Much cheaper and quieter than a mini fridge :)

Notes:

As long as you have access to a freezer it should be cheap to run, if not it will end up being expensive in the long run because you'll have to buy ice to refill it to keep it cold.

I didn't design this to be moved about much, it is meant to just sit on the floor in my room. If you're planning to move it about (e.g. in a car) I'd put the whole thing inside a really sturdy container (e.g. a plastic storage box).

You could use kitchen foil instead of a foil blanket, just be careful because it tears very easily.

This is more fragile than a cool box so it might not last as long, if you want to make your money go the furthest you are better off buying a cool box unless you already have the materials for this lying around.

1. Large cardboard box
2. Small cardboard box that fits inside the large one, with plenty of space round the sides, and at the top
3. Foil blanket - the kind you get for camping
4. 2-3 Plastic bags
5. Leftover packing materials - Packing materials saved from deliveries and parcels. I had bubble wrap and polystyrene, which insulate well. I also had some shredded cardboard boxes. Cardboard or old paper works in a pinch too. If you ever get hello fresh deliveries you can use the insulated envelope it comes in. Jiffy bags and padded envelopes would work great. Old blankets, towels, sleeping bags, duvets would all work too.
6. Small water tight containers from your recycling bin - milk jugs, water bottles etc. cuboid ones are best
7. 2 Toilet roll tubes
8. Smallish old towel
9. Scissors or craft knife
10. Tape (lots, a couple of rolls) - wide tape is best

If your boxes are flat packed first tape the bottom shut. Now check that the smaller box will fit inside the larger one with plenty of space at the sides. It also needs plenty of space at the top because we need to insulate the top and bottom too.

The big box needs to be big enough for a few inches of insulation on all sides of the small box, which needs to be big enough to fit you food and an ice block layer.

Now close and tape up the top of the boxes just like you did the bottom. (Close the short flaps first and then close the long flaps over the top to make a smooth face and tape it up.)

Then get your scissors (or knife) and cut one of the long sides of the top face of each box. Cut through the tape along the gap between the top and the box side. You should end up with boxes with two short flaps at the sides and one large flap that covers the whole top of the box.

The outside of your lid should have a strip of tape on already. Open the lid out and tape over the join on the other side of the lid for both boxes. Cut the tape so it sticks out about 2cm from the edge of the cardboard and fold the ends round.

Cut the short flaps off and keep them.

Line up the short flaps with the short edges of the lid, then tape them down around their edges. This is a little easier with the box on its back so the lid is flat on the ground.

For both boxes:

First, with the lid open, tape along the inside of the lid hinge to reinforce it.

Then run tape around the outside of the whole top edge of the box.

With your fingertips, roll the tape over the front edge of the box and stick it down firmly to the inside wall of the box. Now repeat this motion along the top edge of the box, working out from the centre.

In the corners use a flat edge (like the blunt outside edge of your scissor blade) to slide the tape right into the corner.

Then do the same thing for each short side of the opening.

This should get the tape pretty flush with the box, but it doesn't matter if it has a few wrinkles.

Get your small watertight containers and arrange them in as close to an even layer covering the whole bottom of the smaller box as you can. Cuboid containers are best because they fill the space more efficiently, but round ones will work too. Fill them three quarters full from the tap and put them in the freezer.

Now make another set the same way. This is so when one set has thawed you have another to replace them right away.

For this step you need a large flat surface and your foil blanket, as well as your tape and scissors.

Carefully unfold the foil blanket and lay it out as flat as you can.

For this step we are going to roll the bigger box across the foil blanket to measure where to cut. This is a little difficult because if you step on the foil it's easy to shuffle it around or tear it.

First place the box gently in the centre of the foil blanket with the lid on the left, then tip it over to the right. Slide the box to the right until the edge of the box is about 2 inches away from the edge of the blanket.

Now, making sure the corners don't slide, tip the box back onto its base. Then tip it again onto its back edge and lay the lid out flat on the foil.

Now cut the foil off about 2 inches from the edge of the lid. Follow one of the fold lines to make it easier, and go slowly and smoothly to avoid tearing the foil.

Fold over the 2 inch edge of the foil onto the lid and tape it down. Now tip the box over carefully onto its lid (the box will be upside down), and do it again over the edge of the lid so it is off the edge of the foil.

The next step is we're going to stick the foil down to the outside of the box. You can do this pretty easy with double sided tape so if you have that go ahead and use it! However you can also do it with regular tape. I forgot to take a photo of this next technique, sorry because it's a bit fiddly.

What you want to do is cut a piece of tape about 1.5 inches long and roll it into a tube, roughly 1cm in diameter, with the sticky side on the outside. Where the edges overlap it will stick to itself and hold its shape. Make a lot of these and stick them all over the cardboard in the outside of the lid.

This step is pretty much the measuring step in reverse. Be careful because the foil doesn't unstick easily.

Roll the box back onto the foil so the sticky tubes you made stick the foil to the lid. Then repeat the steps of covering the face of the box next to the foil in sticky tubes, and then tipping it over so the foil sticks to the box. Repeat this until you get back to where you started.

The foil should be stuck to the box now, but the sides will still be unstuck.

Fold the foil corners on the side opposite the lid neatly using a hospital fold like you would on a bedsheet. Then gently pull the foil taut, fold it over the edge of the box and tape it down a good way down on the inside wall. You might need to trim it a bit if it is longer than the inside wall, it will depend on the size of your box. Tape it down along the seam of the inner box corner as well as along the edge of the foil.

You also want to do hospital corners on the corners of the lid - cut the foil a few inches longer than the sides of the lid, do your hospital fold corners, and tape the edges down.

Trim and tape down the foil in the hinge corners of the box. This is quite tricky and I gave up on folding it nicely and just bodged it! Just make sure the big foil triangle is tucked inside or taped down somehow, and that the foil edge is pulled over the edge of the box and taped down as much as you can so it can't get easily dislodged or get water underneath it. If you can avoid having any gaps of bare cardboard on the outside of the box that is ideal.

Now get your old packing materials and use them to make layers of insulating materials in the sides and bottom of the large box.

Leave the insulation a few inches short of the top of the box.

The idea is to get as uniform a distribution as you can of tiny isolated air pockets. I recommend overlapping the insulation by a few inches at the corners, and taping the insulation in place as you go, so that you don't end up with a gap as the insulation shifts over time. If you want to make adjustments later you could hold off on the tape, I didn't bother though.

The weight of the ice and food will compress the insulation at the bottom over time, which will make it less effective. This is what the toilet roll tubes are for. Cut each one into thirds and tape them evenly spaced across the bottom of the small box. Then pack inside and around the tube pieces with bits of insulating materials.

Between this step and the next one I put a lot of bubble wrap in there, but I forgot to take a photo. Build up the insulation wall by packing it out with as few gaps as possible.

Note:

I looked up some science of insulation for this project.

Gases are naturally poor conductors of heat because the large spaces between molecules mean one molecule of gas is less likely to bump into another molecule to transfer heat to it. However, also due to the large spaces between molecules, the individual heated gas molecules can travel far quickly.

So essentially even if your average air molecule is unlikely to bump into other air molecules it is pretty likely to shoot across the room and bump into the wall and transfer heat directly to the wall. So you are looking to make air that can't do that, and your best bet is to make many enclosed pockets of air! As far as I can tell this is why your insulation having gaps or getting squished makes it work worse - it can no longer prevent convection currents.

Put the small box in (gently!) and check there's a bit of space above it for the lid insulation. I did this by resting my hand flat on top of the lid of the smaller box and checking that my knuckles were below the level of the sides of the big box.

If you can move the small box side to side you need to take it out and add more packing materials. If it looks squished or the sides are bulging inwards you need to take some packing materials out. You want a snug fit but without the small box being distorted.

Now put more insulation around the top edge. I did this by making a roll of insulating materials and squishing it in.Then, making sure not to tape it to the small box, tape it into place as thoroughly as you can. You want as few gaps as you can manage, whilst still being able to remove the small box.

In theory it is better to make a fully insulated lid that will sit flush inside the box, but I tried this and it was very difficult to do with the squishy materials I had. If you have something solid for the lid insulation then I recommend skipping the roll in this step and using an evenly padded lid instead.

Tape a layer of packing materials to the lid, then build up a thicker layer in the middle of the lid directly above where the small box sits when the whole thing is closed.

I had a big piece of bubble wrap to tape over the top to hold it all in place, but how you do this really depends what materials you have. If it's all bits and pieces I would try taping over it all in a big sheet of tape, or even cutting open a plastic bag and using it to hold it all down like I did with my bubble wrap. The goal is no weak spots where heat can escape.

When I closed the box I saw it had a gap around the lid so I cut it a fringe of about 3 inches and taped it round the edge of the lid. If your box is similar I recommend doing this!

I used a black bin bag to line the inside of the small box. You really don't want water getting into the insulation because it will make your box mouldy so this step is really important. Make sure the bag you use for this has no holes in.

To do this step first check your ice blocks have frozen!

Put an open plastic shopping bag inside the small box, a strong one is good.

Line it with an old towel, a cm thick or so, fold it up if you need to get the right thickness. Then lay your ice blocks inside and wrap the towel around them. Then fold the shopping bag around the towel parcel and tuck the end under.

The point of wrapping the ice up is partly to absorb any leaks and partly to insulate it so it keeps your food cold for longer and also doesn't freeze it solid.

Now pack your food in on top of the cold blocks. To start with you should only put vegetables in there because you don't know yet how cold it will keep your food or for how long. It might not get cold enough to keep meat safely.

Pack your food in to fill as much of the space in there as you can, that way when you open the box the space inside will not get filled immediately with warm air.

I would recommend putting your food inside another grocery bag - it will make it easier to change the ice and is also probably safer for you long term than using bin liners. I just forgot this step when I took my photos.

To close the lid fully I had to put a weight on top. You want the lid to have no gaps round the side for air to get it, so weight it down if you need to. You could tie it down instead if you like.

Now you need to see how long it keeps your food cold for, to do this check every few hours by opening it up and seeing how cold it is in there. Use a thermometer if you have one, just put it on top of your food, just under the lid of the smaller box.

If you don't have a thermometer you can check the temperature by putting your hand in and seeing how cold it feels. When it stops feeling as cold as a fridge would normally you should swap out the ice blocks for the other set you made earlier, and put the thawed ones back in the freezer.

My ice box keeps things cold for about 24 hours. If yours lasts less time you might need another set of ice blocks so you can be sure to use fully frozen ones each time.

If yours doesn't keep stuff cold for very long you might want to open it up and add more insulation or a different type of insulation. Also make sure it is not next to a heater or a slow cooker, a PC, or anything warm like that!

You should wash the towel wrapping the ice blocks if it ever starts to smell or if it gets damp. You should also replace the plastic bags if any of them get holes in. If any of the plastic bags or the ice blocks get smelly you should clean and dry them thoroughly before replacing them. Lastly you should try not to put anything with surface water into the ice box, like freshly washed veggies.

If you have problems with condensation in there I would recommend a few sheets of kitchen paper or toilet roll (fresh from the packet - not one that's been in the bathroom) because they are very absorbent and not strongly scented.

If water leaks in there you should take the inner box out immediately and put the whole shell of the larger box with its insulation in an elevated place near a heater in a relatively dry room. You might need to replace the small box if it is too damp. I am not certain this will prevent mould but it might give you a fighting chance.

If the cardboard or the insulation gets mouldy you will sadly need to throw it away, I don't think that can be rescued.

I think with care it should last about a year, hopefully longer.

At the end of its life as an ice box a lot of parts of it should be recyclable or reusable, but sadly not the tape.

This is my first instructables so if you like it and you want to tell me please do, it would mean a lot to me :)