DIY polystyrene super-cooler

Function > Form

New member
Hey gang,

We built a double-thick polystyrene cooler a couple weeks ago based on a wild idea over a couple glasses of something or other. In fact, we used it in ~+30C weather for 3 nights, 4 days. A warm bottle of wine took a touch less than 15 minutes to cool down to *ice cold*.

Professional design attached ;)
IMAG1666[1].jpg

Our internal measurements are 18” high, 16” deep, 30” wide
*add 8 inches (4 inch walls on each side) for the external dimensions. YUP it's big, but it stays at a rural property.

STUFF YOU NEED:

a) 3 sheets of 4x8 Durofoam at ~$32 each (Home Depot). We used approximately 2.5 of them.
Note that these are actually 1-15/16" thick; verify dimensions of your product as you design/build.
b) Lots of aluminum tape for temporary/minor abrasions to the foam if you are not immediately building a cover
c) Recently sharpened non-serrated knife with a thin blade (at least 6 inches makes it a bit easier) – if you have a hot wire cutter or
similar, I’d suggest using that!!
d) 2 tubes of silicone (100%) and a caulking gun

A couple notes before you start your own design:
This does not take into account the prototype phase to ensure everything will fit inside (and that it will fit in your vehicle).

As polystyrene is not very strong on its own, ensure that you overlap the various joints to make it ‘stronger’ (see pic).

Measure your ‘cooling solution’. For us we thought it might work well with a frozen 5 gal/20L water container (e.g. Reliant or similar brand) – ours measures about 10.5” x 12” x 15.5” (spout in) 17” (spout out).
When you freeze it, keep in mind the following:
a. leave enough room for the water to expand; and,
b. The spout may be frozen in the ice for multiple days, even if it is super hot out.

That's it! Let's get started on the real stuff.

INSTRUCTIONS:

1. Liberally apply silicone between panels A,B,C,D and I only where the red and green squiggles are, remembering that you will have to press them together to bond them (i.e. don’t add tooooo much, but don’t be stingy either).

2. Once you are happy with the ‘shape’ of your initial box, use some sort of rope or ratchet strap to hold it together for about 20 minutes (depending on set time of the silicone)
-Remember that all side panels (A,B,C,D in this case) need to be flush at the top to allow the lid to sit on it to give a good ‘seal’.

3. Once it has set, release the strap, and add in E,F,G,H, and J. This time, not only will you put silicone on the edges, but also between the flat panels.

4. The inner portion of the lid will fit in the open portion of your new cooler. It is essential that it sits into the hole so that the outer portion of the lid fits flush with the sides (refer to step 2).

5. As this is polystyrene, it is flammable without protection. You will need to make an external cover for more permanent protection (wood, metal, etc).

More pics to come. :)
 

Function > Form

New member
IMAG1675.jpg
IMAG1677[1].jpg
pardon the mess

thanks for the vid! I might try this
No problem!

We went out this weekend for two nights, daytime temps were around 24-28*C. The reliant container was only 1/2 full of ice this time around, frozen in our chest freezer.

I put in a cheap dial thermometer and it registered between 7.5 and 8 *C, which is fine for us (no meat or dairy). We will likely do a full container of ice next time and will record the results.
 

Wilbah

Adventurer
I like the idea of a custom built cooler that fits tour exact space needs. Another way to do it might be to make a shell out of thin wood for the protection you want first and then install the foam. The wood will provide the structure you need for gluing set up time. Might want to have a drain of some sort to for washing out.

I like it thanks!
 

jeep-N-montero

Expedition Leader
I like the idea of a custom built cooler that fits tour exact space needs. Another way to do it might be to make a shell out of thin wood for the protection you want first and then install the foam. The wood will provide the structure you need for gluing set up time. Might want to have a drain of some sort to for washing out.

I like it thanks!

Lots of videos on youtube showing how to do this exact thing, just don't get distracted or you can easily waste an entire day watching them.
 

dman93

Adventurer
Interesting timing on this thread, as I've been thinking about making a low, and possibly wide, cooler to fit under a pickup bed platform. Since the surface area may be fairly large relative to the volume, does it make sense to put it in an insulated divider? In other words instead of a 10" x 18" x 36" volume, make it two 10x18x18 boxes with a single base, walls and lid. It wouldn't make the space less usable (minus about 350 cubic inches taken up by the divider itself, though I guess that could be 350 cubes less ice) but could improve the overall insulation. Thoughts?
 

jeep-N-montero

Expedition Leader
Interesting timing on this thread, as I've been thinking about making a low, and possibly wide, cooler to fit under a pickup bed platform. Since the surface area may be fairly large relative to the volume, does it make sense to put it in an insulated divider? In other words instead of a 10" x 18" x 36" volume, make it two 10x18x18 boxes with a single base, walls and lid. It wouldn't make the space less usable (minus about 350 cubic inches taken up by the divider itself, though I guess that could be 350 cubes less ice) but could improve the overall insulation. Thoughts?

The divider would allow you to use one side at a time and use less ice, as opposed to one large space that would require more ice for even a small amount of food. For example, if you are just going up overnight and only wanted to take a pack of burger and a few drinks, you can just use one side/half of the box. The more unused air space you have the more ice you need to keep things cold, as you are trying to cool the unused space.
 

dman93

Adventurer
The divider would allow you to use one side at a time and use less ice, as opposed to one large space that would require more ice for even a small amount of food. For example, if you are just going up overnight and only wanted to take a pack of burger and a few drinks, you can just use one side/half of the box. The more unused air space you have the more ice you need to keep things cold, as you are trying to cool the unused space.
Thanks, this is starting to sound like it could be useful ... meat and dairy chilled on one side (plus beer) and veggies and fruit insulated from summer heat on the other side. All in one meta-container.
 

rruff

Explorer

I like it! Great DIY spirit!

4" of XPS insulation is definitely enough. It's so good that I bet the great majority of your heat loss is coming from air leakage. And the aluminum tape is going to carry a fair amount as well (aluminum is a great heat conductor).

If you used a low conductivity shell material (I'd fiberglass it, but other things will work) and an doubled airtight seal you'd have a super efficient cooler.
 

Function > Form

New member
I like the idea of a custom built cooler that fits tour exact space needs. Another way to do it might be to make a shell out of thin wood for the protection you want first and then install the foam. The wood will provide the structure you need for gluing set up time. Might want to have a drain of some sort to for washing out.

I like it thanks!

Agree. That was the original idea to make the shell, but I didn't want to invest all that time/effort/beer money if it didn't do what I needed. :) Also, the drain is a good idea, but it is so incredibly light, you just turn it upside down and wipe it with a dish towel. Mind you, I'm not using loose ice.

Lots of videos on youtube showing how to do this exact thing, just don't get distracted or you can easily waste an entire day watching them.

Ha! Yes, we did end up finding some videos after we thought it up. Funny how we hoomins think of similar weird things!

Thanks, this is starting to sound like it could be useful ... meat and dairy chilled on one side (plus beer) and veggies and fruit insulated from summer heat on the other side. All in one meta-container.

Yeah! Great idea to split it side to side. As noted above, we needed more ice for the whole thing to be as cold as a plug-in fridge. Good luck if you go this route!

I like it! Great DIY spirit!

4" of XPS insulation is definitely enough. It's so good that I bet the great majority of your heat loss is coming from air leakage. And the aluminum tape is going to carry a fair amount as well (aluminum is a great heat conductor).

If you used a low conductivity shell material (I'd fiberglass it, but other things will work) and an doubled airtight seal you'd have a super efficient cooler.

Thanks! Yeah possibly the air and tape are causing some heat loss, but it's minimal. Good enough for us...for now. Once it is more permanently situated (cabin), I may modify it further or do something a bit different. Thinking of doing and up/down style ice chest with the ice at the top supported by some sort of shelf (would have to be attached to the outer shell without conducting the heat inwards) and a separate door and a lower compartment that would hold food. Haven't given any serious thought to that yet.

Will be testing out the cooler again this weekend, but the weather is not as warm.
 

The Artisan

Adventurer
Doing something similar for my camper but using a cheap 70qt cooler and building a 2" frp container and coating it with truckbed liner, just like my camper pod.
Kevin
 

pray4surf

Explorer
Good old American ingenuity :D

I used a really thick polystyrene cooler (prolly 2" walls/bottom/top) used by Omaha Steaks and wrapped the bottom and the top with 1/8" lauan plywood, reinforced the ply corners, sealed and painted - I now have an extra cooler at minimal cost. The only drawback I've found - somehow/somewhere water is being trapped between the foam and the ply box...

It's as good as any coleman ice chest - if not better at keeping ice solid.. It'll probably work really well with dry ice....

Omaha Steaks also uses faux ice bags - No, I didn't subscribe to a meat service ;-) just a bunch appeared one day at the industrial park I work in...

All in all it was a fun little project.
 

Function > Form

New member
Tested it again this weekend but DANG it was cold out on Friday night. Got down to 3*C here and it was warmer inside the cooler at 5*C with a full container of solid ice...we left the lid open on Saturday morning!

After that it was a solid 6*C all day even with day time temps getting up to around 25*C. This is so much better than our cheap Coleman cooler we've been using for the last 8 years!! Drinks are actually 'cold cold', rather than 'cooler cold'.
 

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