First off, I want to give my humble thanks to FIGJAM. This swamp cooler was a blast to build, really ignited the “maker” spirit in me, and has bought me countless hours of beauty/recovery sleep at an event I go to yearly which takes place in an arid desert region - and for all that I am super grateful. However, I felt like instructions on building his, and similar swamp coolers were lacking the necessary detail for beginner builders to be able to successfully make one without assistance from a garage guru/handy person.
I’ve tried to make these instructions as accessible as possible, but you will need to be somewhat comfortable using power tools, and doing basic wire soldering (or befriending/bribing someone who knows how to solder) in order to complete this build. I’ve included links to places where you can purchase some of the more specific parts and tools, and you should be able to find the rest at your friendly neighborhood hardware store.
I've also incorporated a lot of "lessons learned" into this guide, so your cooler will (hopefully) look a lot prettier than the example in my pictures, which I built 3 years ago (and it still works great.)
Questions or comments regarding measurements, part names, QA, or suggestions on how this guide could be improved for others are welcome.
Step 1: Parts and Tools
- Phillips Screwdriver
- Power Drill
- Soldering Iron
- Heat Gun/Practical Method of Heating Heat Shrink
- Adjustable Hole Saw
- 1/2" Bit
- 2" Hole Saw Bit (or use the adjustable bit)
- 5/32 Drill Bit
- 1/8" Drill Bit
- Scissors, One Burly Pair Of.
- Wire Stripper/Cutter (use a wire cutter that can cut heavy duty wire, or have a bolt cutter handy - you’ll need it to cut the aluminum wire in the ducting)
- 36” or longer piece of twine/string/other way to measure round objects
- Tape Measure
- Caliper (optional, but strongly recommended)
- 5 Gallon Bucket and Lid
- ~3’ of 22AWG Red Wire
- ~3' of 22AWG Black Wire
- Heat Shrink (try to get an assortment/”variety” pack)
- 4’ of 5/16” ID Plastic Tubing
- 5/16" ID Plastic T Fitting
- 28"x34" Swamp Cooler Pad
- 4 2" #6 Phillips head bolts & nuts (preferably stainless/rust-proof) <- for the fan
- 2 1" #6 Phillips head bolts & nuts (preferably stainless/rust-proof) <- for mounting the exhaust port
- 2 1" #6 Phillips head bolts & nuts (preferably vinyl/plastic) <- for fastening the duct reducer to the brace
- 1" Zinc-Coated Steel or Plastic Corner Brace
- 5” to 4” Duct Reducer (Plastic)
- 3+ feet of 4” Ducting
- Front Mount Panel Mount Female DC Connector
- 12V 60W DC Power Supply (If you'll be powering this unit via a gas-powered generator or off the shelf [e.g. Goal Zero] solar battery/charger. If you'll be using a DIY Solar solution/other, see the step "A word on Power")
- 12V DC Water Pump
- Delta AFB1212SHE Fan
Optional (but highly recommended) Accessory:
Endless Breeze 12V DC Fan (to place in your tent, to push the moistened, swampy air through your tent and make it even cooler.)
You could save 15% by following this Note: Some of the parts used to build these swamp coolers usually come in bulk, or in a greater quantity than you’ll need for just one unit (particular the duct tube, and the swamp cooler padding). This is definitely a good group project to get a few people to help split costs and not have extra material left over.
Ok, now let's get on with the actual "making stuff."
Step 2: Crafting the Exhaust Port Thing
The first order of business is to mark the spots on the duct reducer to which we’ll be mounting the corner braces that will help secure this contraption to the bucket lid.
Measure the circumference of your duct reducer around the base (I.e. the 5” wide end.) and divide that in half to determine the locations for the mounting holes on each side.
Place the duct reducer on a flat surface, base down, and then place one of your corner braces up against the side of the base. Mark the spot where the vertical hole in the brace overlaps the side of the duct reducer. It should be about 1/2" up from the bottom of the base. This is where your first hole will go.
Make a corresponding mark for the second brace halfway around the reducer from the first mark. The two holes should be directly across from each other.
Drill holes through the marks you just made using your 5/32" drill bit.
Insert 1" #6 bolts through the sides of the duct reducer and tighten the corner braces onto to the duct reducer. Don't worry about the downward bolts for the moment, as we're first going to need those holes empty for the moment in order to verify the hole placement on the lid in our next step.
Step 3: Bucket and Lid Prep
¡ATTENCION! : Before you drill any holes in the lid, measure the diameter of the DC panel connector you purchased. I have one with a diameter of 1/2", so that's what I'm using as a reference in my diagram, but yours might be a different size. It's probably also worth checking the measurements for the corner braces/duct reducer holes to make sure they're correct for your particular corner braces.
FYI: The lid diagram/template image can be downloaded here, but make sure you measure it out/verify it if you plan to print it and use as as a reference. The template/example for the vent holes can be downloaded here
Hole Sizes/Bit used:
- Exhaust Hole: 122mm/4.8in
- DC Connector Hole: 1/2"
- Fan and Brace mounting holes: 1/32"
- Bucket Ventilation Holes: 2" Hole Bit
We’ll start with the lid. You'll probably want to cut the the exhaust/center hole first, as that's the basis for the location of your fan, and that way you can center everything nicely.
A word of safety on the adjustable hole saw AKA “The Twin Blades of Lid Evisceration” for those who haven't used one before: it feels a little wonkier while cutting than a single piece hole saw bit, so make sure to use your extra good caution. Ensure the lid is secured tightly and let the blades do the work - don’t push down forcefully while you’re drilling with it (i.e. BE SAFE.) Nuff said.
As far as setting up the width on the hole saw - if you've downloaded and printed the PDF template and it came out to scale, you can use that as a reference to go off. Otherwise, your best bet/easiest bet would be a good caliper that does millimeters and inches. If you end up making the center hole *slightly* bigger than recommended, it's not a huge deal - but make sure you stay under 5" so that the exhaust port/duct reducer will completely cover the hole.
Once you've made the hole, it's a good time to check it against your fan before we move on. Center your fan under the hole, and make sure that the lid isn't covering any of the fan blade area, but that it's also just wide enough not to have much of a gap between the fan chassis and the edge of the hole.
After the exhaust hole is looking good, you can place the template on the lid and use it as a reference for your mounting holes. Cut out the area where the center hole/exhaust hole is on the diagram, and line that up with the actual hole on the bucket lid. Securely tape the corners of the reference to the bucket lid using masking or packing tape so that it doesn't come off when you start drilling.
Before you drill the holes for the corner braces/duct reducer mounts, you might want to check to make sure that the actual holes on the corner braces match up with the template. If they look good, go ahead and drill them holes.
After you've drilled the corner brace holes, drill one of the mounting holes for the fan, and then use that to make sure that you can run a bolt completely through the lid hole and the fan chassis/mounting hole.
You might need to bore out the chassis holes on the fan if they're not wide enough.
If the fan's chassis holes are all good, drill one of the adjacent fan mounting holes, then run bolts through the lid and fan chassis for both fan holes you've made so far.
Make sure your fan is all centered up with the exhaust hole. If that's all good to go, drill the remaining two holes and then move on to the hole for the DC connector.
Once your lid is all set, just make sure everything is disconnected from it for now.
Next, we’ll drill the ventilation holes in the bucket.
I usually go with 2” holes with .25" padding on either side of each hole, but you may need to make smaller holes based on the size of your bucket or your personal taste.
So, here we go:
- Measure 1.75" below the bottom of the rim (the raised part near the top of the bucket that the handle is bolted into.)
- Mark that point with your sharpie. This is the center point of the first row.
- Measure the circumference of your bucket using your twine/string/measuring tape. (On my bucket, this came out to ~35")
- If the circumference of your bucket is ~35" at the point we marked, you're in luck - we can just divide that by 2.5 and get a nice clean number - 14. If not, refer to the note some people need to do for row #2/subsequent rows.
- Mark a 2.25" interval somewhere on your twine, or use measuring tape and carefully mark your 14 spots around the bucket.
- Once you’re finished, make sure that all of the points are the appropriate distance from each other and level, as these will be the reference for the next row of holes.
- Mark a point directly between two of the marks you just made for the first row, 3.75” below the bottom of the rim. This will be the first point of the second row.
- If you're using an HD bucket, the width/circumference of the bucket should about the same all the way down.
- If so, make another set of 14 marks. Sad Note: If you're not using an HD bucket (or identical type) or your bucket is angled/funky, you might have to make a google math detour at this point and research "how do I find the largest number I can divide into another number." in order to find the amount of holes per row.
You could do a third row of holes, but make sure that you leave at least a 3.5-4” gap between the bottom of your ventilation holes and the bottom of the bucket for water, otherwise you might have to refill your swamp cooler a lot more often than you’d like.
Once all of your future ventilation hole spots are marked, go ahead and 2" hole saw away.
Step 4: Preparing the Cooling Pad, Tubing and Ducting
Let’s start by cutting the cooling pad to size. If you're using an orange HD bucket, then go ahead and cut your pad to 12" (high) by 32.5" (wide).
If you're using a different kind of bucket, find its circumference and subtract about 3" to start with for the width you should cut your pad. Do a test fit and cut it down if necessary until it fits as described below. As far as height, the top of your pad should be about 2-3" below the rim of the bucket.
After the pad is cut to size, do a test fit in the bucket. Make sure you have a nice 2” or so gap between the top of the pad and the rim of the bucket. As far as width, the pad should be snug against the walls of the bucket, and the ends shouldn’t overlap. If your pad fits well, go ahead and leave it in the bucket if you like.
Next we'll get your tubing in order.
First, we'll cut the "main" tube that will lay on top of the pad and hydrate it. If you have an HD bucket, cut a length of tube to 32.75" long. If not, cut a length of tubing to the circumference of the bucket. Place one of the "arm" barbs of the plastic tee in one of the ends of the tube. Run the tube around the bucket back to the other barb of the tee, mark where the point where the tube would come to on the tee once attached, and cut it to that length.
Once you’re done, connect the tube to the “arms” of tee and you should have sort of a tube “halo” that will run snugly along the inner wall of the bucket, and sit atop the pad.
Now, we’re just gonna put in some fluffy little irrigation holes... I use a ⅛” drill bit for this operation, but you could use an awl, a nail, or any other object with a sharp, pointy end - just make sure you don’t punch through both walls of the tube. Measuring out from the edge of one of the barbs in the tube and make a hole every 4” or so the entire way around the tube. Once you're done with that, you can test it by running water from a faucet through the tube into your sink. Water should flow easily out of the holes.
If you’re happy with your holes, twist the tube if necessary to point all of the holes downwards so that they’re facing the same way as the "trunk" barb of the tee. Once the "tube halo" is installed in the bucket, both the tee "trunk" and those holes will be facing downwards.
Next, we’ll cut the tube that will connect our pump to the tube halo we just made. For our HD bucket readers - this tube will be 1'. For everyone else:
Place your pump on the bottom of the bucket. Measure from the top of the pump to the base of the tee, with the tube halo laying on the pad.
Cut the tube to the proper length, and insert one end into the "exhaust" barb of the pump (some pumps have an up arrow near it, or place the sticker behind it). Insert the other end into the tube halo. The intake/horizontal barb on the pump (the barb that's parallel with the power wires) should be parallel with the bottom of the bucket, so that it can get to that last bit of water if your bucket runneth low. If the tube length and all that stuff was fine, remove the pump from the tubing and set it aside for wiring later.
Finally, we’ll cut off a length of ducting that will get the swampy air from the cooler into your camping domicile. I’m not even an HVAC novice, much less an expert, but I believe keeping it as short as possible is the way to go, so that the cool air has less distance to travel through the ducting before it gets to the inside of your tent. Ergo, if you know where on your tent/structure the vent tubing will be coming in, you could measure or guesstimate the length of ducting you’ll need to go from the exhaust port/duct reducer to the inside of your tent.
Personally, I use a 3’ length of ducting to run from MechaSwampy 2.0 into one of the inlets of my ShiftPod and it works pretty well.
To cut the ducting, you can use your scissors to cut the foil area, but you will need your wire cutters or potentially bolt cutters to cut the "frame" wire inside the ducting.
Step 5: Soldering Stuff/Wiring
We’ll start by wiring up the DC connector. First, cut a 12” length of red hookup wire for your positive line, and a 12” black wire for your ground. Strip about ¼” on one end of each wire, and 1” on the other end. From the pictures you may notice that I used brown hookup wire for both - well, all I can say in my defense is that the author is a cheap scoundrel who only had brown wire laying around, and I have faith you can do better than me. I believe in you.
Determine which of the (usually 3) posts on the back of the connector connects to the (positive) pin, and which connects to the (ground) tab.
If you’ve never wired up a connector before, don’t worry - it’s not too hard: with the multimeter in continuity or resistance/ohms mode, place one lead on the pin inside the connector, while taking care not to touch the metal “tab” inside the connector (the shiny part adjacent to the pin in the picture of the connector), and place the other lead on one of the posts in the back. If the multimeter reads zero and/or beeps, that post is connected to the pin and is the “positive” post. If not, try one of the other posts.
It may help keep things orderly if you put a mark next to the “positive” post, and/or solder it’s wire on immediately so you don’t mix them up later. Use the end of the of the wires where you only stripped about ¼” for connecting to the DC connector. The other end of the wire with the longer exposed area will be used later to connect the pump and the fan.
Repeat the same process to identify the “ground” post, except instead of measuring the pin in the center of the connector, you’ll measure from the tab inside the connector to the posts in the back without touching the pin.
Once you’ve soldered both of the wires onto the posts, verify that they’re connected to the right connections inside the connector using the multimeter to read from the exposed ends of the wires back to the pin and tab in the connector. If everything is copacetic, heat shrink the wires to both posts individually and then, using a larger piece of heat shrink, run both wires through it and use it to heat shrink both wires together and to cover the back of the connector as well as you can. Most solder nowadays is non-toxic, but it’s a good idea to cover up the back of the connector and the ends of the wire, as they’ll be inside the bucket and exposed to moisture.
Now we need to connect the pump and the fan. First we’ll connect the fan, as it’s the closest to the power connector. Start by clipping off the plastic connector on the fan. Gently separate the wires.
Typically, I cut the blue wire so that it only extends about 2” from the fan, then I fold it back about an inch and completely heat shrink over the folded section to prevent any contact, as we won’t need it for swamp cooling purposes. Strip the red (positive) and black (ground) wires about ¼”.
Orient the black wire from the fan so that it’s running the same direction as the black wire from the power connector, or, laying on top of it, so that we can set up all of our heat shrink once we attach the fan. Solder the wires together as close to the shielded section of the black wire coming from the power connector as possible [picture] so you have room to connect the pump later. Repeat for the red wire.
Next we’ll get all of the heat shrink for the components set up, then finish up by soldering in the pump. Consider my heat shrink measurements approximate. If you stripped a little too much of the insulation on the power cables/had a solder malfunction/etc, you might need to use heat shrink that’s bigger and/or longer. Too much is definitely better than not enough, especially in this case.
Cut about an inch and a half long piece of ~0.5” heat shrink and run both of the pump’s power wires through it. Slide it down near the pump for now, so that the heat shrink isn’t affected when we solder the pump’s wires to the power connections. This heat shrink will enclose both power wires and should comfortably cover the entire exposed section of the wires from the DC connector. If you’d like an additional layer of heat shrink, go ahead and add another piece of wide heat shrink at this point.
Cut two half inch long or so pieces of ~1/8” heat shrink, and slide them over each of the wires coming from the pump. These pieces of heat shrink should be long enough that they’ll cover the the exposed section of the wires coming from DC connector, and the solder connections for the fan and the pump.
Once the heat shrink is all ready to go, we just need to solder the pump’s power wires to the ends of the DC connection wires, and then we can finish up.
Most of these pumps are made with fairly long power wires, and they should comfortably reach up to the top of the bucket with the pump sitting on the bottom. Strip about ¼” off the end of each wire. For those of you who aren’t familiar with standard wiring colors - usually these pumps will have a red wire and a red/black wire. Red is the positive wire, and red/black is ground.
Once you’ve soldered the pump to the DC wires, you can (carefully) test the pump and fan by connecting the power supply. The power supply I have listed in parts comes with a variety of connectors, and has reversible connections, so it can be handy for other devices and for troubleshooting as well. Once you attach the appropriate connector [connector description], go ahead and plug it into the DC connector and then into your power source/outlet.
You should hear the pump vibrating, and the fan should start blowing. If one or the other doesn’t turn on, make sure you didn’t accidentally reverse the connections on the offending component (i.e. soldering a positive power wire to the DC ground wire), and that your solder connections are good. As I mentioned, the power supply I recommend also has a reversible connection, so if you reverse it and your stuff works - then the connections on your DC connector are backwards. I leave it up to you if you wanna fix it, or roll with it at that point. Finally, you could just be using a connector that’s slightly too small for your DC connector, so just make sure to try the next one up.
If the pump and fan are both working, disconnect them immediately, as it’s not good for the pump to run while it’s not pumping anything.
Once you’re electrically all good, go ahead and heat shrink the individual wires, and then use that larger heat shrink to wrap it all up. At this point, there should be no exposed wire, and the large piece of heat shrink should extend a little bit past the smaller pieces of heat shrink on either side of the wires.
Step 6: Putting It All Together..
At this point, you should have:
- Your bucket, with pad inserted
- Lid, with holes for the duct reducer, mounting holes for the fan, and hole for the DC connector.
- Plastic tubing “halo”, and tube for the pump connected to the tee.
- Pump, Fan, DC Connector, all wired together.
- Duct reducer with L-brackets attached to its sides.
Start by connecting the fan to the lid. Make sure that the label on top of the fan is pointing upwards/towards the hole in the lid.
Screw on the duct reducer/exhaust port.
Look down into the duct reducer and make sure that the fan looks centered/properly oriented before moving on.
Next, unscrew the little ring nut around the DC connector, and fit the connector through the lid. Screw it on using the ring so that the ring is resting on the top of the lid once it’s screwed on.
Connect the vertical tube to the pump.
Lower the pump in until it’s resting on the bottom of the bucket, and the tube halo is sitting on top of the pad.
Close the lid.
CONGRATS! Now you’ve got yourself a swamp cooler. When you’re ready for some swamp cooling, just open the lid and fill water to below where your holes are, close it up, attach your ducting and power it up. Make sure to place it outside your tent on the shady side if possible. If you go to weeklong events in the desert, I would budget maybe a quarter of a gallon of water for it per day, if you only run it morning 'til midday.
Hope you enjoyed building this thing.
Step 7: A Word on Power
I received a good question regarding how to power these units when out in the field. I'll address what I think are the most common and workable options, and describe how you would go from there. Please note, I am not suggesting any one power source/product over another. I will say, unless you have a ton of other stuff to power, a gas-powered generator is massive overkill for this, but beyond that - it's your call.
If you'll be using solar power, make sure that the panel you use can reliably produce at least 60 Watts of power for at least 4-5 hours during the day.
Commercial/"Off The Shelf" Solar Power (what the author uses): I have an all-in-one solar battery/controller that I use with a 100W solar panel. The solar battery/controller unit has a 3-prong North American 112 VAC outlet which I plug the power supply (listed in the parts section) into. If this is similar to what you'll be using, get the power supply I listed (or any other good 60W 12VDC power supply) and you'll be good to go. My unit has an on/off button for the AC outlet, so that's what I use to turn the swamp cooler on/off from inside my tent. If your power unit doesn't have a button, you'll need to manually insert/remove the power cable to turn the swamp cooler on/off.
DIY Solar: A cheaper, yet perfectly viable option for powering these. You will need a solar panel, charge controller that will output 12VDC, and deep cycle 12V marine battery. Setting that up is beyond the scope of this article, but *instead* of buying the power supply in the parts listing for the swamp cooler, we'll just be making a DC power cable like so:
- Get a Male DC Connector/Plug. Ensure that it fits well into the Female DC Connector you purchased.
- Make sure you have an additional 3-6+ feet of Red and Black wire (or more specifically - enough to make a cable that goes from your swamp cooler to where the charge controller is stationed), and enough shrink wrap for another connector. I would also consider electrical tape, zip ties, cable ties, or a cable sleeve for keeping the two wires together for safety/trip hazard elimination purposes.
- Solder the wires to their appropriate counterparts. (If you buy a male DC "plug", they usually have black and red wires connected to the connector, and you'd just to solder wire to wire. If you buy a "connector" it will likely just be the connector, and then you'll need to identify the posts similarly to how you did for the female connector for this swamp cooler.)
- I would definitely heat shrink both red and black wires, heat shrink them together, and potentially do an additional layer of heat shrink. But keep the length down to 3/4" at most so that the wires have some flexibility near the connector(s).
- Secure the wires together using your zip ties/cable ties/tape/etc for the length of this power cable back to the solar charge controller.
- The bare power and ground wires will plug into the solar charge controller. Typically, there is a set of connections with a light bulb or fan symbol above them on most charge controllers where you'll plug these wires into.
- To turn the swamp cooler on/off, you'll have to manually plug/unplug the power cable from the swamp cooler, unless you add a switch to the cable.
Gas-Powered Generator: In addition to being an overkill option (most of them easily produce 200W+) this is also the loudest and riskiest option. If you are planning to power this cooler with one - make sure the generator is far, far away from where this swamp cooler will be sucking in air. That said, here's what you'd need to do:
If the generator has a 3-prong North American 112 VAC outlet, buy the power supply listed in the parts, and a super long extension cable.
If the generator only has DC outlets (e.g. the "cigarette lighter"/auto DC connectors) I would try to find a very long DC Male-to-Female auto cable, cut off the female connector, and solder on a male DC barrel connector, similar to the DIY Solar power cable.