Introduction: Build a Milk Jug Raft!

Picture of Build a Milk Jug Raft!

This Instructable will describe the construction of a heavy duty milk jug raft built out of recycled materials and capable of supporting over 700 lbs. The product is a fun craft for lakes, rivers, and swimming pools alike.

I've actually entertained the idea of building a milk jug raft for a while, but it took a few years to gather all the milk jugs, so I've only now been able to complete the project. I found it to be highly rewarding and extremely satisfying... there is something innately fun about building a raft and having adventures like those found in the wonderful story of The Adventures of Huckleberry Finn. As Huck says, "It's lovely to live on a raft. We had the sky up there, all speckled with stars, and we used to lay on our backs and look up at them, and discuss about whether they was made or only just happened." I personally don't live on my raft, but I had an incredibly peaceful and relaxing experience lying in the middle of a lake gazing up at the sky. The raft is 100% worth the minimal effort needed to construct it.

This project carries no cost and can be easily completed by anyone who can use a drill and basic hand tools. It will take a few months to a few years to save the required milk jugs, but a speedier option would be to gather them from recycling days and friends. Alright - enough with the talk, let's get shipbuilding!

Step 1: Collect the Milk Jugs

Picture of Collect the Milk Jugs

The first step is to evaluate the best option for flotation and collect the floats. Although this is a milk jug raft, yours doesn't have to be - I just used milk jugs because my family goes through about 6 gallons per week, so they were plentiful. Alternately, you could use two-liter carbonated drink bottles, or any other strong plastic container. You will need a lot, so keep that in mind when choosing your flotation method.

Next, you will need to determine how many to collect. This is based on desired buoyancy and on whatever size goal you set. If you want a certain size raft, just measure a milk jug and use the basic length times width calculations to figure out how many you need for a certain size raft. This works well, but a better method is to set a goal for milk jug collection based on how much buoyancy you want in the end. There are some really neat physics calculations that govern buoyancy and displacement (how much water your craft pushes out of the way), and they are super simple! Just take the volume of your container (1 gal=3.785 liters) and convert it to liters. This will not work with imperial units, which is why the United States should switch to metric. :) After converting your volume to liters, simply replace the word "liters" with "kilograms." That's it! That is how much weight one milk jug will support - 3.785 kilograms, or 8.345 lbs. With that knowledge in hand, you can just divide your target buoyancy capability by that to find out how many milk jugs you will need.

To estimate a target buoyancy, I recommend about 50 lbs for the raft itself, your weight and an estimate of any potential guests' weights, and 20 lbs for miscellaneous. However, that will just barely keep your toes above the water. Really, you should use about 1.5 to 2 times that weight - this will keep you dry and provide a safety cushion of buoyancy. I decided to use 84 milk jugs.

Once you know how much bouyancy you want or how large a raft you want, start collecting! Use whatever resources you have - recycling bins, family, friends, work/school, etc. The more places you have giving you milk jugs the faster you can get building!

Step 2: Bind the Milk Jug Modules

Picture of Bind the Milk Jug Modules

Once you have a huge pile of milk jugs sitting around somewhere in your house and taking up a lot of space, you will be very motivated to use them for something. That is great!

I built my raft by making four-jug modules that were taped together. These were easier to handle than single milk jugs and were also symmetrical, which made attachment fairly straightforward. To make the modules, assemble scrap wood into a square with inner dimensions of 12", or whatever two of your milk jugs measure side by side. Next, place four jugs in the jig with their handles facing inwards. Use a rubber band to hold the tops close to each other.

To finish the module, measure four feet of duct tape and cut it a little bit long. Pulling tightly, wrap it around the four milk jugs about halfway up. Make sure to smooth it down well. After removing the rubber band, you have a finished milk jug module! Congratulations! You only have a gazillion more to do...

Step 3: Lay Out the Raft

Picture of Lay Out the Raft

Next, you should determine a rough layout for your raft. Decide on the basic shape, etc. I decided to go with the simple solution and just make three pontoons side by side, but this design leaves a lot of room for improvement. For example, it is a bit wobbly side to side. One possible fix would be to place the outer pontoons on outrigger-type structures, so that the three pontoons would have space in between them. The deck boards would then cross all three pontoons, just like they do in my raft design.

You could also choose a different design and make a square raft, or a taller raft, or even a monstrous floating island.

Whichever design you settle upon, decide how long your boards will have to be to connect all your milk jugs together. I made mine around 14 feet long - this enables me to make three pontoons with 7 modules each for a total of 84 milk jugs, 28 on each pontoon. Measure and cut your boards (I used scrap 2x4s), then proceed to the next step.

Step 4: Make the Pontoons

Picture of Make the Pontoons

I'll be honest - this is the most boring step part the whole project. It goes much faster with a good set of tunes playing in the background, though.

With your mountain of milk jug modules ready, you can make the pontoons. I used nylon string tied through the inward-facing handles of the four milk jugs in each module to attach them to my 2x4 pontoon boards.

It is somewhat tricky to get the milk jugs to stay, and even harder to make the nylon string not slip, so don't give up if it takes a few tries to get it right. I passed the string (with fused ends) through two of the milk jug handles (going from one side of the board to the other), then up, over the board, and back to the side it started on. I then threaded it down and through the other two handles (again going from one side of the board to the other, not parallel to the board), then back up and over the board to meet the other end of the string. Hopefully the pictures help. :)

Then, I tied the string on top of the board (in the middle of the X formed) using a triple knot. From Wikipedia, this seems to be a granny knot with another knot on top. Make sure to pull the string as tight as possible before doing this! Nylon string is extremely slippery and WILL undo itself if not triple-knotted. Once the knot is done, fuse the ends of the string with a lighter.

If you've got one module attached, you are totally capable of doing all the rest! Just keep the tunes rolling and don't forget to pull the string tight. Also, make sure to push each module up against the already-attached ones so that you don't run out of space on your pontoon board. Your finished pontoon should look approximately like the one in the last picture.

Step 5: Add Planks

Picture of Add Planks

Once you have all your pontoons made, line them up according to your design and measure the distances you will need to cover with planks. For me, since my raft was a rectangle, it was prettty easy - just a bunch of 32" 2x4s. You should plan to have one plank per row of milk jugs - i.e. I used 14 planks since I had a 6x14 array of milk jugs. The planks serve a triple purpose - they provide a walking/sitting surface, hold the pontoons together, and press down on the milk jug caps (which are slightly above the surface of the pontoon boards) to exert tension on the string and keep the milk jugs from flopping around. When you have determined the number and length of planks needed, cut them. You don't have to use 2x4s - you could use thinner boards for less weight.

Assemble your pontoons in the correct formation and then use one screw per pontoon to attach the just the end planks. Now you can make sure that the raft is square. Once it's square, add another screw to each of the pontoon-plank intersections. I also added two planks evenly spaced in between the end ones, with two screws per interesction.

If you continued like this, you would spend a long time screwing down planks, which would grow quite loathesome by the time you were done. So, to speed up the process and save on screws, I only used three screws per plank for the rest of the planks, rather than six. The raft is still quite sturdy. (Two-by-fours may have been a bit excessive for planks, hmm?)

Step 6: Sand and Paint

Picture of Sand and Paint

If you used scrap wood like me, it is probably really rough and not pleasant to sit on. So, to remedy that problem, pull out your dusk mask and sand it for all you're worth!

An orbital sander will make your job much easier, but sandpaper will also work. I started with 80 grit and then went up to a 120 grit for a smoother finish. The difference was quite apparent, and I felt much more confident about sitting on it and not getting splinters.

Once the raft is sanded to your liking, paint it with a durable exterior paint. It will get wet and see some roughing up under your shoes, so interior paint probably won't make the cut.

Step 7: Make the Paddle

Picture of Make the Paddle

Since I didn't have a canoe or kayak paddle, or even a rowboat oar, I had to get creative and use what I had on hand. I used an old squeeze mop and a cabinet door to make a really nice paddle.

To do this, I removed the mop part of the mop and was left with the handle and the bracket at the bottom of the handle. I had a space left between the sides of the bracket, so I made some washers (using a hole saw) from a piece of plastic I had lying around. The plastic was made by cutting up milk jugs and then melting and pressing them into a sheet of hard, rigid plastic useful for many projects. There is a pretty good Instructable on that subject here. It says to use a pot of oil to melt the plastic; I just used a parchment paper-covered cookie sheet in my oven.

I did 45° cuts on the corners of the cabinet door to improve its aesthetics and then used the plastic washers and the bracket to attach the door securely to the mop handle. Finally, I gave it a quick coat of polyeurethane for waterproofing.

If you have a paddle, oar, or other means of propulsion (battery powered outboard motor, anyone?), by all means, use it. Otherwise, find a handle and something flat, and let your creative side shine!

Step 8: Add Pizzazz!

Picture of Add Pizzazz!

A white raft floating on white milk jugs would probably be described by Huckleberry Finn as "mournfully dull," so in the spirit of adventure, pirates, and boyhood fancy, let's add some pizzazz with a pirate flag!

To make your flag (it doesn't have to be a Jolly Rodger), take a scrap of cloth or a pair of unwanted pants and cut it to size. I used about 16"x12". Next, if it is to be the dreadful skull and crossbones, crumple one end of it and cut it with scissors to make a tattered edge for effect. If it is synthetic, lightly fuse the edges with a lighter to prevent unravelling.

Lay out your design by drawing the outline of what you want in chalk, or with a pencil. Fill it in with paint - I just used the same paint as I put on the raft planks. Once one side dries, flip it over and do the same thing on the other side.

I found that a gardening stake worked well as my flagpole. If you don't have one, just buy a dowel rod. To secure the flag to the pole, fold one end over the pole so it wraps around, then pin and sew it. The finished stitch can be seen in picture 7.

Next, drill a hole in one of your raft planks or pontoon boards to fit the pole. Hot glue a stop (I cut mine with a hole saw) onto the pole at the correct depth to prevent the flag from sinking too far into the hole.

Finally, give your new raft a good name! I christened mine The Thirsty Pirate, which I think is quite fitting.

Step 9: Set Sail for the High Seas!

Picture of Set Sail for the High Seas!

Step back and take in your handiwork! You have just built a sturdy watercraft, capable of supporting lots of people! Find some water and set sail for magical adventures on the high seas!

Hmm... actually sailing this craft into the ocean may be hazardous to your health and is thus not recommended. Nevertheless, fantastic adventures await you and your newly christened pirate raft! Have fun, be safe, and unleash the Huckleberry Finn (or Tom Sawyer, if you like) inside you!


SamDavisson made it! (author)2017-06-07

I took the slacker approach and tore the boards off one side of 2 palates, then nailed them together. Then I put milk jugs in bottom side toward the top of the boat and covered the bottom with an old tarp I stapled on. Holds me and a friend, about 260lbs. Thanks for the detailed write up though!

momoney5704 (author)2016-06-02

is the only way to get the plans to pay for the go Pro version?

No, you should be able to view all the steps without even having an account. Enjoy!

Aaron42 (author)2016-05-07

Here is the basic structure of it. On top of this I drilled 25 holes and then inserted screws to two sheets of 6X4 plywood. The screws go all the

PopsicleGhoul (author)Aaron422016-05-08

Wow, that is really impressive! I love your design! I bet your raft has also more stability (less rocking side to side) because it is wider.

Aaron42 (author)2016-05-06

I built this and improved on the design. It is 8X6 with 144 milk jugs. I used flexi pvc board to connect rows of jugs and 2X4s to connect the pvc board. I made a full deck on it with 2 sheets of plywood. Weighs almost 200 pounds. Thanks for the idea.

PopsicleGhoul (author)Aaron422016-05-07

Cool! It's fun to see that someone built this. Do you have any neat pictures?

bdemers1 (author)2015-08-11

Awesome Job! Maybe add a chair and a slightly longer paddle and this would be great. How much does this weigh?

PopsicleGhoul (author)bdemers12015-09-05

Sorry about the delay in getting back to you. The raft weighs 58lbs, or 26kg. It can be lifted by one person. However, it is unwieldy, so it is easier to lift with a person on either end.

Laura Cullen (author)bdemers12015-08-11

How about a Milk Jug Mississippi River Paddle Wheel Raft. Just an idea from addled mind: center hole for protruding feet to operate bicycle wheels and keep seat at nearly raft surface level. Long axle from center pedals to outside edges where bicycle wheels customized with paddles can fit & function unobstructed. A tiller of some kind within reach of captain to guide vessel down/up river. And of course some kind of loud horn or calliope noise like we have on the New Orleans River Boats. And a waving flag or two to attract attention in case you need more.

That is an absolutely terrific idea! I love how you got into the spirit of the book that inspired this! I will have to add these modifications when I get time and post an update.

Mugsy Knuckles (author)2015-08-18

I realize that this suggestion might seem counterintuitive, considering all the time spent sanding, but if you mix a little bit of sand into the paint, it creates a far less-slippery surface than just plain paint. Think of the grip tape on a diving board.

Of course falling off a raft because it's slippery is usually not a big deal, and might in fact be part of the appeal.

That is a really cool idea! I think I'll have to try that sometime.

jeanniel1 (author)2015-08-17

This is SOOOOOOO great - and I can see a bunch of kids making this and taking it out on their creek! I love how you created the paddle. I wonder how it was to maneuver the raft on the water? Would a rudder help?

PopsicleGhoul (author)jeanniel12015-08-18

Thank you! I would rate the maneuverability at medium - it wasn't as easy as a canoe, but it was doable when I got the hang of it. I found that alternating paddle strokes on either side of the raft made it spin a lot (no keel), so I sat on the front of the raft and paddled from there (pulling the paddle toward the raft and then to the side in a J motion). A rudder would probably help. :)

nwonharp (author)2015-08-12

Yeah I like it ! You could probably save a little work and expense by using a ready-made pallet for the frame . ( if you look around , a lot of times you can get them for free ! ) Soda bottles , or most any plastic bottles should work . although having bottles of different shapes and sizes would make the construction a bit more difficult . I suppose you could put them in bags or something !

Cheers , take care , and have a good day ! 73

PopsicleGhoul (author)nwonharp2015-08-16

A ready-made pallet would be a great way to recycle! Also, you had the same idea (bottles in bags) as another man, although his construction was a much grander affair than a simple raft. I highly encourage you and all who read this to check out his floating island:

nwonharp (author)PopsicleGhoul2015-08-17

Yes , I have seen that one . I guess " whatever floats your boat " or raft will work ! The raft you made looks nice , with everything being symmetrical and neat . Any plastic bottles will float ( pop bottles , household cleaning products bottles , etc ) . another source of buoyancy could be scrap styrofoam ( from construction etc ) or even packing material , if you have enough of it , like bubble pack or or those annoying " plastic peanuts " that come in every shipping carton . A friend of mine made a boat dock out of discarded plastic 55 gallon drums ! Recycling , or re-purposing is a good thing .

Cheers , take care an have a good day ! 73

OlmoF (author)2015-08-11

Nice instructable!

I would just suggest to keep the bottles upside down, so that in case of damage there is no escape for the air to go on the top

PopsicleGhoul (author)OlmoF2015-08-16

Good idea, but the water might seep in through the cap threads. I didn't do anything to hermetically seal them, since the caps are above the water line.

OlmoF (author)PopsicleGhoul2015-08-16

The pressure of the air in the milk bottle will only allow some water to seep in, just like a upside down empty glass will not fill when put underwater or like a diving bell :)

PopsicleGhoul (author)OlmoF2015-08-17

Ahh... thanks! I love this physics stuff.

PedroC14 (author)OlmoF2015-08-11

very good OlmoF

Bowtie41 (author)2015-08-13

My biggest scare would be lid popping.Even when I smash them to save space for recycling the lids are hard to get to stay on due to only about 1/8" of threads.I would use some sort of soda bottles or rinsed out bleach jugs,etc,due to the much more robust thread engagement.

PopsicleGhoul (author)Bowtie412015-08-16

Good point! I couldn't find equally large quantities of the other types of containers, so I settled with milk jugs. Also, the strain imposed on any one milk jug is spread out, so no one jug gets too compressed.

Aunt Jane (author)2015-08-12

Avoid water jugs and stay with milk jugs. Water jugs are biodegradable and breakdown VERY fast. I was carrying water to my garden and picked up a jug of water and it just shattered.

PopsicleGhoul (author)Aunt Jane2015-08-16

Thank you for the helpful tip! Going down in the middle of a lake wouldn't be fun. :)

grigsby (author)2015-08-11


You know pop bottles are more durable with thicker walls. I have been thinking about pop bottles for a time. Just weigh one full. and multiply by the number of bottles minus the weight of all floor and rigging and you will have an estimate of capacity of unit. Or take the load you want to carry, add 50% to 100% safety factor. divide by the weight of full pop bottle. Pop bottles are not as wide as milk bottles so you may need wider and/or longer frame. Duct tape may be the thing to use to assemble raft. I like idea of paddle wheels on rear but that is another day. Have fun.

PopsicleGhoul (author)grigsby2015-08-16

Certainly, if one has access to large quantities of pop bottles, those would make an even better choice than milk jugs, since they have sturdier walls (rated for pressure) and also have better threads. However, my family hardly drinks pop at all, so I couldn't do that.

smoss20 (author)2015-08-11

You may lose stability within the bundles, but you may want look into spacing them out some - Just for a Wider Footprint. Looks like a lot of fun. I might need a motor though.

PopsicleGhoul (author)smoss202015-08-16

Yeah, a sort of outrigger system (like a catamaran) would almost certainly fix the wobbling problem. If anyone tries that, be sure to post pictures! I bet a milk jug catamaran would look terrific!

lovethebackwoods (author)2015-08-11

This is absolutely one of the most enjoyable reads (for a project I'll probably never do) that I've had in a long time! I tried making a raft from scrap wood when I was a pre-teen, but had no real notion or appreciation of how to go about it. The balance was off and it failed to do its job. It was sure a lot of fun then, though. I wish I'd had this Instructable then - but that was countless decades ago and definitely pre-computer days! Keep writing your great 'ibles, sir! Good on ya!

Thank you for the compliment! I enjoy writing. Also, I've always wondered about those all-wood rafts written of in Mark Twain's books and in shipwreck novels. Maybe one day I will build one of those and make another 'ible.

nolan.kriegel (author)2015-08-11

Very good, but my concern is that milk jugs seem to puncture very easy. I have always wanted to do the raft but I was going to use large PCV pipes. Maybe 4" - 8". and then put a small motor or some kind of pedal driven paddle, or propeller.

Maybe someone can use my idea and do it, I am older now 70 and still have to many household projects.

Good improvement! PVC would definitely be a more durable option. I also like your idea for a paddle. I mig try that.

TXMess. (author)2015-08-11

This looks like so much fun!

PopsicleGhoul (author)TXMess.2015-08-16

It definitely is a lot of fun! There's nothing like lying on a gently rocking raft under the stars. :)

iantgray (author)2015-08-12

cool idea!

Eyad_moh (author)2015-08-12

Wonderful and inexpensive idea .... You are a lucky man you are in a very beautiful place

mcnapper1 (author)2015-08-11

I am also wondering MFein if you have read the "be nice" comment policy. It means the same in any language. Play nice, speak nice, or just don't do anything.

Just saying...

bkasa (author)2015-08-08

This is one of the coolest things on here lol but i don't have that much jugs xD

Laura Cullen (author)bkasa2015-08-11

Inner tubes, the bigger the better.

xylexx55 (author)bkasa2015-08-11

I had a school project that required a lot of milk jugs. I hit up my local Starbucks and scored two large garbage bags full of them!

PopsicleGhoul (author)bkasa2015-08-08

Thank you! Also, if you want to do the project but don't have the enormous pile of milk jugs, ask family and/or friends to save them. Otherwise, a quick scavenge on recycling day should yield a bunch of containers.

CJA3D (author)2015-08-10

Awesome!! For how long have you been collecting milk jugs :)..

Pirate_Prince (author)2015-08-10


Thanks for sharing.

ShakeTheFuture (author)2015-08-09


kdee1995 (author)2015-08-08


nathanaloysiusbash (author)2015-08-08

This is awesome. I love the pizazz. Can I be huckleberry sawyer? Your family drinks a lot of milk.

Thank you! I had fun making the raft and being inspired by Mark Twain's great book. Also, my family is somewhat large, so that helps in going through more gallons of milk per week.

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