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3D Printing a Functional Boat with Post-Consumer Milk Jugs

3D Printing & Imaging

WOOF with the Boat
A portion of the WOOF Team with their 3D Printed boat.

Last summer a student organization based out of the University of Washington, WOOF (Washington Open Object Fabricators), successfully created the world’s first 3D Printed Boat. The boat was printed on a large-format Fused Deposition Modeling (FDM) printer, which was hacked together from a plasma cutter, and prints with post-consumer milk jugs.

The plasma cutter, known as “Big Red”, was donated to the group and converted into a printer with a massive 9 x 4 x 3 ft build area. The group had two months to get it functional and enter a boat into Seattle’s Annual Seafair Milk Carton Derby.

Racing at the Seafair Milk Carton Derby. Note the traditional carton boat to the left.

Milk jugs are made of High Density Polyethylene (HDPE), which despite being a fantastic material to make things out of, is not easy to print with. HDPE doesn’t adhere well to anything aside from hot HDPE and it shrinks substantially as it cools. To solve the first problem, the WOOF team built a unique build plate (pegboard with countersunk holes) to achieve a mechanical bond, and attached a heater to the extruder to soften the previous layer.

Printing quickly prevents the shrinking tendency of the plastic from becoming too much of a problem, but pausing the printing process for half a day allowed the walls of the boat to shift. The team ended up adjusting the CAD model in order to complete the print after the pause and printed a sacrificial flange with the boat, which was screwed into the bed, to further prevent warping.

The slideshow below includes a few images of the process:

The WOOF team is currently working on Version 2 of the boat for this summer’s competition, and they’ve made some improvements to the machine and the design. Instead of using pegboard for the build plate, they’re using a fused-HDPE surface, which already seems more promising. The boat itself will be printed in four sections, so the team can obtain the desired curvature for maximum performance.
A CAD model of Version 2 of the boat.

Thankfully, three WOOF members didn’t let their interest in large-format printing end there. Brandon Bowman, Bethany Weeks and Matt Rogge won techfortrade’s 3D4D Challenge in the Fall with a proposal to start a company that manufactures cheap, large-format (at least one meter cubed) FDM printers to aid developing areas. These areas will be able to print necessities like composting toilets by simply recycling their plastic waste as printing material in the machines.

3D4D Team
The winning 3D4D Team — Faculty adviser Duane Storti and team members Brandon Bowman, Bethany Weeks and Matt Rogge pose with Big Red. Photo from the University of Washingto.

Here’s hoping the Version 2 build goes smoothly and the WOOF team does well at the race in July!

20 thoughts on “3D Printing a Functional Boat with Post-Consumer Milk Jugs

  1. jamesb says:

    Freeship is a great tool for hull design. I used it to design and build a little rowboat (see Make photo pool about five years ago) that handled really well. I would be nervous paddling that little Pirogue out on open water like this team did. But as a 3D printing HDPE boat proof of concept, it is pretty interesting, and quite an accomplishment. Their next canoe looks like it will handle a little better, but is going to need more bulkheads in the middle, to keep it from flexing out. If each section was printed as a watertight box with bulkheads on the ends, and they were fused/fastened through the bulkheads, it would be stiffer, and keep the fasteners out of the water.

    1. Brandon Pomeroy says:

      Hi James, thanks for your comment!

      You’d be right to be nervous about paddling our little boat around; I’ve tried it, and it’s really cutting it close to sinking! Due to some issue with shrinkage from the HDPE, our calculations on the buoyancy were slightly off. But we’re proud of it because it’s a stepping stone to bigger and better things. Gotta start somewhere!

      And I agree on adding in bulkheads, but that is, unfortunately, not possible with the current design . This is due to the limitations of 3D Printing without support material; we can’t print into thin air. We didn’t want to do another flat bottomed boat, so we have to print all the sections vertically. The finished product is surprisingly stiff, however, so we’re not at all worried about flexing. It’s pretty amazing the amount of strength these milk jugs put out!

      1. James Amberson says:

        I have a question about the bulkhead idea vs the limitations of 3d printers… a work around for building a bulk head that “comes out of thin air” in my head would be just to build the entire boat sideways..

        so the finished product is a boat on its side, (you might need to put in some support structure that holds the weight of the boat as its being built but you can cut/sand it off after it is done being printed).. but the bulk head (which I assume is just a bar that connects the top of the walls of the canoes, or maybe even a build in chair) could be built vertically this way couldn’t it?

        I am EXTREMELY interested in this kind of stuff. I intend to learn more so that someday I can build a boat out of plastic myself.

        Thank you in advance for your wise reply


  2. badaztek says:

    It is great to help developing areas to improve their lives, but sadly no matter what their politicians say, they are never going to permit them to improve their lives, they are going to keep them exactly where their people are at to keep control of them, and to continue living high on the hog off of their breaking backs. The machines will be there for a few days to get videos and to show how the politicians is so hopeful for their future and as soon as everyone that can cause trouble for them is gone, they take the printers and either scrap them out and pocket the cash, put them in a factory someplace and use them to produce high profit items, or sell them to warlords who will use them for the warlords own devious means, sadly the people who it is meant for, will never see any improvement in their lives.

  3. E. Scott M. says:

    How did you recycle the jugs? I have thought about useing them but have not come up with a answer to how to refine them into a useable base material again. I also agree with jamesb about the bulkheads/crossmembers, you need something to help it retain your shape.

    1. Brandon Pomeroy says:

      Thanks for your questions, Scott! We first collected the jugs and washed out all the milk inside. Then we removed all of the paper labels on the jugs. Hit the paper with some hot air from a heat gun for a few seconds, and it will peel right off. We then shredded all the jugs down to a nice flake (about .5 cm^2), using some industrial strength shredders.

      Once it’s in this flake form, it goes through our extruder quite nicely!

      I addressed the bulkheads issue in my reply to jamesb, but it boils down to limitations of the printing process. Thanks for your concerns!

  4. Charles J Labedz (@pheadrus0110) says:

    How about printing a largish (40′-60′) sphere for seasteading. internal partitions for flooring and ballast….

    1. Brandon Pomeroy says:

      That would be… ambitious! There are easier (and cheaper!) ways to manufacture something on that scale, especially if you want to make more than one.

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Eric is a Mechanical Engineer with interests in machining, mass manufacturing, product design and kinetic art. While not building things, he enjoys skiing, cycling, and juggling.

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