Introduction: PVC & Duct Tape Kayak

By 30+ STEM Projects for Kids
About: I'm a writer, maker, and educator who's on a mission to better the world through hands-on engineering projects. Check out my work: www.stem-inventions.com/

If there’s one project that will cause your friends and family to realize you’re a PVC and duct tape genius (and perhaps a little crazy), it’s this one. The PVC & Duct Tape Kayak is truly an epic project that requires no less than 10 rolls of high-quality tape to build, as well as a great deal of diligence and determination. However, getting the kayak out on the water and successfully paddling across a lake may be the pinnacle of any PVC engineer's career.

This project is an excerpt from my book Duct Tape Engineerand adapted for Instructables (published by Rockport). If you're into epic-sized duct tape projects, go check it out!

Step 1: Tools & Materials

Everything you need (and the order you'll use it in)

Substitutions:

  • PVC pipe cutters: You can use a fine-tooth saw to cut PVC, however I strongly recommend that you buy a pair of PVC pipe cutters. They will save you an enormous amount of time and energy and it won’t create any PVC dust.
  • Pipe pliers: Smaller pliers or vice grips
  • Mallet: Small hammer, but use it gently to avoid breaking the PVC

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Step 2: Prepare Your PVC and Workspace

Get Ready! Organizing your materials and work space in the beginning of this project will save you a lot of time.

1. Assemble a bunch of empty boxes or containers. As you cut the pieces of PVC in step 2, use the boxes to sort the pieces by length.

2. Cut the pipe pieces. Write the pipe measurements on each piece as you cut them. You’ll need:

  • One 24.5" (62.2 cm)
  • Six 24" (61 cm)
  • One 23.5" (59.7 cm)
  • Twenty-two 18" (45.7 cm)
  • One 17.5" (44.5 cm)
  • One 17" (43.2 cm)
  • One 16" (40.6 cm)
  • Five 15" (38.1 cm)
  • Two 12.25" (31.1 cm)
  • One 12" (30.5 cm)
  • Two 11.25" (28.6 cm)
  • Two 8.5" (21.6 cm)
  • Ten 6" (15.2 cm)
  • Fourteen 3" (7.6 cm)
  • Thirty four 1.75" (4.45cm)

3. Label the containers according to the length of the pipe.

4. Organize all of the PVC connectors into separate small containers.

5. Choose a work surface that is level and at least 10' x 10' (3 x 3 m). An uneven work surface might result in an uneven kayak. PVC primer will stain most surfaces, so cover your work surface.

6. Place the cans of PVC primer and cement on a scrap piece of cardboard or wood. This will prevent the cans from tipping over if the plastic shifts underneath them.

7. Carefully read the instructions for your PVC primer and cement. Different brands have different cure times and other specific instructions.

8. Finally, be sure to wear clothes that you don’t mind getting stained!

Step 3: A Note on Fixing Mistakes

Mistakes are inevitable with a big project like this. Be sure to purchase extra pipe in case you cut a piece incorrectly. When building the kayak, if you glue the wrong piece in and it’s too long, simply cut it shorter. If it’s too short, then use a 1/2" (1.27 cm) PVC coupling to extend the pipe.

Step 4: Create the Center Strut

TO VIEW FULL SIZED IMAGES: Click on the image, then click on it again. You'll see that you can then view it in larger sizes. This will make it easier to see the pieces and measurements.

1. Construct the center strut of the kayak using the specific lengths and connectors shown. Start with the pipe and crosses. Press each cross piece flat against the ground as the PVC cement cures to ensure that the crosses are level, one to the next.

Step 5: Widen the Center Strut

2. Glue the 90° elbows on the very ends of the center strut. Dry-fit a piece of pipe into the elbow before the solvent cures. Use it to check that the connector is pointing straight up.

3. Glue a 3" (7.5 cm) pipe into the center-most cross, and the one to the right of it. Glue 1.75" (4.45 cm) pieces of pipe into the left-of-center cross piece.

4. Glue two pairs of pipe and connectors (highlighted in blue). Glue them into the 3" pipe pieces. These will reinforce the center of the kayak and provide a stable seating area.

Step 6: Taper One Side

5. This step is a little tricky.
It helps to have a partner to hold on to a 24" (61 cm) length of T-Rex tape for you as you glue. If you’re building solo, place the cut piece of tape somewhere accessible. Glue the remaining tees onto the 1.75" (4.45 cm) pipe that was added to the left-of-center cross in the last step.

While the glue is wet, wrap the connection with the piece of T-Rex tape as shown. This will prevent the connection from coming undone as the glue cures and will aide in creating the kayak’s tapered shape.

Step 7: Create the Lower Frame

6. Create the kayak’s bow and stern. Glue a 12" (30.5 cm) piece of pipe into the front 90° elbow. Glue a 16" (40.6 cm) piece of pipe into the back 90° elbow. Glue end caps onto the tops of those pipes.

7. Glue 1.75" (4.45 cm) pipe into every open tee and cross connection. Glue 45° elbows onto each. Glue 6" (15.2 cm) pipe into the eight left-most 45° elbows. Glue the two 8.5" pieces of pipe into the back right-most elbows as shown.

As you glue in each 45° elbow, dry-fit a piece of pipe that’s at least 12" (30.5 cm) long. Use the pipe to gauge whether each elbow is perpendicular to the center strut. Adjust the elbows so that they are perpendicular before the glue cures. Remove the dry-fit pipe and use it again for the next elbow.

Step 8: Create the Lower Frame (cont)

9. (Picture 1)Create two side struts shown. Make sure all the crosses are level, one to the next.

10. (Picture 2) Glue the three center-most crosses of one side strut onto the frame.Do not glue on the other connections yet. Repeat on the other side. Wait for the minimum curing time before handling. The next step will bend the existing pipe and put tension into the frame, so it’s important that the solvent has cured enough to handle the strain.

11. (Picture 2) Get a partner again! Working both side struts at once, prime, glue, and affix the right-most crosses at the same time. (It’s more difficult to do this one at a time). Repeat with the left-most connections.

Step 9: Create the Upper Frame

12. Glue 45° elbows onto each of the crosses. Make sure the open 45° elbow connections are pointing straight up. Glue 6" (15 cm) pieces of pipe into the center 45° elbows. In the remaining eight 45° elbows, glue a 1.75" (4.45 cm) piece of pipe, a tee, and 3" (7.5 cm) piece of pipe.

Make sure the side-facing connectors of the tees are pointing toward each other. If they’re not, it will be difficult or impossible to attach the cross braces in a later step.

Step 10: Create the Upper Frame (cont)

13. Assemble the two top struts separately. Make sure the tees are pointing either straight down or straight across as shown. As you build, dry-fit pieces of pipe into the open connection of each tee. This will help you see whether or not the open connections are perfectly square relative to each other.

14. Following steps 10 and 11, glue the three center-most connections onto the frame, then the back-most pair, then the front-most. The frame shell is done!

Step 11: Install the Cross Braces

15. (Picture 1) Create two special cross braces by gluing a tee, 3" pipe, end cap, and two pieces of pipe as shown. These will help form a tented deck later on.

16. (Picture 2) Attach all of the cross braces as shown. Your frame may have slight variations in width. Dry fit the cross braces before gluing them in, to make sure they will maintain the kayak’s tapered shape. Once you confirm the fit, use a mallet to tap out one end of the pipe, then use a pipe wrench to twist and pull the pipe out of the connector.

17. When you’re ready to attach the braces permanently, start by gluing only one end of each brace into place. Then, working from the back toward the front, glue the other end of each brace into its connector. Use a mallet to tap in the pieces firmly.

Step 12: Tie Off the Ends of the Frame

18. Attach the side struts to the bow and stern of the kayak: Drill a hole through each side strut, about 1" (2.5cm) from each end. Drill one hole through end cap, and a second hole about 4" (10cm) from the bottom of the stern. Repeat, drilling through the pipe that forms the kayak’s bow. Attach the struts to the bow and stern with cable ties as shown.

19. At the bow and stern, wrap T-Rex tape around the lower left strut, around the upright, and around the lower right strut. Repeat with the upper strut.

TEST THE FRAME STRENGTH

The kayak frame is finished! Before moving on, first, wait 24 hours for all the glue to fully cure. Next, test the strength of the frame with a friend by doing the following:

Place two chairs about 10' (3m) apart. Rest the bow and stern of the kayak on the chairs so the middle of the frame is suspended above the ground. Have a friend hold one end of the frame to keep it from tipping over.

Climb inside the frame and straddle the three center pipes in the cockpit area.

Slowly place more of your body weight onto the frame until your feet are suspended above the ground. If you hear creaking, cracking, or if the frame is deforming significantly, then stop. If the frame doesn’t do any of those things, it’s strong enough to keep you afloat on the water!

If you need to strengthen the frame, attach 10' pieces of pipe along each of the struts. Place the pipe on the inside of the frame and wrap T-Rex tape in many places. You could also slide 1/4" (.64 cm) steel rods inside the struts, however these may be expensive and difficult to locate.

Step 13: Frame Reference Video

This is a short video that shows the complete frame. Reference this if any of the illustrated diagrams are not clear enough.

Step 14: Cut and Attach the Waterproof Layer

WATERPROOF LAYER

1. (Picture 1) To prevent leaks in the skin of your kayak, first cover the frame with plastic sheeting: Spread out a 10' x 10' (3 x 3 m) sheet of plastic and lay the frame on top. Fold the plastic up along each side of the frame and use scissors to roughly cut off the excess. Temporarily tape the plastic in place at each connector.

2. (Picture 2) Now refine the fit of the plastic sheeting: Starting at one end of the frame, undo one piece of tape holding the sheeting in place. Pull the sheeting taut. Cut off the excess so the sheeting reaches just over the top strut. Tape it into place.

Repeat at every connector. Evaluate the sheeting for severe wrinkles and smooth them out by undoing, tightening, and reattaching. Small wrinkles are fine. They won’t be noticeable once the kayak is covered in tape.

Trim the sheeting along the bow and stern so that it overlaps by about 1" (2.5cm).

Step 15: Create the Duct Tape Skin

Time to tape! The plastic sheeting will rip and tear easily. Covering it with a layer of duct tape will greatly increase the durability of your kayak.

3. (Picture 1) Flip the kayak over and apply a single length of T-Rex tape along the bow, the bottom, and stern edges of the kayak.

PRO TIP: Each time you apply a long strip of tape, smooth and press it into place with a dry cloth. This will press out air bubbles and ensure that the maximum amount of adhesive comes into contact with the plastic sheeting.

4. (Picture 2) Working from the stern of the kayak toward the bow, and working on one side at a time, apply the next long length of tape. Overlap the previous piece of tape by half, and unroll the tape 12" to 18" ((30.5 to 45.7 cm) at a time. Press the tape down and smooth it out as you go.

5. (Picture 3) Continue applying tape along the length of the kayak. You’ll need to overlap the tape more at the bow of the kayak than at the stern.

Flip the kayak upright and continue applying tape until you reach the top strut. Repeat on the other side.

Step 16: Finish Duct Taping

7. (Picture 1) Cover the bow and stern edges with several layers of tape to cover the loose tape ends, and reinforce the seams.

8. (Picture 2) The corners of the 45° elbows put extra strain on the plastic sheeting and tape. Reinforce these corners to prevent tearing. Apply at least two layers of tape along each section as shown. Tape the top edge of the sheeting to the top strut.

Note: Although one layer of T-Rex Tape is sufficient, I strongly recommend adding a second layer to prevent against tears and leaks. Two layers is the minimum amount of reinforcement tape you should use. I recommend a third. For the top layer you can use a less expensive tape.

Step 17: Skin the Deck

10. (Picture 1) Create the deck: Cut a piece of plastic sheeting that fits over the top of the kayak at the bow end as shown. Temporarily tape the sheeting in place. Then fit it, as in step 2, alternating between pulling the sheet taut, trimming it with scissors, and applying a small piece of tape to keep it in place.

11. (Picture 2) At the high point, at the center of the cockpit edge, cut the plastic along the mid line and overlap the edges as shown to take out excess wrinkling. Tape the cut edges.

(Picture 3) Apply a single long piece of tape that pulls the sheeting taut and attaches it to the cockpit edge.

Step 18: Duct Tape the Deck

13. (Picture 1) Apply at least two layers of tape very tightly over the high point, above the cross beam. You can use regular quality tape for the deck. Next apply another two layers of tape that reach from the underside of the cross beam to the tip of the frame. The tape will be more taut than the sheeting. Press the tape onto the sheeting to lift it up. These lengths of tape will help the sheeting keep its shape as you cover it with tape, and will ensure that it retains the graceful curve that will prevent water from pooling on the deck.

14. (Picture 2) Lay overlapping pieces of tape along the sheeting toward the bow of the kayak. Next apply horizontal strips of tape to the sheeting that’s facing the cockpit. Avoid wrapping tape from the underside of the cross beam toward the tip of the kayak. This may cause the plastic to lose tension and create pockets for water to pool in. Repeat steps 10 through 14 at the stern of the kayak.

Step 19: Get Paddlin'!

The kayak is complete!

For a cockpit seat, tape a folding stadium seat to the kayak frame, or build your own out of PVC, foam, and tape. Decorate it with colored tape or permanent marker decals. Create waterproof pockets for storing your phone, or build elastic tie-downs for holding you bag securely as you paddle.

Safety First: Kayak in Calm Waters Only

Although this kayak is 100% functional, it’s not guaranteed to keep you safe in rapid or turbulent water. Use this kayak in still waters only, and inspect it thoroughly before and after each use for damage. Bring along a dry cloth and extra tape in case you need to make field repairs.

Additionally, be sure to learn how to use a kayak before your maiden voyage. Kayaks are not the easiest watercraft to handle, and may feel a bit unstable on the water until you’ve had some time to practice.