Introduction

Rotationally molded kayaks, like the garbage cans that are also made this way, tend to get brittle and crack after being left in the sun too long. Sharp curves may split.

Two common sticky substances from the hardware store can make a permanent repair.

"Great Stuff" is rigid foam in a can.  It will expand and cause distortion of closed spaces as it expands, but, given one wide-open surface, it will cure to  form a fairly rigid mass.  It adheres to almost anything that is clean and roughened to help it grip.
  • "Great Stuff" is rigid foam in a can. It will expand and cause distortion of closed spaces as it expands, but, given one wide-open surface, it will cure to form a fairly rigid mass. It adheres to almost anything that is clean and roughened to help it grip.

  • "Through The Roof" is a petroleum-solvent based product made for patching roofs. Sticks to anything, even tar on the roof. Fumes are terrible. Work in an area with good ventilation. It resembles "Shoe Goo", but costs a lot less per oz and dispenses easily from a caulking gun. A gooey liquid at first, it then gets rubbery, finally gets tough.

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Scrub near the split with coarse sandpaper to give the foam better adhesion.  Use a stick to reach deep into the kayak if necessary. Use ropes and straps to bend the kayak back into shape and force the edges of the split together.  Maybe use a correctly shaped form on the outside under the ropes/straps if it distorts.  Use plastic sheeting under the ropes and straps along the split to keep any foam that leaks out through the crack from adhering to the ropes or straps.
  • Scrub near the split with coarse sandpaper to give the foam better adhesion. Use a stick to reach deep into the kayak if necessary.

  • Use ropes and straps to bend the kayak back into shape and force the edges of the split together. Maybe use a correctly shaped form on the outside under the ropes/straps if it distorts. Use plastic sheeting under the ropes and straps along the split to keep any foam that leaks out through the crack from adhering to the ropes or straps.

  • Prop the boat up so the Great Stuff will fall from the can's spout onto the part inside the hull where you want it to go. Do this in a location where you can leave the boat for a few days to be sure the foam has a chance to fully cure.

  • Empty one or more cans of Great Stuff ($3 each on sale at Ace) into the boat. One picture shows the location of this particular repair (port side, behind the seat), the other shows what the foam looks like after it solidified. Yes, it's ugly. But if you try to smooth out the foam before it sets up it collapses the foam and it is still ugly.

  • After a few days, put the boat back down on the ground and take off the ropes and straps. The foam will hold the split together. The can says that the foam should be painted, but years of experience suggests painting is unnecessary.

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Deck the Halls
With tools and Fix Kits
The amount of foam pictured was the contents of two cans. Don't worry if  small gaps remain as the unexpanded foam "plops" into the cavity.  As it expands, the foam will fill in and "rise" on the open side.
  • The amount of foam pictured was the contents of two cans. Don't worry if small gaps remain as the unexpanded foam "plops" into the cavity. As it expands, the foam will fill in and "rise" on the open side.

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File down the edges of the split to make a place to fill with "Through The Roof", lay the boat on its side so the goo won't run off, then apply "Through The Roof"  along the crack.
  • File down the edges of the split to make a place to fill with "Through The Roof", lay the boat on its side so the goo won't run off, then apply "Through The Roof" along the crack.

  • A few days to let it cure some more and it's done.

  • Shipshape? Pretty much.

  • Bristol Fashion? Fugetaboutit!!

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Conclusion

Avoid getting the sticky stuff in the eyes!!!!!

"Fair winds and following seas!"

3 other people completed this guide.

RDB

Member since: 10/30/2014

169 Reputation

2 Guides authored

3 Comments

There is actually a product for repairing these correctly. Expandable foam is just a more horrible repair later. Take a look at Gougeon Bros WEST System G/Flex epoxy, found here:

http://www.westsystem.com/ss/gluing-plas...

https://www.youtube.com/watch?v=2a5RlcP-...

Marcus Ward - Reply

The G/Flex Epoxy is impressive, although I'm not sure how well it would work on brittle plastic. In my experience, sun-weakened plastic that falls apart by on its own holds together when bonded to foam. With G/Flex alone, my kayak would shatter if dropped on its "sunburned" side.

Also, G/Flex is expensive. The kayak in the video looks to me like it has $50-worth of the stuff on it. The kayak repair I did cost $5 for foam and about $1 worth of a $12 tube of roof goo, the rest of which I used on a roof. For a new boat, G/Flex would be worth it. My boat was a basket case I rescued from a dumpster.

RDB - Reply

Just no just !&&* no just buy a used kayak or fiberglass it that wont last 2 yeArs tops

karsonking91 - Reply

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