Thermoform Repair, Carbonlite Repair

Here’s a fracture from this kayak being pinned against a piling with a lot of water pushing against it. No one was hurt and this kayak will be as good as new in one hour.


Here is a detailed step by step photo tutorial on how to repair thermo-formed kayaks. This repair was completed in less than 1 hour with materials easily available at any local hardware or big box store.

Here’s what you will need:

1. Devcon Plastic Welder
This adhesive is very similar to that used to build Eddyline kayaks. It is readily available at most local hardware and big box stores in the adhesives section.


2. Fiberglass Cloth
2-3″ wide fiberglass cloth can be purchased from most marine hardware and auto parts stores. The material sold in Eddyline’s online store is especially nice because the sides of the cloth are closed with stitching and won’t fray.


3. Cardboard Working Surface

4. Squeegee or Spreader to Spread Adhesive

5. (Optional) Hobby Pigment
Used for coloring Devcon Plastic Welder adhesive for highly visible repair areas (i.e., exterior). Krylon Fusion Acrylic Spray Paint can also be used by spraying a small amount into the glue while it is being mixed.

hobby pigment

6. Rubbing Compound for Final Sanding
400, 800 and 1200 Wet sandpaper for finishing.

rubbing compound

7. Masking Tape and appropriate Personal Protective Equipment (gloves, etc.)
Keeps it all clean and your work within the “lines”



Clean repair area of kayak with isopropyl or rubbing alcohol. Mask the repair area. Apply Devcon Plastic Welder on one side of the fiberglass tape and use a squeege to spread evenly over the entire cloth. Pick up this strip and apply wet side down to the inside of the damaged surface.

Wait a minute and then add and spread Devcon Plastic Welder to the exposed “dry side” of the fiberglass tape. Repeat the same process for a second patch, covering the first patch.

The inside repair is finished and you can remove the tape.

Move to the outside of the repair and use a Dremel or similar tool to create a groove where the fracture was. This will receive pigmented Devcon Plastic Welder for the exterior cosmetic repair.

After filling the groove with pigmented Devcon Plastic Welder, you can use a razor blade to take down the extra adhesive before it gets hard. Otherwise, wet sand the finished repair until smooth, then polish.

Finished Thermoform Repair

Back to the Water!

For Those Who May Need More Detail:

I use the above repair materials for repairing Royalex Canoes and even Composite (Glass, Kevlar and Carbon) Kayaks and Canoes. The reason I prefer the method and materials described above is that the materials store easily in the field and mixing the adhesive is a cinch. Using conventional polyester resins and hardeners like MEK (a known carcinogen) in the field is not only hard to mix correctly but also more cumbersome to carry and store after use. Devcon Plastic Welder is really an amazing adhesive that cures to handling strength in 20 minutes. In the repair above we use Devcon Plastic Welder as the “resin” to laminate glass to the inside of the kayak. We also use Devcon plastic welder mixed with a small amount of hobby pigment to match the color to the outside of the boat. This step is not necessary in the field.

The repair materials pictured and used above are small enough to even fit in my PFD as a field repair kit.

You can also just use Devcon Plastic Welder as a filler for scratches and gouges:

  • First lightly sand or Dremel the gouge to be filled. Then clean the area with rubbing alcohol.
  • Squeeze a little Devcon Plastic Welder on to a working surface and add a little pigment to color match the color of the boat surface. Acrylic Hobby Pigment works fine but I prefer Krylon Fusion Spray Paint because it is easier to find around town. I’ll just give a little spray to the Devcon Plastic Welder as I’m mixing the two parts together.
  • This colored Devcon Plastic Welder is great for filling gouges and scratches. I have even used it to rebuild the ends of the boat if you have a very well used boat.
  • Once you have filled the gouge you are working on you can use a razor blade to scrape off the excess.
  • Then you can used wet/dry sandpaper to smooth the surface
  • If you are really a polisher, you can use a rubbing compound to give it the final shine

How Tough Is Carbonlite?

Carbonlite is harder than gel coat (composite kayaks). Carbonlite boats will not scratch or gouge as easily as a Fiberglass boat. I think that Carbonlite does even better on glancing impact than a fiberglass boat that can get spider fractures. Loaded Impact and Torsional Flex is more debatable and probably unique to the individual injury. In a rough surf zone crash you might end up doing repairs on both glass and carbonlite. Different types of repair…and in my opinion a glass boat is more difficult because spidering gel cracks are a real pain.