How to Repair a Polyethylene Kayak
Kayaks built from polyethylene are tough and resilient, but with wear and tear can become deeply scratched and even cracked. Submerged objects, concrete docks and boat launches all take their toll on the kayak's plastic surface. Even cuts and cracks above the waterline can compromise the boat's strength, and scratches beneath the water slow performance. With a propane torch and polyethylene welding rods, you can easily repair cracks and deep scratches and restore the boat's integrity.
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Things You'll Need
- Propane torch with heat nozzle
- Plastic polyethylene welding rods
- Lint-free rag
- Alcohol
- Sandpaper
- Rasp or Surform
- Flat-tipped screwdriver
- Wire cutters
- Gloves
Instructions
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1
Place the kayak in a warm, well-ventilated area out of direct sun, making sure that you can easily access the area you're repairing and that the boat is stable.
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2
Clean the repair area with alcohol or window cleaner and a lint-free rag, and allow to dry. Sand the area lightly to aid the bond, and then clean it again.
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3
Light the propane torch and heat a welding rod tip until it starts to bend and melt. Place the rod end 1/4-inch to 1/2-inch before the crack, keeping the torch nozzle pointing at the rod tip. Heat both the rod and the boat surface, tilting the rod away from the torch.
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4
Push the rod through the crack, applying heat so the rod and the boat surface melt together. A small bead of melted plastic will run ahead of the rod tip as you push. Continue to push the bead until it is 1/2-inch past the crack's end, then remove the heat.
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Snip off the remaining rod with wire cutters and, using your gloved finger, smooth the heated plastic evenly into the crack.
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6
Allow the repair to cool completely. Test the weld with a flat-head screwdriver by trying to pull the welded area loose. If the weld breaks free, re-sand and clean the area and start again.
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7
Use a rasp or Surform to clean and flatten any rough edges around the repair, and then smooth with sandpaper.
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Tips & Warnings
Practice welding polyethylene first by welding two rods together or melting a rod onto a hatch cutout or an old boat top.
Use a propane torch and a metal spoon to fix small scratches. Heat the spoon tip and rub it along the boat to smooth the surface.
If the boat surface begins to melt and bend excessively, remove heat immediately. Allow the surface to cool, and try again. Heat the rod more than the boat for safe welding.
Boats with excessive UV damage from sunlight will have faded and become brittle, and you may not be able to repair them. To be safe, recycle the old boat and get a new one.
