Royalex repair

WHat’s the best way to repair a 2 inch gouge in a royalex canoe? Is plastic welding an option on Royalex?

JB Weld

Works great. Is slippery too.

epoxy and fiberglass patch bond well?

When you say 2" gouge, do you mean
there is a deep dent 2" long but the outer layers are not cut or pierced? Or do you mean there is a 2" gouge that goes into the pale green ABS or even into the foam center layer?

The stuff can’t be welded. Gouges can be filled with a 2 part structural polyurethane like some made by 3M (someone else will be presenile enough to remember the product number), or the gouge could be leveled by mixing West G-flex with a filler like microballoons.

Once leveled, the filler can be smoothed and painted. If the canoe is to be used in whitewater, I would use a low angle chisel to skim off the vinyl around the gouge, and then apply 2 concentric layers of glass, using epoxy resin, to strengthen the damaged laminate. Not necessary if the laminate was not pierced.

3M Scotch Weld
2 part urethane adhesive 3532.

Works pretty well for straightforward repairs of gouges, small holes, etc.

Seems to stand up to the sun, too.
I have a 3M repair of a long, narrow gouge on my Synergy, and I think it’s lasted through a dozen years of sun.

It is
a 1-2" hairline “cut” all the way through. Can see daylight through the hole. Wenonah Adironadak 16’. The damage is in the side/curved area of the hull.

Forget what I said about JB Weld

Sounds like maybe S glass or kevlar time. I’ll shut up and listen and let the more experienced help you make it right.

I have used G-Flex to repair “cold cracks” near the gunwale line that are full-thickness. To do this you are going to need to make the crack bigger, however. You need to enlarge the gap enough to let the epoxy into the center, and G-Flex is about the consistency of honey at room temperature.

You will probably need to use a thin file to gutter out the crack. If you can’t get a thin file in, you may need to drill through the crack with a drill bit large enough so that you can get a thin file in. Drill several holes right next to each other through the crack.

You should also round off the edges of the crack somewhat. G-Flex comes with repair suggestions and instructions that outline this. West Systems (maker of G-Flex) also recommends briefly flaming the surface with a propane torch, but they say this is optional for Royalex. Position the canoe on its side, or partially on its side so that the G-Flex flows into and fills the crack with gravity assistance. Use some tape (clear packing tape or Duct tape works) on the inside of the hull to contain the G-Flex.

The G-Flex alone may give sufficient strength but G-Flex can also be used with fiberglass or Kevlar cloth for a stronger repair. But using cloth will result in a more obvious repair as well.

FG sandwich
Here are some cracks the Chipewyan developed.


  1. sand down the area on both inside and outside the hull. The pictured hull crack picture was taken after sanding with the sandpaper-flap wheel. ABS is the lighter colored surface around the crack. The tan is vinyl.
  2. Tape the hole shut and fill it with something. Epoxy, thichened and mixed with FG shreds is a good choice. Let it dry, then resand if necessary
  3. Remove tape
  4. Practice good hygene. First was the area with soap n water, then rub down with alcohol.
  5. Cut 6 patches of FG material

    2 Patches 2" wider than the hole

    2 patches 1" wider than the first patch

    2 patches 2" wider than the first patch
  6. Lay up the FG patches smallest to the largest on each side of the hull
  7. Sand and paint.

    My patch is going on 3 years and 30 days of paddling. I used regular west system epoxy, not gflex, which is probably better. Heat it to make it flow into the material.



All good except I would lay the largest
patch first on each side, and so on down to the smallest. This is recommended both in Walbridge’s Boatbuilders Manual and on the West Epoxy site for repair of FG boats. Hiding the smaller patches under the larger leaves small discontinuities. With the smaller patches on top, you can feather their edges with sandpaper.

If pblanc’s G-flex procedure is done on the Royalex first, one might get away with a two layer Kevlar patch inside and a two layer FG patch outside. Patches should be oval in shape to reduce transition zones in stiffness.