Canoe Has cracks, but doesn't leak? Suggesitons

Advice
#1

Hello. First time poster, thanks for all of you who have contributed. Great site here.

The short story (to the point)- The exterior hull of my old town canoe has massive cracks in it in multiple locations. I’ve used it like this for 2+ years, and it never leaks.

  1. how is this possible . 2) repair ideas on a budget?

long story-
2 years ago I bought a VERY used old town discovery 169 for very short money. My boys and I (total weight for the 3 of us 370lbs) use it on day trips, mostly fishing, in calm locations only. no rapids.

It looks horrific, we’d like to paint it and add a center seat for my youngest son, 70 lbs, who currently sits below or on the center thwart.

Aside from the scratches and completely faded blue, the bottom of the hull is, as a friend and fellow canoer calls it, “mangled”. It has multple cracks, several of which are up to a foot long and emanating from a protruding outward bulge.

Upon purchasing it, we tested it in a shallow pond for fun, figuring it’d leak. It didnt. We’ve taken it out on prgressively longer and more distant trips, and the thing never leaks. How is this possible?

Is this a 2 layer hull? If so, we are probably getting water between the 2 layers? Perhaps this is why its so heavy, but it rides fine in the water, and doesnt seem to ‘draft’ especially low even with 3 of us and a backpack.

I’d like to repair this and repaint, but honestly do not have (nor want) to make a substantial investment in doing so. The buyer used duct tape or gorilla tape, which I promptly I replaced, but now its all gone and yet, still doesnt leak and seems to ride “fine”.

If I can figure out how to post pics I will. Its baffling to me that this thing still floats.

Suggestions on a repair this large apprecaited at both the “on a budget, one step better than duct tape for a pond floater” as well as “on a budget but do it right”.

Additionally, seeking to add a center seat.

THANK YOU for any help, and thanks for a great site.

#2

Discovery is the cross-link hull with several layers. Find a good material to repair the cracks on the polyethylene skin. Then sand it lightly and paint. it.

#3

It is a three layer roto-molded polyethylene hull. Powdered PE is added sequentially in three steps into a mold that shakes and vibrates inside an oven. The PE powder melts and is distributed across the interior of the mold. The second “dump” of PE powder has properties that cause it to expand and form a foam core that provides buoyancy and thickness (for stiffness) without adding as much weight as solid PE. The first and third dumps of PE powder are such that they form solid layers on the outside and inside of the hull.

Your problem is that as a polyolefin polyethylene is quite chemically-inert. It isn’t quite as bad in that regard as polypropylene but most adhesives will not bond well to it. West Systems G Flex epoxy will bond tolerably well to PE but only if you pretreat the surface you are bonding to to make the PE less chemically-inert through an oxidative process. Industry often uses chemical oxidation for this purpose but that is not practical for home canoe repair. You can however oxidize the surface temporarily by passing the flame of a propane torch quickly over the surface then applying your epoxy within 30 minutes. You can fill the exterior cracks with G Flex in this way and the cured epoxy can be sanded fair and smooth if need be.

You can buy enough G Flex to fill the cracks for about $25 or so. Google “G Flex 650” to find on-line retailers. You will need an inexpensive hand-held propane torch as well. The instructions with the G Flex will tell you exactly how to do the flame oxidation. After the epoxy is fully cured and smoothed paint over it with some color of paint that reasonably matches the color of the hull.

If this sounds too difficult or expensive go back to Gorilla tape.

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#4

Fast response!

Thanks for the info and feedback.

Does the inner foam core absorb water? Being PE I am assuming that it is non absorbent.

Looking into the GFlex repair kits. I took some pictures too, will post tomorrow.

#5

The cellular structure of the core is pretty much closed but it will take in a little bit of water. Also the solid outer layer of PE sometimes has a tendency to delaminate from the core material allowing the entry of water between the outer and the core layers to the extent of delamination.

If the cracks have exposed the core material you should be able to tell. The “Swiss cheese” appearance of the core material is very characteristic. If you have exposed core I would use denatured alcohol to get any water out before repairing it. You may need to apply alcohol repeatedly. EtOH and water are miscible liquids and the alcohol will get rid of any water.

If you have exposed core you can fill in the exposed cells with G Flex epoxy. You should still flame oxidize the area but go very quickly and carefully over any exposed core as the thin walls melt quickly.

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