Undetectable leak

I’m looking for some advice regarding putting epoxy over a painted fibreglass canoe. The issue I’m having is with an undetectable leak. I’ve repaired the cracks I can find, but it’s still leaking. By the end of an hour of paddling, I have a small puddle under my seat (I’m the heaviest in the canoe).
Can I just epoxy the whole thing? Can I do that without putting down more fibreglass? Any suggestions would be fantastic!

This isn’t really an answer to your question… Have you considered putting water on the inside while on land and checking for a water trail on the outside?

Epoxy doesn’t stick to paint like you want.

Carefully get in off of a dock where everything stays completely dry inside. Unroll some toilet paper, and it will reveal the source of the tiniest leaks. A paper towel will work pretty well also.

Dustin: I’m planning on doing exactly that this weekend, thanks for the advice!
Cape fear: I don’t understand. I put the canoe in the water, remove it before water leaks in, then run toilet paper inside the canoe?

Hope you find the leak!

I can’t reply for CapeFear, but I think he was saying look for the leak while the boat is in the water. Lay some toilet paper or paper towels in the boat and look for where it starts to get wet.

1 Like

Exactly. By “where everything stays completely dry inside”, I simply meant that if you can get into a completely dry canoe without water dripping in off of paddles and legs and feet, then you know that little water the paper is soaking up is from a leak. Should be quite easy to trace to the source.

Is the “leak” water after an hour from the hull or paddle drippings?

How did you repair the cracks you found?

Capefear: Perfect, thank you for the suggestion!
Overstreet: I don’t think it’s from paddles, no one seems to be dripping. I think it’s from the hull.
pblanc: I used a fiberglass sheet with resin.

What type of resin did you use? Do you know what resin was used for the canoe construction?

You said the canoe was painted. Did you paint it or do you know that someone else did? Or are you referring to the color coat which is almost certainly polyester gel coat.

Either way, when you applied your fiberglass patch did you first thoroughly remove the colored material and sand down the entire area of the patch till you saw fibers of the structural fabric of the canoe? If not, you may not have gotten a good bond.

pblanc: I used this - Bondo Fiberglass Resin Repair Kit, 420, 1/2 Pint - 420C. No idea what resin was used in construction, my dad picked it up from the scouts camp in Haliburton when they were getting rid of them. The more I work with it, and the more I fix, I’m thinking it’s actually Kevlar. Not 100% sure at this point.
The fixes I did were on the inside ribbing… turned out to not be structural, or cracked through the hull. Nothing I can see seems to be cracked through the hull, but that’s probably because it’s painted on the exterior.
The boat was painted before I got it (by my dad), I have a feeling I’m going to need to sand the whole exterior before this is sorted.

No Kevlar there, that’s for sure. Bondo is a polyester resin. And the fabric is no doubt some type of E fiberglass. Bondo and other polyester resins will work IF polyester resin is what was used to construct the canoe but polyester will not bond well to a boat made with vinyl-ester resin or epoxy resin. If it is a cheaper canoe there is a fairly good chance that is was built with polyester but I would try to find out from the manufacturer.

If you have water leaking into the hull you have a through and through crack somewhere and it only takes a pinhole. Sometimes water will percolate in through and exterior crack and enter the canoe through and interior crack some little distance away from the exterior point of entry.

With a crack that results in a leak I would always try to apply an exterior patch over the point of entry first.

1 Like

Well… Three points. They all seem to be along the keel, but I’m worried it’s just collecting there… No obvious other areas where it’s leaking.

I always end up with water in my canoes, to some extent. Mostly from a dripping paddle…
I like using a grouting sponge to remove any water. Cheap, light and easy to pack.

Is it enough to justify a bunch of epoxy?