C-Forum

I wish I new about this sight before I tried outfitting my tripping canoe a couple of years ago. I used Vynabond to glue some tie down points and had no problems. But, in my hurry to get on the river, I glued on a couple of kneepads with Vynabond and did not let it dry. Needless to say, you know the result. I have two huge dents on the outside of my boat. It appears that the inner core melted and the royalex layers are now welded together. I've been told by the manufacturer (Nova Craft) that the strength has not been compromised, but boy is it ugly and no longer streamlined. Does anyone have a suggestion on how to fill these dents in? Anything would look better than how it does now.

PC-7
Bondo
Resin with a filler
ABS putty (search this forum)

Top with one of the new plastic spray paints (i.e. Krylon Fusion) for UV protection and appearance.

That's a tough one. The best resins, such as West G-flex, may be costly because of the size of the dents. Try pouring water out of a measuring cup into the dents to give us an idea of the volume.

If cost were no object, I would probably mix microballoons with G-flex (for lightness) and build up each dent by stages, before sanding to true contour. Then you could paint like Broam said.

Remember not to do too large a volume of an epoxy repair all at once. The stuff gets hot when it cures.

I have also used 3M Structural Adhesive for outside Royalex repairs. I suppose it could be mixed with microballoons for lightness.

Contact Raka epoxy if you go the epoxy route. Their product is very good and the prices are excellent. They carry various mixes of epoxies including custom blends if you ask, various fillers including micro-balloons and an assortment of cloths.

You don't have to fill the voids with expensive epoxy either, you can rough up the area, build up JB Weld if it's not a high flex area, sand to smooth and *then* coat with glass or synthetic cloth and good epoxy. I made my bow repairs/bang plates this way and they've held up perfectly through repeated thwackings. I've repaired various small dings around the hull with *only* JB Weld and haven't had a single fill or patch pop out. I think the key is to get the area immaculately clean and to rough it up with course sandpaper. Also, if you play with the hardener/filler ratio, you can get it to cure with a bit of flexibility. "Industro-Weld" (or whatever they call it) is just normal JB Weld in giant tubes, by the way.

Phreon

Thank you, everyone, for responding. Because of the location of the dents, it's near impossible to pour something in them to measure the volume. They are both on the rounded part of the boat, where the side and the bottom meet. These are not actually from the knee pad installation. I took my time with them. The dents occurred when I hurried the installation of the wedges near the sides and applied weights so the minicell would conform to the curve. All I can say is, I can lay my hand in them and my hand is a bit thicker than the dents. Maybe 15 fl. oz. or so, each. Not sure if it's a high flex area or not. I do take this boat on week long river trips, so it's loaded down and there's always the possibility of hitting something.

Thanks again for your help.

Dean

Nova Craft may be right in saying that the strength is not compromised.....much. You might wear out the rest of the boat before you chance to put enough stress on these areas to make a difference. But because these areas are ALREADY compound-convex curved, they are not going to respond to being bent inward.

Phreon's advice about JB Weld and then some glass and epoxy over it is inexpensive and probably pretty strong. I would replace the JB Weld with G-flex and microballoons, followed by a layer or two of S-glass. But my approach isn't cheap. And you might be advised to build up the G-flex and microballoons in two layers in order to avoid the tendency of epoxy to get hot when it sets in a mass rather than a thin layer.

I don't use JB Weld, but 3M Structural Adhesive might be an alternative. It would probably take you two batches of it to fill the depressions. It is somewhat flexible and fairly light.

What about West Systems other products?

I've used West 105/205 resin for a number of projects. It is stiffer and harder than G-flex, though G-flex, once it has set up, is not rubbery. G-flex, for your application, would have better flexibility, possibly better adhesion, and because it sets slower, it might be less likely to set "hot" in a deep hollow like you are filling. But as I think about it, JB Weld or 3M Structural might be very good alternatives. The JB Weld would certainly be cheaper.