Got some dents in a royalex canoe. I was planning on sanding them then filling them in with JB weld. But I read here on Pnet that if you heat the dents with a heat gun they may pop out. Any of you ever tried that?
I used a blow dryer on a whitewater PE boat one time. The dent was about the size of my fist right in the bow. I was amazed at how much the dent came out. I was gradual with the heat trying not to concentrate it in a small area. It took about 30 minutes of heating, gradually working my way around the dent to apply even heat. I would try a blow dryer first. A heat gun may be a little much.
I agree with the previous comment about trying a blow dryer first. If you need to use a heat gun, go easy. REAL easy.
I found out by accident that the heat from a 100-watt bulb at a distance of a couple inches will make Royalex too flexible to even maintain its own shape after just a couple of minutes. You don’t want to heat it enough that THAT happens, so I think very slow heating would be the trick.
I may just stick with JB weld!
I used a heat gun
on a poly boat and it worked well. Just don’t get it so close it burns it. JB weld is good stuff, but I don’t know if it would stick to Royalex very well. Royalex is flexible, JB Weld is not, so it will likely pop out.
I did some checking on it. Royalex is an ABS sandwich, with ABS, rubber, ABS then vinyl. I would try the heat. ABS can be worked around 170 F.
Heat can work OK on a one-sided
groove or dent, but if the distortion goes through both ABS layers, applying heat inside and out will be a challenge. I think if I badly gronked the bow of an ABS boat, I would be tempted to just cut it out and build a new bow out of cloth and epoxy.
watch out for 200 - 220 degrees
I tried to reshape the bottom of a royalex canoe. The melting point of royalex is listed as 220. Up to about 200, not much happened. Around 200 - 210, I was able to change the shape. But the transition from just enough heat to reshape to heat that makes royalex molten happens with frightening speed. I was able to reverse the oil-canning, but a fiberglass patch now covers the spot that got too hot.
Just fill it up with water on a flat surface for 24 hours. It pushes out all dents.
I would thing the shape of the hull would prevent a whitewater boat from sitting flat enough.
JB Weld works well on Royalex. I use it to install PVC tubes for tugeyes. That new Krylon Fusion paint should stick well to cover the patch if you can find a matching color.
Redrocket, you mean HOT water?
Fill the boat with HOT water? That sounds like a project.
But without heat, dents in poly boats usually will not reform just by being pushed back into place.
Maybe you’ve got heavy water in your taps.
Dents in Royalex are often …
...on the outside surface only. I don't think water weight on the inside of the boat would do a thing to fix that kind of dent.
In this case, it seems that the application of heat causes the inner ABS layer to swell, and that combined with the softening of the outer vinyl, pushes out the dent.
The process you describe might work for a dent that goes through the full thickness of the hull if it's on or near the bottom of the boat. I wonder if water straight out of the tap would be hot enough though.
It does not work on cosmetic dents of course, I was referring to when the hull itself has a dent in in where it distorts the actual shape of the hull. I was not clear enough. I have gotten significant dents in my rolalex canoes
From wrapping around trees and rocks, or from laying on my trailer to long. I also meant hose water, it has worked for me personally 4 or 5 times. Good luck! Oh as to a whitewater boat with a rocker this would probably not work unless you had a sand box to lay it in or something along those lines. I hope that clears up my original statement, I was just trying to help. I did it in the middle of summer, that probably helped to.