Royalex scratch and dent repair

I have been restoring canoes of various brands and materials for a number of years. I know there are many who balk at the time and effort and overall purpose in attempting to restore an old royalex hull full of scratches and dings. Regardless, i just wanted to offer my experience in this area. My latest project is a 30 yr old Mad River Explorer which had completely rotten gunwales and a blackish dirt film that took major effort with a Scotch Brite pad to remove. The hull was in fairly good shape but 30 yrs of useage were showing in the royalex. With a heat gun, carefully going along each deep scratch in about 12 inch lengths, i would heat up the area for about 10 seconds then using the heal of my hand over a cotten cloth, i would press down using significant force along the length of the scratch/gouge in a back and forth motion and the heated vinyl would very often reseal itself and smooth out very nicely. This is more than just cosmetic because the cuts in the vinyl will/have exposed the core material which is bad if exposed to the elements. It is amazing at the results you can achieve if done carefully. The main precaution is to avoid overheating and avoid performing this on full penetration cuts in the vinyl layer at the outside curves or chines.The natural desire for the vinyl layer will be to stretch open the gap and expose the inner core much more. In other words, only perform this heat method on flat or relatively flat surfaces. As far as deep puncture type gouges and dings, I would heat them gently and then pound the heal of my hand in the area with a couple layers of cotton insulation and the surface becomes remarkably smooth. BTW this obviously works best if you are not having to pay for the electric bill where the heat gun is being used.

Good work, but I wonder what is inside
the Royalex, both before and after the heat gun and massage routine. I’d like to get a Royalex wrecker and use a saw to cut through damaged areas. The question is, does the foam-inter-layer usually adhere to the ABS structural layers, or does it pull loose under damaging force or when the heat gun is used to induce the outer ABS layer to return toward the original hull contour?

Plasticized foam substrate
I believe the inner core thick layer is some type of compressed plasticized foam that when heated at the factory molds, will soften and expand. Thus allows it to be pressed into the hull shape and expand to provide the inherent flotation that makes royalex marginally unsinkable. I am confident the structural integrity of the layers are totally intact.

Interesting post - Thanks
I’ll have to stick this in my memory bank, since we have three royalex canoes.

Jack L

On the boats you’re working on, that
is more likely to be true. On Royalex ww canoes that have been beaten half to death, the overall flex of the hulls is testimony that something may be wrong inside. Until the laminate cracks open, a saw is the only way to know.

Your Royalex procedure…
…seems like a common-sense approach to an almost universally occurring problem. Nice!

What kind of heat gun are you using there?

Heat guns range from hair dryers to roof installation heaters that cost several hundred dollars, run on 220 V and are used to melt the seams together.