Repairing Royalex?

Looking for info on repairing the exterior surface of a canoe which shows a little foam. Does MAS epoxy stick to it?

Epoxy or Goop
I’ve used both epoxy and plumpers goop. So far, both are holding up fine. For touch ups, I currently am just using goop, followed by a bit of spray paint. Quick and easy.

conventional epoxy will work
Conventional epoxy like MAS will bond to ABS. I prefer to use WEST System G Flex because it can be mixed up in relatively small volumes 1:1 by eye so there is no waste, but if MAS is what you have I would use it.

Some people have reported good results filling in and over eroded Royalex foam core with Gorilla Glue.

Personally, when I have an area of wear severe enough to have eroded into the foam core, I like to reconstruct the outer solid stratum with a couple of layers of fiberglass which will be stronger than just lathering on a relatively thick layer of epoxy without any cloth.

J. B. Weld is another option
I think J.B. Weld is just another brand of epoxy, though possibly a harder material when cured (I’m not sure). I suspect something a little more flexible might be better (would that include G-Flex?), but I got the recommendation for using J.B. Weld from Mohawk’s website, and have used it several times (I’ll admit that I’ve even filled some scratches that were “borderline” as far as really being in need of attention). The scratches I’ve filled that way have “stayed fixed” for years now.

Thanks just the info I needed!

I have used epoxy, JB weld, and legos. Yep you can put some color matched legos in a sealed jar, put in some acetone, let it set for a day or so and the legos melt into a liquid that you can brush on. Adjust acetone for consistency. Makes for a good durable coating. Manly use this on my WW boats where I’m not too particular on the looks. But have also poured it into deep gashes.

You might mention that it works when
applied to exposed ABS, but painting it over the vinyl top layer doesn’t achieve anything. Also, the coats must be thin, and the solvent allowed to dry or evaporate. If acetone is given a chance, it will soak through the outer ABS, the foam, and the inner ABS, and make a scrambled soft mess of all layers. Happened to me, when an acetone can slow-leaked onto the hull.

use the gorilla glue
as a barrier between the abs core and acetone in the slurry…it’ll look like a volcano erupting as it cures…but you have sandpaper, right?!

Royalex repair
Since the outer layer is vinyl,I have used vinyl repair glue in a tube. This was on gouges,not wear through areas,but I think it would work there.


JB Weld…
is as tough as anything out there for small dings, but if you have to cover a patch much more than an inch or two wide, it’s way too brittle and will crack. All the readily available epoxies I’ve tried are not completely permanent, but plastic epoxy works better for larger patches. There are two epoxies sold in the big box stores that are supposed to be flexible for plastic. One is amber-clear, the other more milky looking. The clear works far better.

Yes, I used it for gouges only
Also, I seem to remember that the Mohawk site recommended J.B. Weld for gouges and dings, but probably not for larger wear areas.

elastic epoxy
G Flex has a significantly lower modulus of elasticity (meaning it is more elastic when cured) than most other epoxies, another reason to use it for Royalex repairs.

It also wets out cloth fine. I have been reluctant to use JB Weld, Gorilla Glue, Plumbers Goop, Sikaflex, Plexus and various other “goops” and adhesives even on small areas of erosion, because with further damage to the area of repair (which is nearly inevitable) at some point a repair with epoxy and cloth will be necessary, and I just don’t know if epoxy will bond well to some of this stuff.

Vynabond and similar vinyl glues are not
gap fillers, but it sounds like you have found some that are. I would think the old products for coating tool handles in vinyl might be good for gaps.

I’ve used 3M Structural Two-Part Adhesive for some deep scratches on vinyl hulls, and it has lasted a long, long time without any apparent UV damage. But that 3M product is expensive. If one looks for a urethane gap filler, I would avoid bubble-up products like Gorilla Glue. (Unless you can get the special Mountain Gorilla Glue.) I believe Aquaseal it a urethane, and it does not bubble. However, it could be a bit harder and less flexy for filling hull surface gaps.

There’s always spruce gum…

The vinyl repair stuff I used was in a little toothpast tube and the consistency of thick honey.I propped up the boat as level as I could. It wouldn’t stay put on a vertical surface for sure. I just figured that adhesion to slippery royalex might be an issue with other glues-evidently not.


3M Scotchweld 3532
I used to use the 3532 2 part urethane adhesive to repair damaged areas, including through and through holes, in Royalex boats as well. It certainly works and is still available.

It is expensive (much more so now than then) and it does not sand well when cured, however. It is also very stiff when cured. It was popular for bonding in D rings mounted on plastic bases which were very popular once. I heard quite a few people complain that the adhesive holding the D ring bases to Royalex hull bottoms was so stiff that it created stress risers at the edges of the plates leading to hull cracks, although this never happened to me.

It never occurred to me to use vinyl adhesive, although I have used it for many other things. Of course, once there is enough wear to expose the foam core of Royalex, the vinyl layer is long, long gone.

epoxy over JB Weld is rock solid
JB Weld is epoxy based. More epoxy on top adheres well, but I usually rough it up a little for good measure.

That is good to know. Although I have not used it, JB Weld has been a very popular repair material for Royalex boats. I have encountered quite a few used boats on which it has been applied.