Royalex repair. Skid plates or epoxy?

I came into a possession of a well worn Royalex Mohawk Challenger this past summer. Now that my paddling season has a fork in it, I plan on peeling off the duct tape and fixing some old damage. I though I’d run my plans past you fine folks here at Paddling.Net first.

Both the bow and stern have significant wear, with the stern showing all the way through to the core in a small (dime sized) spot. I estimate the area on each end where the actual ABS needs shoring up (rather than just the vinyl) is about the size of a slice of bologna. I also planned on filling in a few small dings after sanding them well.

I’m not sure my style of canoing necessitates skid plates and plan on carefully building the areas up with J.B. Weld (recommended by Mohawk). From experience, I know J.B.Weld is very tough and figured I’d resort to skid plates if a year or two of paddling results in significant re-wear.

Assuming I follow general Royalex repair tips such as cleaning the work area with alcohol, roughing up the surface to be epoxied, etc., do my plans seem sound? Is there a significant performance difference between purpose Royalex repair epoxy and plain old J.B. Weld? Any other tips/tricks of the trade?



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Ad-Hoc ABS paste?
I found a thread on that advocated making an ABS repair paste by disolving chunks of ABS pipe in acetone. Have any of you tried this?


don’t fit skid
plates if you don’t need them and if you can do the repair without them. I found they slow down the hull somewhat and if you’re really going to hit something hard, the boat is less flexible-leaves the paddler as the weakest link on impact.

As for JD: it is not as flexible as some other epoxy.

And I don’t fill small dents if they have no hard chines: you can heat them up carefully with a heat gun (no flame!) and they’ll come back out.

I use diluted acetone for cleaning the RX hulls-works better than alcohol-just don’t spill the undiluted stuff on your boat.

won’t work
as ABS and Royalex are not the same…

RX is PVC and is affected by acetone.

ABS is not (really). If you disolve PVC shavings in acetone, the paste won’t cure te way you want.

I could imagine, disolving PVC in Vinabond or H55. The paste would probably be to soft for hull repairs, though. Could be worth a try for filling dents (those that can’t be done with heat), though.

Isn’t royalex vinyl coated ABS?

– Last Updated: Dec-20-06 3:51 PM EST –

I was under the impression that Royalex is a foam core, ABS sheet, vinyl coated laminate. Am I mistaken?

I'm more concerned about repairing/protecting the ABS than the vinyl.


A few are small punctures

– Last Updated: Dec-20-06 3:56 PM EST –

A few are classic small triangular punctures that may or may not have broken open to the core. I figured I'd fill those for good measure (there are only a few) and ignore or heat the dents as you suggested (of which there are many).

I guess my real question is, "What cheap/effective patch material do you suggest"? J.B. Weld, Royelex repair epoxy or other? Can I feather the epoxy out from the stem/keel repair to cover the surrounding hull wear or will it flake off if applied too thin?



Yep Phreon:
Royalex is a foam ABS core sandwhiched between two or more (at reinforcement & wear points)pieces of vinyl.

I have used PC-7 epoxy putty for small repairs such as blisters. Still going strong.


not going to
give you any advice as EVERY rivertripper I paddle with has kevlar plates on their canoe, except my son who seems to find a better line than mine or anyone elses. Just want to let you know that the Mohawk Challenger is one awesome river tripper. My mentor has one with a saddle and that is one great tight, rocky, river trippin’ canoe.

but still: acetone doesn’t disolve ABS.

Might destroy it, though.

I don’t know
I read that thread on cboats and more than one person has melted ABS pipe in acetone and then applied it in thin layers to the exposed ABS on their royalex. They did it to repair large areas where the ABS was worn through to the foam.

Sorry, but I can’t look for the thread right now.

I would use S-glass or E-glass and
West epoxy to reinforce the areas. I would NOT use Kevlar felt skid plates because they are thick and heavy, but not that strong.

I personally use a cabinet scraper to remove the vinyl over-layer before putting on at least a 3-layer, concentric, largest piece first, glass patch. You can use Kevlar fabric, but it will fuzz as it wears, and Kevlar is not as strong as S-glass for external patches.

I second the West Epoxy
with some glass for the repair. BUT if you plan to do any paddling that will have the boat coming in contact with a rocky bottom, you may want to consider adding a top layer of sacrificial material such as some kevlar. I just helped do some repairs on a boat that was going down to do the lower canyons of the Rio Grande and the rough bottom just about removed all of our repairs in fairly short order. A few thin strips of skid plate material would probably have done a good job of protecting the repair.

I’d just use epoxy resin
I was thinking on adding skidplates myself, but didn’t really think I needed the weight of kevlar. I decided to just mask off the area like I was installing skidplates and just used epoxy resin with no cloth. The epoxy I used is EA 9309, I know it’s a Mil Spec resin, but hey, I work on aircraft. Figured if it can withstand mach speeds then what’s a few rocks going to do to it. So far it’s been great and held up real well. No chips in it but a few scratches, nothing a can of Dollar General red can’t hide,

JB or epoxy
will work well for filling in gouges or covering areas where you’ve worn through the vinyl.

Unless you’ve got a crack (which can propogate and grow) there’s usually no need for fiberglass or kevlar cloth.

My WW boats take alot of abuse. Anytime a spot starts to wear through the vinyl, I just smear a thin layer of JB over it. The JB lasts me for years, even with heavy use.

I have had success patching deep
scratches, those going through the vinyl and exposing the ABS, with 3M Structural Adhesive. I have not tried painting anything over broader areas of exposure except glass and epoxy. Glass cloth and epoxy don’t add much more weight than epoxy alone, unless one is covering a big area, when the weight of the glass becomes a factor. I wish that carbon cloth had better ability to stand up to wear, because its lightness is sure great.

I took another look
I went down to the basement last night and took another look at the hull. The area that truely needs to be built up is pretty small, the rest is just surface abrasion. I think J.B. Weld/Marine putty will do ok.

Can epoxy putty be worked in layers? Will it stick to itself without sanding?

I was also thinking about using thin ABS sheeting as a simple skidplate.



JB is good for me also
I just saw a Marine Expoxy at Walmart by Loctite. Any one knows about how good that one is? As for JB, it sure does the job for me.

Some epoxies develop an amine
blush that must be washed off the surface before putting on another layer. This is true of West epoxy. And, once you’ve washed off the blush, you might as well sand a bit and wash again.

If you thicken West epoxy with colloidal silica, you may be able to get by with a single layer. Otherwise you should use a thicker substance. The 3M Structural Adhesive is nice and thick.

West is best for laying up cloth where its good wetting properties come into play.

You remove vinyl over-layer?
I got a wildfire that is in need of repair. The inner core is visible at the bow and close to it at the stern. The vinyl is worn away making the core visible in an area about an inch wide and maybe 4-5inches long. Had a lot fo fun and many miles wearing the ends down but now it is time to stop the damage from spreading.

Sounds like the s-glass would work geat but should I remove more vinyl before making the repair? I guess I am wondering about how much vinyl you would remove before epoxying the glass patch. Does the expoxy adhere to the core better than the vinyl?

Never had a royalex canoe before and dont have a clue. Any pictures that might help?

I think I’ve settled on…
… J.B. Weld as a filler (going to remove a bit of core, it feels soft in a spot) and West Systems epoxy plus 10 oz. glass cloth in leiu of kevlar mat. Pretty much exactly what Mohawk recommends.

Now to figure out how much epoxy/hardener I need.