Major Royalex repair?

Hello, first time poster, long time paddler.

I’ve been paddling mostly solo a Penobscot 17 in some downriver WW races and Class II-III with some occasional IV drops (often not successfully). I have been looking for a shorter solo for river running and to make the WW more enjoyable. I just acquired a used '88 Mad River ME. It’s just the kind of canoe I had been looking for and I was very excited to find it. I was leary of the condition of the royalex. The owner said it was mostly stored inside but some summers (whatever that means)it was stored under a shade tree by the water. I looked at the hull pretty carefully and didn’t see any signs of obvious delamination or fatigue. The worst the hull had were some minor gouges and the usual scratches:

Anyway, I bought it happily. It is otherwise in very good shape and came with some servicable air bags and knee pads. I have subsequently built my own pedestal, redone the lines, varnished the thwarts and carry handles, and moved the center thwart. So, I took it for my maiden voyage on my local Class 2-3+ run that was raging from recent storms. Everything was going great until I hit this:

Now the side of my new boat looks like this:

So, after my initial heartache, I’ve thought about repairing it. I’ve read a lot here and elsewhere and it seems like a several layers of s-glass or kevlar fabric using GFlex insides, plus maybe another one or two layers outside could fix this. However, then I started worrying that the royalex might be compromised on this old boat and it might not be wortht it. This was the first impact I gave the boat, but to be fair, it was a very big impact that sent me swimming. I’m not sure my much newer Penobscot would have faired any better. So, before I spend a lot of $ and time fixing this I want some advice whether it’s worth repairing it. I’d hate to have this happen again next time I hit something in the river.

If I should repair it, my questions are these:

  1. Kevlar or S-glass?
  2. How many layers inside and how many outside?
  3. Should I cut away all the broken royalex and tape some cardboard over the outside of the hole (with wax paper) and begin the repair from the inside, OR should I straight all that broken stuff out and tape it temporarily to be part of the repair?
  4. For a hole this large, how far beyond the cracks should I extend the patch.

    If the answer turns out that I should plant peonies in it, please help me find a similar boat. You would really make a downtrodden paddler feel better. I’m in Maine, for what it’s worth.

    thanks for the help!

Others will offer opinions, but mine is

– Last Updated: Oct-21-12 11:05 PM EST –

that it appears to be a brittle fracture associated with old Royalex.

What someone might do is post a picture of a Royalex boat that was wrapped when it was no more than fiver years old.

When a relatively new Royalex boat pitons hard into a rock, the bow will crumple in relatively smooth folds. I saw a 20+ year old Royalex boat hit an obstacle at high speed, and what resulted was a jagged split.

If we conclude that the canoe under present discussion has gotten brittle, then we'll know that it can't be used in whitewater. It might be repaired and used for lake duty, though the repair may add enough weight to be felt.

Let's leave the repair cloth issue aside until we know what sort of goal we're setting.

P.S. "Yankee" might mean that you are in Bew England. Kaz of might have knowledge about the boat's repairability, and might repair it for a reasonable amount, if you and he agree on the money and effort.

Picture close-up
Here are a couple close-ups of the break and layers:

I usually don’t chime into the repair questions here too much (I do canoe/kayak/SUP repair for a living), but felt I need to add my two cents.

I fear for the overall integrity of the Royalex. She looks awfully brittle and my gut tells me if you repair these wounds, you will encounter the same type of damage when next you bang around in the river. The tough thing about Royalex is that you can ALMOST NEVER tell from looking at the hull how good the sheet is. Some sheet will never cold crack, some will, some sheet will get brittle (like yours), some never will, etc. When you hit that rock that caused this damage, the hull should have not reacted like it did. If I did the repair, it would cost $340+. For me, the only stuff I use is a Plexus product (MA550) which costs a lot of $$$$$$. There is NO guarantee that the rest of the hull won’t react the same way when it gets hit. This canoe should be left to a life of fast water, easy rapids, or a flower bed.

Sorry, but I feel your safety is more important that hoping that the canoe will survive the next hit. Email me if you want to discuss this further.


Sadness abounds
My heart broke when I saw those pics. What a shame. I love my ME. If it isnt salvageable, I would be interested in your endcaps.

My condolences once more. Glad you are ok and able to share the tale however.

25 years ago people said Royalex tears couldn’t be repaired. But there was a guy named Jim Booker, who was a professional welder in the Amherst, MA, area, who had figured out how to weld Royalex rips and tears. He repaired my ME that way – though the tear was not as bad and multi-directional as yours. He claimed the weld was stronger than the original material, and I never had any reason to doubt that.

Booker used to paddle with the Berkshire Chapter of the Appalachian Mountain Club.

Even if he’s not available any more, surely there are other welders who have figured out the process for Royalex.

My method…
makes for an indestructible repair. My concern is for the rest of the hull. I believe the Royalex itself has become brittle and will continue to “fall apart” against the rocks.

MR Courier
If that were mine I would be off to the dump with it, no trust in that hull. I agree with Rob and he knows what he is talking about.

I do know someone in VT who has a MR Courier for sale for around 300$ if you are interested in that hull. I have one and love the way it handles. Shoot me an email if you are interested and I can contact the owner.


Time to move on? What boat?
Is there any test I can give it to see if the hull has any quality left? Someone on NPMB suggested taking a bat to it. I tried the blunt end of my splitting maul (because I don’t have a bat) but I couldn’t bring myself to really wail on it. Anyway, in my medium hits it bounced the way it should. I also tried flexing the hull all over and i didn’t hear any cracking. I also took it to the Old Town factory and had one knowledgeable guy look at it and he thought it was probably okay. A friendly engineer at Mad River took a look at the pictures above (including the close-ups) and thought it was probably not worth risking it.

So, I’m conflicted. If there is a good way to really test the integrity, I’ll consider repairing it, otherwise I’m leaning towards ditching it and looking for another boat.

I blew my play money for a boat between the boat itself and a bunch of outfitting supplies (which of course can transfer to a new hull) so I don’t have lots of money for a new boat. In the 4 miles of Class II-III I paddled this boat I really liked it. Is it time to ask for suggestions for similar hulls that are newer and can be found relatively inexpensively?

Thanks for the suggestion about the MR Courier, DougD. The price is right but based on the specs I found I think it’s somewhere between my Penobscot and the ME. I think I’m looking for a more playful boat, but one that can still track reasonably well on flatwater stretches. I’m pretty sure I want something in the 14-15 ft. range (i.e., not a more modern stubby WW boat). I see a fair amount of Mohawk XL-15’s come up for sale but everything I read says they are great beginner boats, which usually means they get boring quickly.


I would probably fix it

– Last Updated: Oct-23-12 4:41 PM EST –

but I share the same concerns about the ABS being brittle that others have, and would be reluctant to use it on whitewater.

I would use G Flex epoxy rather than a methyl-methacrylate like Plexus simply because it is much cheaper. It bonds to ABS well. Mixed with a thickening agent like colloidal silica, it can be used to fill voids and fair uneven surfaces on the hull. It also wets out fiberglass and aramid cloth well.

I would try to fit the pieces of broken Royalex together like a jig saw puzzle. Try to secure a stiff piece of cardboard covered with Saran Wrap to the outside of the broken hull to maintain shape. Clear plastic packing tape can also be used to hold the approximated pieces together. Thicken the epoxy with colloidal silica to bond the broken pieces together from the inside and use multiple applications to fair the broken hull surface. G Flex can be mixed up in very small batches and sands well when cured.

When you get the interior as smooth as possible do the same thing on the hull exterior and fair it as best you can. I would apply a single large sheet of aramid to the inside of the hull extending at least 2" beyond all broken edges. You might want to use peel ply over the aramid to get a smoother edge. On the outside I would use a single layer of S 'glass again extending at least 2" beyond the breaks, but try not to have the edges of the fiberglass line up with those of the aramid.

You could use more layers, but I suspect this repair would be as strong or stronger than the remainder of the hull. If you wanted you could cut strips of S 'glass to bond over the joined breaks and feather the edges of those strips before covering the whole with a large sheet of S 'glass.

Feather the edges of the S 'glass well and fill the weave with enough applications of epoxy. Paint it over with red Krylon Fusion spray paint, and if desired, you can spray over the aramid with some flat grey spray paint as well.

You can buy a 32 ounce kit of G Flex epoxy from Sweet Composites for $56 and I think it would be enough to do the repair:

Three ounces of aerosil (colloidal silica) will set you back another $4. A piece of 5 ounce per yard aramid 36" x 58" would cost another $27:
and a piece of 6 oz/yd S 'glass 36" x 60" would be another $19.50:

A 36" x 64" piece of nylon fabric (peel ply) would cost $9.50:

So far you are up to $116 less shipping. Adding costs for incidental supplies like disposable gloves, sandpaper, tape, spray paint and shipping costs will put you around $150 or so. To me that would beat taking the boat to the landfill.


– Last Updated: Oct-23-12 10:48 AM EST –

I suspect Royalex is prone to these types of puncture holes. I repaired one once that had a softball size puncture. A white pine tree limb fell vertically and punched right through the canoe.

I glued the remaining Royalex puzzle pieces back together with G-flex. I filled any remaining missing puzzle piece areas with thickened G-flex,and then patched the inside with fiberglass and patched the outside with fiberglass. I filled the fiberglass weave with G-flex, sanded and painted with Krylon to protect the epoxy.

As far as I know, the repair has held up fine, but the family uses the canoe for flatwater trips pretty much exclusively.

The hole was smaller than yours and not on the turn of the bilge, which may complicate things.

Good luck.

okay, thinking about fixing it
Thanks for all the advice. I’m leaning towards fixing it and seeing how it goes. My questions now are:

  1. I have pushed the pieces back into their original plane and there actually aren’t any missing pieces. I understand that normally for a crack, you would bevel the edges of each side of the crack so that the epoxy adheres not just to the outer layer of the hull but also to some of the interior of the royalex. However, if I put a large patch of kevlar and/or s-glass over this whole area, it would extend beyond any of the cracks and be adhering only to the outer surface of the hull. Is roughing it up with sandpaper enough or do I want to get the outer surface (inside the hull or outside) off entirely on the outer edges of the patch?
  2. Back to the question about whether the hull should have done this in the first place. I feel fairly confident that this was really a puncture from the blunt end of the tree (not a rock), rather than just a bashing like would happen if I hit a rock broadside. Do you folks think royalex still should not have punctured if it weren’t old and brittle?

    Thank you, all.

maybe a freak accident
but many of us have hit logs hard with Royalex boats and not experienced such extensive fractures. Obviously, the only way to find out is to repair the boat and start paddling it.

For bonding linear cracks it is definitely best to “gutter out” the crack using something like an old “church key” can opener as a scraper. In that event you are trying to maximize the bonding surface of the epoxy and diffuse the stress riser that occurs at the interface between the epoxy and the ABS. In your case, the cracks extend obliquely through the entire foam core and both solid ABS strata. My feeling is that beveling the cracks at the surface probably wouldn’t gain you much, but you could certainly do it.

I would probably just clean the foam core well using denatured or isopropyl alcohol and allow it to dry well. Don’t use acetone or MEK as it will dissolve the foam core. I would coat the exposed foam core with a coat of epoxy applied with an “acid brush” just before mating the surfaces and then use clear plastic packing tape to keep the surfaces aligned on the side of the hull you are not working on. If you use G Flex you have a working time of 45 minutes or so at normal temperatures. If the shape of the canoe does not look fair, you may need to use a sheet of thin plastic or stiff cardboard on the outside of the hull to maintain shape. I have sometimes been successful holding a stiffener in place against the hull with cam straps, but it depends on the curvature of the hull.

G2d who posts on this forum quite a bit feels it is important to remove the vinyl layer from the Royalex before bonding cloth to it and does so with a sharp chisel. His theory is that the bond of the vinyl to the ABS layer of Royalex is weaker than the bond of epoxy and cloth to the exposed ABS would be. I understand the reasoning, but I don’t do that. I have seen quite a few fiberglass patches applied by others to Royalex boats delaminate, but I have never seen them take the vinyl off the Royalex when they do so. So I just rough up the Royalex surface with something like 80 grit paper and clean it well before bonding cloth to it. You can use acetone or MEK over the solid part of the ABS as a cleaning agent if the exposure is brief, because it doesn’t soak in as it would in the foam core.

After bonding and fairing the hull inside and out with thickened epoxy, I would probably take the time to reinforce over the cracks with strips of cloth about 2-3 inches wide. If you are using fiberglass, you can feather the edges nicely by sanding. Aramid (Kevlar) does not sand well as it fuzzes up, but if you use peel ply over the cloth when wetting it out and remove it when the epoxy is still green, you will get a nice smooth edge. If you do this, try to cut your strips on the bias at whatever angle is necessary so that the fibers in the strips will cross the fibers of your large patches at around a 45 degree angle as that will maximize strength.

After reinforcing the joined pieces with cloth strips, it should be a pretty straight forward matter to apply your large patches inside and out. That will give you a two layer repair over the joined cracks inside and out.

Obviously, you could use E-glass instead of S-glass to save a few bucks, and you could use fiberglass instead of aramid on the inside to save a few more. In my view, your time is going to be the biggest investment in the repair, so I would pay a few bucks more and use the stronger materials. You would not need to completely fill the weave of the aramid cloth on the inside of you didn’t want to. You would want to do so on the outside before painting so as to get a nice smooth surface.

Don’t use aramid on the outside of the hull as it fuzzes up when abraded.

If it were not old and brittle, it might
have punctured, but the puncture would have a different appearance. Proper ABS/Royalex behavior is to show a more plastic puncture. It’s a bit like comparing how a bullet breaks glass, and how it breaks metal.

It may be no coincidence that yours is an old ME, and the one that showed brittle shattering on the upper Conasauga was an old ME. Apparently neither had experienced a tear or puncture before. There may have been a batch of Royalex blanks used to make MEs back then, that had more than usual susceptibility to becoming brittle with age.

I don’t have wide experience with plastics, nor with Mrs. Robinson either, but one plastic I worked with for years was definitely ductile when new, and grew brittle with age. I could restore ductility by heating and allowing slow cooling, which is annealing. Sorry I don’t know how to anneal an entire canoe.

You should also check the foam between the ABS layers, and see if it has become stiff and crusty. Originally it is hard but somewhat ductile. One guy who used to post all the time on pnet was Eric Nyre. He claimed that exposure to water or moisture would eventually make the foam layer stiff, and weaker.

E-glass is OK, if you get into it. Kevlar inside, usually, and glass outside. Review West’s technical writing on repair of fiberglass. But you don’t need to dish out Royalex very much for repairs. Patches: largest go on first, and so on down to smallest.

Found something
Slow day at work, found this site while tooling around the interwebs.

Maybe its useful for you?

Jim Booker weld job - nice find
That’s the welder I mentioned in my previous post, who fixed my ME.

If you read the text, Booker has welded back together a Royalex canoe that arrived in three separate pieces.

I know nothing about welding, but I believe Booker uses sticks of ABS to do the welds.

Here is a source for that page

This web site has a lot of information regarding repair of polyethylene and Royalex or Royalite boats. Not all of the links work.

Jim Booker’s work is discussed. Links are also given to use of cloth and G Flex for repairs, as well as the ABS/Acetone “paint” method that some have had good luck with (my results were pretty marginal).

Quite a few folks have successfully repaired cracked polyethylene canoes and kayaks using inexpensive thermal welders or even by simply melting PE sticks into cracks with a propane torch. To my knowledge, very few have attempted weld repairs of foam-cored polyethylene or Royalex boats.

Years ago, I was half-owner of a battered Blue Hole Sunburst II canoe previously owned by Carrie Ashton. Someone had “welded” an ABS plate to the bottom of that boat to repair a hole under the pedestal. It looked as if a piece of ABS cutting board had been used, and it certainly didn’t look very elegant, but it apparently had been durable. I have no idea what method was used to bond the ABS material to the Royalex or who did it.

If you read through the material regarding the Royalex welding method that Booker used you will find that it involved some pretty expensive stuff. Wasn’t a problem for him, since he was a welder by trade. But the average individual who attempts this is probably looking at some significant up-front expenses (although a cheap welding unit sold by Harbor Freight was mentioned that was judged to “probably work”) as well as a learn as you go experience. Unless, of course, you are fortunate enough to find someone experienced in Royalex welding repair that already has the equipment. Forget about Jim Booker though, as he doesn’t do it any more.


– Last Updated: Oct-31-12 7:55 PM EST –

Thanks for all the tips and war stories, folks.

After getting lots of good points of view from both the "repair it" and "it's toast" camps I've decided to give the repair a go. I did take some good whacks on the hull with a sledge hammer, which bounced off each time (thankfully!). I've decided it's worth repairing it and seeing what happens.

So far, I've beveled (using a dremel grinder and random orbit sander with 80-grit)the edges of the cut and put the first layer of epoxy on the inside to stabilize the hole. I peeled the wax paper off the first side after one day so I could add a second layer of GFlex to a few areas that didn't get enough the first time. I left the wax paper on the outside while I was doing the second coat. When I went to peel the wax off from the outside, much of was stuck to the epoxy that seeped through the cracks. I have had good luck peeling the wax paper away from GFlex in the past (and during this repair from the inside). I'm not sure what happened this time. I guess I'll have to sand it off because if I use a chisel, I'm afraid I'll take off to much of the GFlex that is doing what it's supposed to do.

Anyway, the repair is pretty solid so far. Now I plan to use more GFlex on the outside of the hull all along the crack to finish stabilizing the hull in preparation for the patches. I've ordered kevlar and s-glass material for the inside and outside patches, respectively.

I'll post more pictures once I do the patches. In the meantime, here are a few of the crack stabilizing GFlex process:

More tips are still welcome!

just sand it off
Use sandpaper to take off the wax paper residue. You want to sand it down flush to the hull anyway so your cloth lies down across the joints as cleanly as possible. If you have any cracks visible from the outside that are not completely filled with epoxy, support the hull on its side so that these are facing skyward and fill them in with small amounts of G Flex, using a thickening agent if you have one. Cured G Flex sands quite nicely.

In future, I think you would have better luck using clear plastic packing tape over the joints. G Flex sticks to it less and it you press it down well, it doesn’t allow nearly as much epoxy to seep out under it.

Take the S off of https
and we won’t have to cut and paste it into a browser. Just a hint as I having been following the links.