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Repairing a royalex hull?

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Hello folks! I recently acquired a Wenona Spirit II for an excellent price, which I’m going to try to repair. It’s royalex, from 2007, burgundy in color, has seen a lot of hard use, and been stored in the sun and snow. I’m new to canoe repair (and to fiberglass work), but am generally pretty handy.

Outcomes:

I’m trying to make this boat usable again. I don’t need it to be perfect, but would like it to look decent. I won’t be as hard on it as the teenage boys who used to take it down the Bloodvein, but I also don’t want to have to treat a royalex boat as a trophy piece. I would like to be able to portage with this boat, so weight is another consideration. It will be stored outside in Montana, or at best, in an unheated garage. I don’t mind spending a small amount on materials/tools if it means doing the job correctly. Durable, simple, lightweight, decent looking repairs are my goal.

The problems, my plan, and questions I’m hoping you fine folks have suggestions for:

1) The outer vinyl has worn away in the beam of the boat, along the chine, and the ABS has been left exposed to UV radiation for over 7 years. The ABS in this area has cracked, allowing moisture into the foam. Someone has tried to seal this area using what appears to be a resin, but it has cracked again anyway. From reading other threads here, I’ve concluded that I need to cut away the cracked ABS and sand the edges smooth. I plan to fill the resulting gouges with Gflex epoxy, thickened with silica, and sand it back to the original hull shape. So my question is, do you knowledgeable folks think I need to either a) put fiberglass in the gouges (as is done 7 minutes into this video: youtube.com/watch?v=cTAXGS7xWkU), or b) cover the whole damaged area with fiberglass? I would prefer not to, but obviously also want the boat to be structurally sound. Also, is there any reason to put graphite or pigment into the epoxy I use here?

2) The fiberglass skid plates are both A) worn down, and B) cracking at the edges (especially the bow skid plate). Again, someone appears to have slathered resin over top of this in an attempt to mitigate the damage, and that resin has subsequently cracked as well. Is it worth trying to salvage the existing skid plates (perhaps by injecting G-flex into the deeper/wider cracks and applying it over top of the plates as well? Or would it make more sense to just try to remove them and start over?

3) Other, smaller areas of the bottom of the hull are also worn through to the ABS, but do not seem to have otherwise suffered. Given the extent of this type of damage, I think that once the hull repairs are done (and the skid plates have been removed if applicable), I will paint the bottom of the boat, up to about 3” above the water line, with EZ-poxy, to protect the ABS from further degradation. Does anyone have a sense for how much weight 2 coats of EzPoxy would add to the boat?

4) Along the sides of the boat, above the water line, there are some chunks of vinyl missing (from being transported touching other boats there, or from ice/snow during outdoor storage?). Again, these have been "painted" over with a layer of resin on the starboard side, but not on the port. I plan to sand the resin back, smooth the vinyl-to-abs edges, apply Gflex, sand to smooth, and then spray paint with Krylon Fusion All-In-One. The color won’t match perfectly, but Wenonah tells me they haven’t carried color-matched paint for several years now.

Any thoughts, tricks or insights on this project, tips on materials, etc would be more than welcome! Thanks!!
 

Glenn MacGrady

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Hello folks! I recently acquired a Wenona Spirit II for an excellent price, which I’m going to try to repair.

Laxpuck, welcome to site membership! Feel free to ask any questions and to post messages, photos and videos in our many forums. Please read Welcome to CanoeTripping and Site Rules! Also, please consider adding your location to your profile, which will cause it to show under your avatar, as this is in many ways a geographic sport. We look forward to your participation in our canoe community.

You seem to have read some of our prior threads on Royalex repair and appear to be on the right track. Hopefully some other members will chime in.
 
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You have a real project on your hands. I was given a canoe much like yours and after much consideration did this with it.

Sorry, not much help to you, but I do like the bookshelf. Oh, and my wife makes me keep it in the basement.
 

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Progress so far:

All the brittle, cracking ABS has been cut away, and the resulting gouges sanded smooth. Once the GFlex arrives, I will use hardened GFlex to fill the holes.

Any thoughts on whether it needs fiberglass on the outside to remain structurally sound?
 

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Any thoughts on whether it needs fiberglass on the outside to remain structurally sound?
Yes! I have used s-glass in the past, depending on usage it won't last that long but quick and easy to apply, I think the s-glass was 4oz, it pretty much goes invisible even with a couple of layers.

If looks don't matter at all, I'd patch with dynel which is what I will be doing on my own boats which have far worse hull damage than yours, lots of cracks and a huge area where the vinyl is gone (but no exposed foam core anywhere)
 
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The areas of exposed outer solid layer of ABS (the yellowish areas) are almost certainly thinned out to greater or lesser degree. These areas will be prone to erosion that extends into other areas of the foam core.

If you want to keep this boat a while I would definitely apply a belt of fabric down both chines of the outside hull over these areas. I would use either 6 ounce/square yard, plain weave S fiberglass or 5 ounce/square yard plain weave Dynel. The S fiberglass would impart more structural strength but the Dynel would be somewhat more abrasion-resistant.
 
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Yes! I have used s-glass in the past, depending on usage it won't last that long but quick and easy to apply, I think the s-glass was 4oz, it pretty much goes invisible even with a couple of layers.
I would definitely apply a belt of fabric down both chines of the outside hull over these areas. I would use either 6 ounce/square yard, plain weave S fiberglass or 5 ounce/square yard plain weave Dynel. The S fiberglass would impart more structural strength but the Dynel would be somewhat more abrasion-resistant.

Thanks recped and pblanc! I just ordered some S-glass for it, and some dynel for replacement skid plates. Now I just need to get to work removing the old skid plates, and hope I don't run out of warm weather!
 
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Thanks recped and pblanc! I just ordered some S-glass for it, and some dynel for replacement skid plates. Now I just need to get to work removing the old skid plates, and hope I don't run out of warm weather!
Sometimes those crappy skid plates can be removed more easily than you might think. You can try warming the surface with a heat gun but be careful as over warming can cause the foam core of the Royalex to deform.

Try getting under an edge of the skid plate with a thin blade or putty knife. If you can do that you can sometimes loosen up the bond by twisting the knife a bit. A wood chisel with a fairly narrow blade sometimes works as well. If pieces of the skid plate are left on the boat, you can use a power sander (with care) to get them off.
 
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Make sure to flame treatment and alcohol wipe. Significantly more adhesion.


If you decide on dynel pick up peel ply release fabric and press it flat with hard roller after it sets up a little. Dynel sucks up a lot of resin and swells. There is a good thread on skid plates on this site. I don’t see any reason to add graphite powder except to add color.
If the glass is really necessary wouldn’t it be better inside hull due to higher tension forces inside hull on impact? The thickened gflex and abs should handle the compression on outside reasonably well.
 
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Foxyotter, thanks for your input! Having read those numbers, I'll be sure to flame treat! Should I not sand before applying the G-flex? Or is that article just saying that after sanding, it is important to alcohol wipe as well, before flame treating?

I think that what pblanc and recped are suggesting is to essentially create a thin "skid plate" along the chine of the boat. That way, as it continues to drag over rocks, sand, etc in the future, the area that is already wearing thin will have additional material, and thus hopefully won't wear down to raw ABS all over again. So it will provide some structural reinforcement (which may or may not really be necessary), while also helping reduce further abrasion.
 
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Make sure to flame treatment and alcohol wipe. Significantly more adhesion.


If you decide on dynel pick up peel ply release fabric and press it flat with hard roller after it sets up a little. Dynel sucks up a lot of resin and swells. There is a good thread on skid plates on this site. I don’t see any reason to add graphite powder except to add color.
If the glass is really necessary wouldn’t it be better inside hull due to higher tension forces inside hull on impact? The thickened gflex and abs should handle the compression on outside reasonably well.
If the outer solid lamina of ABS has been abraded right through and into the foam core, as it clearly has in multiple areas in this case, the surrounding exposed ABS has almost certainly been thinned out to the point that it won't take much more abrasion to wear through into the foam core in other areas. Putting cloth on the inside of the hull won't protect against this. Applying a layer of cloth to the outside will protect against this and will serve to replace the structural material that has already abraded away.
 
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Honestly I have no connection to West Systems besides happy customer. Pblanc I assumed the outer compromised areas would be cleaned, sanded, cleaned with alcohol and carefully flamed treated. (See description in above article about flame treating if unsure.) Followed shortly by coating in Gflex and 406 filler then faired smooth but a litte high. Glass on outside would help achieve a consitenant and more durable layer on outside. Glass on outside will add some strength but mostly in compression and I think that the tension forces exerted by an impact which occurs on inside is the weakest link after thick coating of glflex. I would present this article and their menthod for best practice and point out thier reasoning for more layers of glass on inside. Note that article was written before Gflex and states at top, best practice is to use gflex instead of epoxy.


Pblanc and recped I am sure you both have more real world experience with this stuff I am just presenting information sources that lead me to my hypothsis. A little glass and gflex on outside is probably more then suffcient. I am often amazed at capability of Gflex such as this article with only gflex used no glass for cold cracks.

 
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Honestly I have no connection to West Systems besides happy customer. Pblanc I assumed the outer compromised areas would be cleaned, sanded, cleaned with alcohol and carefully flamed treated. (See description in above article about flame treating if unsure.) Followed shortly by coating in Gflex and 406 filler then faired smooth but a litte high. Glass on outside would help achieve a consitenant and more durable layer on outside. Glass on outside will add some strength but mostly in compression and I think that the tension forces exerted by an impact which occurs on inside is the weakest link after thick coating of glflex. I would present this article and their menthod for best practice and point out thier reasoning for more layers of glass on inside. Note that article was written before Gflex and states at top, best practice is to use gflex instead of epoxy.


Pblanc and recped I am sure you both have more real world experience with this stuff I am just presenting information sources that lead me to my hypothsis. A little glass and gflex on outside is probably more then suffcient. I am often amazed at capability of Gflex such as this article with only gflex used no glass for cold cracks.

I have either applied abrasion plates to quite a few (two dozen or more) Royalex canoes that have worn through at the stems or repaired them in other ways, such as mending cold cracks or other cracks, using West Systems G Flex epoxy. I am pretty familiar with West System's recommendations for use and their adhesion data, and I have talked with their customer support people on a number of occasions.
While flame oxidation is absolutely critical for achieving a decent bond with polyethylene, West System actually describes flame oxidation as an "optional" step for bonding to ABS. Also, unless you have removed all of the vinyl layer from the area of Royalex you are applying epoxy to you, are not just bonding to ABS, you are also bonding to PVC. You will note that the improvement in tensile adhesion that is achieved with flame oxidation is very modest when bonding to PVC with G Flex.

You will also note that the tensile adhesion data for ABS shows that flame oxidation after sanding the surface with 80 grit sandpaper yields absolutely no improvement in bond strength compared to sanding with 80 grit paper alone. I have asked the customer support people at West System about this and they had no explanation for it. So if flame oxidation does nothing to improve the bond strength after sanding with 80 grit sandpaper, why in the world would it do so after wiping with alcohol instead? Or does it? You really can't say from West's adhesion data since they didn't do the comparison.

I can tell you from experience that the bond strength of G Flex to Royalex is actually quite good without flame oxidation. I have applied abrasion plates to about two dozen Royalex boats that were part of a livery fleet that were wearing through into the foam core at the stems.
These were not my boats and I was not getting paid so I did not make any attempt to remove all of the vinyl that the abrasion plate was going to cover only if it was loose. I always sanded and then thoroughly cleaned the area including a final wipe down with denatured alcohol. While the West System G Flex adhesion data does show a significant improvement in bond strength to ABS with an alcohol wipe down followed by flame oxidation, they do not present any tensile adhesion data for an alcohol wipe down alone, or an alcohol wipe down following sanding with 80 grit paper. So it is really not possible to say with any certainty that flame oxidation is of any benefit after wiping the surface down with alcohol.

And when I spoke to customer support they told me that had no such data. So we really can't assess how much improvement in bond strength, if any, is achieved by flame oxidation of ABS after either alcohol wipe down alone or alcohol wipe down following sanding. I can tell you that none of the abrasion plates I applied to the canoes I worked on for the conservation society I did volunteer work for have delaminated, to my knowledge.

My current practice when applying a fabric patch or abrasion plate to a Royalex canoe is as follows, and it has yielded very good results.

First, I remove the overlying vinyl layer when practical so as to bond directly to ABS rather than PVC. Sometimes that is easy but sometimes, especially when working on a very concave surface it is not. All surfaces to which epoxy is going to be applied is then sanded and thoroughly washed, then given a couple of wipe downs with denatured alcohol. I will flame oxidize any exposed solid ABS. I do not try to flame oxidize exposed foam core. The little trabeculae of those cells are very thin and easily melted. Plus, the exposed open cells provide outstanding footing for a good mechanical bond. I do not try to flame oxidize vinyl when I am unable to completely remove it from an area to be repaired

You are correct in that the fibers on the outside of a canoe hull tend to be compressed when a convex surface is indented while those on the interior are subjected to tension. But that is no reason not to use fiberglass on the exterior of a canoe hull because fiberglass fiber is actually very strong in compression, much better than aramid. The compression strength of aramid fiber is only about 1/10 of its tensile strength while fiberglass has a compression strength close to that of its tensile strength. What is more, fiberglass binds to epoxy and other resins much more strongly than aramid does so the laminate strength for fiberglass is actually very close to the laminate strength of aramid even in tension. The following webpage compares the properties of aramid, carbon fiber, and E fiberglass. Note that the laminate strength for E fiberglass is as good or better than that for aramid when comparing tensile strength. And that is for E fiberglass. S fiberglass is 20-25% stronger still. And note that the strength for epoxy unsupported by any type of fabric is very poor, so simply replacing lost hull material with epoxy alone is not going to do much to prevent further abrasion of the ABS and erosion into the foam core.

Why use aramid? Simple, it has a higher strength to weight ratio so you can use it to build a lighter (not necessarily stronger) canoe. The weight savings is significant when building a complete hull but not so significant when applying abrasion plates or a couple of patches.

 
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In the name of educating some future clueless newbie like myself, I've put together this progress update. Hopefully someone can learn from my mistakes!

1) I've removed one old skid plate, including sanding down the old resin and paint surrounding it. I used a few chisels, often as levers. As a result, I did a bit of hull damage which I repaired with Gflex 655 (the thick stuff). For newbies like me, I would recommend either using a small pry bar instead, or using a lot more caution than I did. I also found that a grinder was a far better tool than a palm sander for removing the old resin, but both are probably necessary. I'd recommend 80 grit on the grinder and 36 (or 40) for the sander. 36 grit in the grinder required extreme caution, and resulted in a few "oops" moments.
20220922_120028.jpg
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2) Confidence boosted by success with the 655 above, I used it to fill the areas along the chine where I had cut and sanded away the cracked, brittle vinyl and ABS. I then used a rasp, followed by sanding, to return to the hull shape. (Before and after shots below).
20221006_185729.jpg
20221008_221221.jpg

3) It was then time to apply a layer of fiberglass, to help prevent the same darn problem from popping up all over again. And I will say up front that I was totally new to using fiberglass or similar laminates, and that I did...okay...at best. I followed the advice in all the excellent discussions of skid plates on this site. I used 4oz S-glass and it elongated and narrowed a LOT more than I had anticipated, even cut on a bias. This is probably in part because I was using narrow, long pieces (nearly 70" long, and only about 8" wide). But in any event, I had to cut a new piece of fiberglass halfway through the job because I had ruined one, and I found myself trimming the glass as I was laying it down, to keep it within my tape job.

Once the drips stopped running, I pulled the tape, and applied peelply. My application of epoxy had been...uneven, and the peelply allowed me to fix that a little bit, but less than I had hoped. I tried using a cheap wallpaper roller to smooth things out, and it promptly broke. A flexible plastic spreader was a decent replacement. Applying and pushing down the peel ply also ruined my nice clean epoxy lines. I tried doing one continuous piece on one side, and three overlapped pieces on the other. One continuous piece worked better, even if it was harder to apply. I left it overnight, and when I pulled it, I noticed that each of the places where it had been folded for shipping left a defect in the epoxy. Nonetheless, the fiberglass was applied. Huzzah!
20221025_145827.jpg
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4) So I had the fiberglass applied, but some areas clearly had not had enough epoxy, and others had too much. So I sanded things down to a more even, but far from perfect surface (palm sander, 80 grit). I also hand-sanded the edges to smooth them to the hull a bit. Then taped and papered again, and applied a really thin layer of epoxy to smooth out all the imperfections from my glass layer. I applied it with a foam brush (which I highly recommend), and used a flexible plastic spreader (Bondo sells a useful 3-pack) to smooth and remove any excess, which worked really well. It is still curing, but I think this part went pretty well.

Moving forward, I'm still planning to remove another old skid plate, put dynel skid plates on the bow and stern, and paint the hull, at least below the waterline. But I've run out of decent weather, so most of that will have to be next spring.

So a big thank you to all the folks on here who gave me advice, and who wrote treatises on royalex repair, skid plates, etc. You all rock!
 

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Glenn MacGrady

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You've done a lot of learning and made a lot of progress, laxpuck. Thanks for documenting both your successes and struggles so well with pictures and descriptions, so that others in the future can benefit from your experience.
 
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You've done a lot of learning and made a lot of progress, laxpuck. Thanks for documenting both your successes and struggles so well with pictures and descriptions, so that others in the future can benefit from your experience.
Thanks Glenn. I tried to make a video, but...it turns out that pictures are more my speed. 🙂
 
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In the name of educating some future clueless newbie like myself, I've put together this progress update. Hopefully someone can learn from my mistakes!

1) I've removed one old skid plate, including sanding down the old resin and paint surrounding it. I used a few chisels, often as levers. As a result, I did a bit of hull damage which I repaired with Gflex 655 (the thick stuff). For newbies like me, I would recommend either using a small pry bar instead, or using a lot more caution than I did. I also found that a grinder was a far better tool than a palm sander for removing the old resin, but both are probably necessary. I'd recommend 80 grit on the grinder and 36 (or 40) for the sander. 36 grit in the grinder required extreme caution, and resulted in a few "oops" moments.
View attachment 133076
View attachment 133077
View attachment 133078

2) Confidence boosted by success with the 655 above, I used it to fill the areas along the chine where I had cut and sanded away the cracked, brittle vinyl and ABS. I then used a rasp, followed by sanding, to return to the hull shape. (Before and after shots below).
View attachment 133069
View attachment 133070

3) It was then time to apply a layer of fiberglass, to help prevent the same darn problem from popping up all over again. And I will say up front that I was totally new to using fiberglass or similar laminates, and that I did...okay...at best. I followed the advice in all the excellent discussions of skid plates on this site. I used 4oz S-glass and it elongated and narrowed a LOT more than I had anticipated, even cut on a bias. This is probably in part because I was using narrow, long pieces (nearly 70" long, and only about 8" wide). But in any event, I had to cut a new piece of fiberglass halfway through the job because I had ruined one, and I found myself trimming the glass as I was laying it down, to keep it within my tape job.

Once the drips stopped running, I pulled the tape, and applied peelply. My application of epoxy had been...uneven, and the peelply allowed me to fix that a little bit, but less than I had hoped. I tried using a cheap wallpaper roller to smooth things out, and it promptly broke. A flexible plastic spreader was a decent replacement. Applying and pushing down the peel ply also ruined my nice clean epoxy lines. I tried doing one continuous piece on one side, and three overlapped pieces on the other. One continuous piece worked better, even if it was harder to apply. I left it overnight, and when I pulled it, I noticed that each of the places where it had been folded for shipping left a defect in the epoxy. Nonetheless, the fiberglass was applied. Huzzah!
View attachment 133072
View attachment 133073
View attachment 133074

4) So I had the fiberglass applied, but some areas clearly had not had enough epoxy, and others had too much. So I sanded things down to a more even, but far from perfect surface (palm sander, 80 grit). I also hand-sanded the edges to smooth them to the hull a bit. Then taped and papered again, and applied a really thin layer of epoxy to smooth out all the imperfections from my glass layer. I applied it with a foam brush (which I highly recommend), and used a flexible plastic spreader (Bondo sells a useful 3-pack) to smooth and remove any excess, which worked really well. It is still curing, but I think this part went pretty well.

Moving forward, I'm still planning to remove another old skid plate, put dynel skid plates on the bow and stern, and paint the hull, at least below the waterline. But I've run out of decent weather, so most of that will have to be next spring.

So a big thank you to all the folks on here who gave me advice, and who wrote treatises on royalex repair, skid plates, etc. You all rock!
A patch of any plain weave fabric, in which the individual fibers are woven but not bound to each other in any way, will tend to elongate lengthwise and narrow transversely as you wet it out. This is like the old "Chinese finger cuffs" you may have played with as a kid. This is true of fiberglass, Dynel, and aramid. I always mask around where I intend to apply the patch, leaving the tape about 3 mm or so of where I want the patch to be. This will help you avoid the "shape shifting" as you wet the patch out. You will usually need to work the fabric transversely as you do so to maintain the proper shape, but that is not too hard. Start wetting out at the center of the patch, and work toward the edges, being quite gentle as you wet out the very edge.

Peel-ply will allow you to achieve a more uniform epoxy application at the cost of using a bit more epoxy. I apply the peel-ply after I feel I have adequately wetted-out the fabric, but it is often necessary to apply a little more epoxy over the peel-ply itself. You don't want any dry spots on the peel-ply. I have found that plastic squeege tools of the type used to apply auto body filler work best for this. Work any excess epoxy out from the center of the patch toward the edges, allowing the excess to sit on your tape mask. Obviously, this must be done before the epoxy kicks too hard.

It is almost always necessary to apply at least a second coat of epoxy to the fabric to achieve a completely smooth surface. This can be done as soon as the initial application of epoxy has cured to a green state. The fibers will take up some of the resin after you wet the fabric out and they will swell a bit as they do so. This is especially true for Dynel. If you try to fill the weave of the fabric all in one shot you will inevitably wind up applying too much epoxy and getting sags and runs.
 
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