Calling all royalex crack experts, some repair process questions

Good Morning, and although i’ve never posted here, I’ve spent a fair amount of time researching topics on your forums so thank you for the resource.

to summarize, I have a soft spot in my heart for things that need fixing and a hard time saying no, which is a bad combo when a persons in the market for an used canoe. those character flaws have lead me to bringing home a 16’ royalex penobscot with a crack in a similar spot to a cold crack but it looks like the bow replacement seat was cut too long and was wedged against the royalex. the crack is on the outside and doesn’t go all the way through like the pictures i’ve seen of cold cracks.

i’m hoping to have a few questions answered by the members here with experience in this area:

-i’ve got gflex on the way and i’ve started to channel a v in the vinyl and I’m wondering if you all would attempt gflex only, or gflex and fiberglass on the exterior, or gflex the exterior crack and put some gflex soaked fiberglass on the inside? i see products like gator patches…would some gflex and a gator patch over top once dry be something to consider?

-most of the royalex repairs i see posted are cracked all the way through; in the event of a crack not going all way through will a v-channel on the exterior suffice?

-i will be soloing this boat 99% of the time from the bow seat backwards. i’m a little concerned having the seat back in that area after i cut it to the right length. should i consider flipping the seats? I know that will entail drilling new holes and possibility swapping a thwart but would that make sense to keep the stresses of where the seated boater is going to be out of the repair area? perhaps the location of the crack up by the railings means the repair would be supported better than i think it would?

thanks for any advice

You really don’t know if the crack extends all the way through the ABS layers of the Royalex unless and until you remove some of the interior vinyl layer. The PVC of the vinyl layer is more elastic than ABS and will often stretch without fracturing while the ABS breaks, but the crack in the interior ABS is masked by the apparently intact vinyl.

thank you for the quick reply and you sir are one of the experts i was hoping would offer their advice.

ok, that makes sense. so if it is determined the crack doesn’t go all the way through but a person has opened up the vinyl on the interior does the exterior v channel suffice or at that point would be it better to make the crack wider with a hacksaw EDIT: blade and create the hourglass bevel for more to surface for the gflex to adhere to?

thanks again

The vinyl layer is thin. What you want to be beveling into is the ABS. If you see no evidence of a crack in the interior solid ABS lamina after you unroof the vinyl, I would then start beveling into the cracked solid outer ABS lamina. As you do so you will hopefully be able to determine whether the crack extends into the ABS foam core (it usually does). If so, keep beveling to the depth of the crack.

The purpose of guttering out the crack is to greatly increase the bonding surface for the epoxy. If there is no evidence of damage to the interior solid ABS layer I would leave it alone and there would be no need to apply an interior patch. I would apply a patch over the exterior crack after you have filled it in with epoxy and sanded the surface fair and flush after the epoxy has cured. I would use fiberglass (6 ounce/square yard, plain weave) for the exterior patch cut with the lines of the weft and weave on a 45 degree bias to the line of the crack for maximum strength. Extend the patch out 2 inches from the crack onto undamaged hull in all directions.

Ideally, you would like to completely remove the exterior vinyl from the Royalex to which you are applying the patch so as to bond directly to the ABS. But if this proves difficult to do without damaging further the underlying ABS I wouldn’t sweat it. G Flex bonds very nicely to PVC (vinyl).

The rationale for removing the vinyl is to prevent the possibility of the vinyl later delaminating from the ABS. If you find the crack extends through and through I would also apply an interior patch.

What type of seats do you have? If they are the molded seats I have turned the bow seat around and then the angle is backwards but the one set of holes can be reused. I then made triangle shaped blocks from exterior 5ply and then drilled two new holes using the same seat. It moves the seat about 8” closer to the center and that’s a plus for trim giving you more storage room behind as well. The triangle blocks will lower the seat a little and IMO is a good thing also. I have photos if you have that type of seats.

In my I’m also 99-100% solo and I removed everything and put a seat much closer to center and turned the tandem to a solo. Added in a bunch of thwarts got rid of the carry yoke and the trim is now perfect loaded or not loaded.

pblanc, Thank you for further describing the game plan I should take and for helping me clear up the misunderstanding I was having about the v-notched material. That makes sense, and looking closer at it again i can see the thinness of the vinyl you are talking about. If you were making this any easier for me, i’d go out and it’d be done already :rofl: I’ll go step by step like you suggest and see what i find. I appreciate all the details you have included.

do you have an opinion about needing to move the seat location after the repair? if i flipped the seats like i was thinking then there’d be a thwart roughly in the spot where the repair would be. Is this a good thing or bad thing in terms of stress on the repair?

bud16415, hi! i’ve seen your soloized canoe pics and the canoe ladder you made for getting your canoe up on your car….cool stuff! this generation penny came with the cane seats but they were replaced with web seats after being damaged according to the previous owners. I have been brainstorming on seat placement but i have a couple concerns about moving away from the stock setup: the balance of the canoe while up on the carry yoke, and i plan on using this canoe for poling too, well as much poling as a person can do around here, so i’m concerned a seat in a more centered position could interfere with the best place to stand. I suppose i could use canoe ‘backward’ while poling if i had a more centered seat and have more room that way. a person could get dizzy thinking about what end is the front with all these changes i’m thinking.

thanks again everyone.

happy paddling!

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For the Royalex crack, use GFlex for the initial repair. For added strength, apply GFlex-soaked fiberglass inside. Consider repositioning the seat to reduce stress on the repaired area.

good morning everyone, I thought i’d take a second and give an update; last week we had some agreeable weather so i managed to go step by step with the information provided in this thread and a few other royalex crack fix threads and now i just need to paint the patches and figure out the seats and i should be good to get her out on the water. she’s not going to win any beauty awards but neither am i so we are a good pair!

removing some of the inner vinyl revealed that the crack did not go all the way through but i still did a patch on the inside of the hull.

one question i still have is about putting a thwart in that area should i do a solo seat or if i swap the seats; would it be better to put a thwart directly above the patch job or would it be better to put it off to one side of the patch? i’m a little unclear how the forces that act on the thwart transition to the side of the hull.

I’d like to give a sincere thank you to everyone who helped so far in this thread.

If you are happy with the repair and the gunwale is in good condition I would not hesitate to place a thwart back in its original position. Just make sure there is a small gap between the cut end of the thwart and the side of the hull.