Re-repairing repairs in Royalex

[AnalogReigns]

I recently got a bargain on a 31 year old Old Town Penobscot in Royalex. It has 4 different, sloppily done, epoxy/glass-mat repairs by the previous owner (see photos). He did them all on the outside (no interior holes or patches are visible), it looks like with automobile epoxy/glass-mat. The 2 major repairs are on the bow & stern keel areas, where no one had ever put on skid plates. I plan on putting on Dynel skid plates (after reading about them here), but I'm wondering if I should sand off, and re-do the current repairs, given how thick and amateurish they are.

They look solid, and I could sand off just a bit...and make the skid plates big enough (really big!) to cover them.

Or I could sand them completely off and start from scratch. (As far as I know....the previous owner did stop it from leaking....)

As you can see from the green ABS showing....the boat badly needs large skid plates....

Any advice from you seasoned canoe repairers????

 

[dougd]

If it was me I'd see if I could sand them off or try to get a putty knife under an edge and see if they pop off, that's worked for me a few times. I wouldn't leave them on as the new layer won't lay flat, those old patches looked like they were gobbed on. In for a penny, in for a pound work wise but in the end well worth the effort. Just my .02.

dougd

 

[goonstroke]

If you do decide to remove, I've found a chisel and rubber mallet works well, much more controlled than sanding or grinding. Don't forget the safety glasses as the crud tends to come straight up.

 

[AnalogReigns]

These patches, though poorly done are very much stuck to the Royalex. The epoxy is as much a 1/2" thick, with maybe one sheet of glass matt underneath. I do have a belt sander, to try to grind them down. So you take a wood chisel to the sides of such things and they pop off? No risk of damaging the Royalex?

 

[Will Derness]

That's an ugly project ahead of you. If you can't lift those repair patches with a chisel I would think it would take an extraordinarily long time to sand it flat. In the past when I've been able to get the edge of an old patch lifted, a vise grip on the patch has pulled much of the loosely adhered patch away.

For fairing the old stuck on patch, use a good steel rasp to grind the patch down. That's removes material pretty quickly

For an old canoe, I would take the easy approach and simply try to feather in a dynel skid plate to whatever old patches tenaciously clings to the hull. It won't get you the perfect hull shape, but it will protect what's left. If you become too aggressive in removing the old patches and expose the foam core, that can be patched fairly easily. A deeper penetration through the hull can be fixed as well, but that is a more extensive repair and will need to be performed both on the exterior and interior.

i see used Penobscots fairly regularl of late, some in pretty good shape, so I wouldn't spend too much energy on this canoe

 

[Guest]

These patches, though poorly done are very much stuck to the Royalex. The epoxy is as much a 1/2" thick, with maybe one sheet of glass matt underneath. I do have a belt sander, to try to grind them down. So you take a wood chisel to the sides of such things and they pop off? No risk of damaging the Royalex?

From the look of the uber-thick gloopy resin and underlying material I am pretty certain the repairs were done using part of an old-school kevlar felt skid plate kit. The fabric sure looks that that kevlar felt, and the resin that once came with those kits was some seriously viscous stuff (urethane resin?).

I have seen poorly install kevlar felt skid plates that looked almost as bad. One issue with those kits was that the manufacturers provided half again as much resin as actually needed, and people would use every dang drop of it when less would have been better.

That was some seriously tough resin. And odorous; it even smelled carcinogenic. Busting it off with a chisel is worth a try; that might work better when it is below freezing.

If the chisel proves unsatisfactory a belt sender and an 80 grit belt would work. Wear a respirator.

If you plan to install Dynel skid plates, or any kind of fabric skid plates, you will want/need to surface to be fairly flush, without big resin globs sticking up. And without any divots of material missing underneath.

 

[AnalogReigns]

Mike: I'm certain there is no Kevlar in these patches. You can see through the epoxy and see fiberglass mat, (not cloth) and that's it. I doubt the previous owner is even aware of the existence of Kevlar patches. When I asked him about what kind of epoxy he used, he shrugged and said, "whatever kind they had at the store....but it doesn't leak!" You are correct though, he used LOADS of epoxy which is what makes it so thick. I have a belt sander with 36 grit sandpaper....(about equivalent to a course rasp) and I think I'm going to opt for the sanding it down so the Dynel will cover-it option. It's a very worn canoe, and I don't want to spend too much time rebuilding it.

 

[Guest]

I have removed excess fiberglass/resin with a "razor rasp"--like a sureform file. It works fast and makes no dust. It leaves a fairly smooth surface if you use it right.
Turtle

 

[Guest]

Mike: I'm certain there is no Kevlar in these patches. You can see through the epoxy and see fiberglass mat, (not cloth) and that's it. I doubt the previous owner is even aware of the existence of Kevlar patches. When I asked him about what kind of epoxy he used, he shrugged and said, "whatever kind they had at the store....but it doesn't leak!" You are correct though, he used LOADS of epoxy which is what makes it so thick. I have a belt sander with 36 grit sandpaper....(about equivalent to a course rasp) and I think I'm going to opt for the sanding it down so the Dynel will cover-it option. It's a very worn canoe, and I don't want to spend too much time rebuilding it.

As a plan, I like it. I think a chisel and hammer is likely to do as much damage as good.

If that is kevlar felt (not a woven cloth, but a yellow felt-like material) under the globby thick epoxy it will fuzz up when the sander gets to it. If the felt was not thoroughly wetted out it will fuzz even worse. Hopefully that uber-thick coat of whatever resin had time to fully saturate the fabric.

If it is glass mat it should belt sander away easier, or even flake off under the sander like a Clark bar from the freezer.

How the original owner managed to achieve that goopy piling on of resin with auto store poly resin and crap glass mat I have no idea

But I have seen exactly that, in similar gloopyglobby what-the-heck-were-they-thinking kevlar felt skid plate installations, that yellow kevlar felt color, the same incredibly thick use-every-drop from this expensive skid plate kit even while it is setting up hot and thick in the pot. Just slop it on there, this skid plate kit was expensive.

If possible belt sand it off as fair as you can, fill any divots flush with thickened epoxy (you may need to tilt the hull on its side and tape the perimeter of the divot), lay the Dynel and repeatedly compress the peel ply layer over that.

Graphite powder or color agent pigment in the epoxy coats as you wish; personally I like the look of graphite powder and a wee dab of black pigment, starting in the initial epoxy coats so it sinks into the fabric and can’t scrape off.

The Penobscot is a wonderful canoe, one of my favorite Old Towns. Well worth saving and putting right. heck, if you get the absurdly thick resin and patches off and add a single layer of Dynel it will lose weight.

Updates and photos please. Could be a vicarious learning experience for all of us.

 

[goonstroke]

These patches, though poorly done are very much stuck to the Royalex. The epoxy is as much a 1/2" thick, with maybe one sheet of glass matt underneath. I do have a belt sander, to try to grind them down. So you take a wood chisel to the sides of such things and they pop off? No risk of damaging the Royalex?

Yep, just a regular wood chisel, usually 1". They may not pop off in big pieces, but you can angle the chisel so you get the wart and not the healthy skin underneath. That said, if there are large chunks of royalex missing and you think the goop is serving a useful purpose as fairing compound, the belt sander might be better for just taking off a layer. But I wouldn't leave too much, the thick resin without cloth is brittle and weak.

 

[Guest]

If you try the chisel first please post back the results. The area in the last photo, where there is vinyl skin missing outside of the resined area, may be especially problematic in lifting the remaining vinyl underneath.

And if you go the belt sander route let us know how that went as well.