Stanchion Fiberglass Repair

[Bowdrie]

As has been mentioned already, I too would go with an external repair.
After an external "flush" repair, I would be tempted to use some thick G10 to form "pads", if you will, externally set in epoxy mush to re-fasten the stanchions to.
Perhaps ~twice the fore-and-aft dimension of the bases and somewhat taller, suitably curved with a grinder to fit the inside curve of the bulwark and edges beveled.
Done with care such a job can have a good appearance, you'll have to re-paint/gelcoat anyway.
You might also consider doing all of the other stanchions as time permits.
The leverage forces involved are huge, and weak/flimsy stanchion bases are to be found on many boats, (no matter the make/model/cost,) and offer only a false sense of security.

[Spot]

In regards to adding an external pad, could a person vacuum bag 5 layers 1708DBM + resin externally to the stanchion areas or create a pre-form/mold instead of grinding any sort of of flat G10 plate to fit the contours?

[Bowdrie]

Originally Posted by Spot

In regards to adding an external pad, could a person vacuum bag 5 layers 1708DBM + resin externally to the stanchion areas or create a pre-form/mold instead of grinding any sort of of flat G10 plate to fit the contours?

I suppose you could.
That's a lot of work with messy stuff, the vacuum bagging wastes a lot of resin and you're still left with a surface to bolt to that will require a lot of on-your-knees fairing and sanding around the perimeter.
The curvature might be so slight that no grinding would be needed, repair the original surface more-or-less flush, (or above flush in the center,) and stick on a G10 part over the repair with epoxy mush, fillet around the edges and be done except for paint.

[yournamehere]

Thank you everyone for your help!!!

[gulfislandfred]

Can you give us pictures of the inside?


peel off a chunk of the damaged surface to get the scanned paint match. If it's Awlgrip, it may be a standard colour. It can be hard to get other paint to stick to awlgrip. Surface prep where new paint finish meets old needs attention.



The patch job is pretty straightforward: Grind out all the damage, taper the edges, glass with your choice of resin, use light mat at the interface and cloth to build up.



If there's room, I would grind out and repair the glass with epoxy resin as described, then put an aluminum or 316 stainless backing plate inside, 8 inches to a foot long, through bolted with the original stanchion bolts, and set in epoxy resin with silica or 3M 5200. Make the bolt holes a little large for ease of attachment, and use double fender washers inside for strength.



Or make pre wetted patches of 5 cloth with epoxy resin (or vinylester - but I'm too old to have any experience with vinyl, don't know properties or strength) and lay two or three of those patches inside, (if the G10 is expensive or hard to find)
Or make those patches outside, let 'em harden, then put them in, like the G10?


Decision time: It it worth the trouble to put backing on all your undamaged stanchions? Can 6'3" big buddy fall on the current stanchions, and stay on the boat?

[Dave9111]

So this is both a suggestion and a question. Having never worked with Vinylester before.

If this was polyester/fiberglass and this break had recently occurred so the surfaces were relatively clean inside the broken areas, I would suggest mixing some epoxy and pour/brush it into the broken area, then drive some screws or bolts through a the broken area into a backer block of wood, wax the screws, and sandwich with polyethylene film so every thing will release. That should make the broken area solid again. Fill as needed. Install a substantial backer block behind this area which more than covers the broken areas, G10 with epoxy, so it bonds to the backside, etc. Then fill, sand, gel coat, or paint.

I would think this would be the best solution. Reason being that it should pull the shape basically back into place. A ton of grinding and filling is not required, and when you are done, the proper heavy backer is in place as it should have been.

I'd like to hear some critique of my proposed solution. I'm simply not a big proponent of the "grind every thing away and start over approach". Too much time with little to gain.

What do you think?

Dave

[yournamehere]

Originally Posted by gulfislandfred

Can you give us pictures of the inside?


peel off a chunk of the damaged surface to get the scanned paint match. If it's Awlgrip, it may be a standard colour. It can be hard to get other paint to stick to awlgrip. Surface prep where new paint finish meets old needs attention.



The patch job is pretty straightforward: Grind out all the damage, taper the edges, glass with your choice of resin, use light mat at the interface and cloth to build up.



If there's room, I would grind out and repair the glass with epoxy resin as described, then put an aluminum or 316 stainless backing plate inside, 8 inches to a foot long, through bolted with the original stanchion bolts, and set in epoxy resin with silica or 3M 5200. Make the bolt holes a little large for ease of attachment, and use double fender washers inside for strength.



Or make pre wetted patches of 5 cloth with epoxy resin (or vinylester - but I'm too old to have any experience with vinyl, don't know properties or strength) and lay two or three of those patches inside, (if the G10 is expensive or hard to find)
Or make those patches outside, let 'em harden, then put them in, like the G10?


Decision time: It it worth the trouble to put backing on all your undamaged stanchions? Can 6'3" big buddy fall on the current stanchions, and stay on the boat?

Thanks for the write-up. This is pretty much in alignment with my plans. I fortunately have G10 to use as a backer. My plan (future) is to use this for all stanchions as per the recommendation of the surveyor. My understanding is that I'll have to sand down G10 with rough grit sandpaper to help vinyl ester stick.

As far as the paint, I spoke with the boat building and they confirmed that it is gelcoat. Not sure if that is going to make my life difficult or not as I have not worked with gelcoat in the past.

[gulfislandfred]

Gelcoat is easy to work with.
Just be aware of the wax. Finish coat gelcoat has wax in it, that comes to the surface, cuts off air, and lets the gel coat harden completely.


Wax free gelcoat, or polyester resin, never completely hardens if it is not covered with something.



You can use oil base paint, or other good paint, on top of the glass/resin if you like.


The only issue with the no grind, fill and add backing approach is that the damaged glass will tear more easily where it is torn now. If the tears are ground out, and glassed with appropriate overlap, the laminate will be as strong or stronger than the original.
Is the old damaged glass, with torn areas, just filler between the stanchion and backer, or does it have a structural purpose in the system?

[Noahr]

Just a heads-up. Vinyl ester resin has a very short shelf life (even when unopened). Only buy from a reputable dealer and check the age.

[bil56]

whatever the resin used, finish each layer (if stopping for a few hours/days) with a peel ply, easy overcoat, easy sanding ...

[Seaward22]

One thing to consider is what your typical load will be on the stanchion and with that consider: the larger the backing plate the larger the hole, when you unintentionally use it as a fender.

If you use West System I would cut out all your glass mat before hand, get a suitably sized board to wet the mat on and then squeegee the wetted mat till it almost looks dry. Had some I believe lighting strike pin holes in my hull which I cutout with a 2” hole saw did a 12:1 diameter feather, based on the thickness of the glass. That was probably 8 years ago and it’s still holding and I pound the boat. West System engineers were very helpful when I called them. Agree matching the gel coat is an art. My boats 37 years old so I’m over the cosmetic phase and just use Marine Tex for gel coat since scars are tattoos with a better story. You can put a glass finish on Marine Tex with some plastic wrap and tape, and it seems to have, in my experience, good UV resistance unlike West System epoxy which doesn’t.

[Mickeyrouse]

The reinforcing fiberglass to be applied on the backside should extend well beyond the damage area. Any polyester, vinylester, epoxy, 5200, or whatever will act as a filler well enough, but it will not be a strong enough bond. What that does is essentially create a butt joint with the ends of the fibers, and while it may be waterproof if not further stressed, it just won’t be strong enough. Replacement cloth needs to overlap. I’d recommend at least the distance of the damaged area, and when it’s finished, use backing plates on this and other stanchion bases.
If it got under a dock, or someone stood on it or something that equally overloaded it, it can happen again. Those shiny poles aren’t just decorative, either. They call them “ lifelines” for a good reason. And they have been known to fail too often in crucial moments.
And when this is all done, then you can tackle color match.