Repair on balsa core rot in deck

[Mule]

I dispise balsa. PO(s) did hardware mountings w/o donuting with resin and my fly bridge got lots of water in it. Now this was not localized because of the voids around the balsa blocks. Little rivers of water shifted all over the bridge depending on the list of the boat at the time. This created havoc over time. I peeled the entire deck down to the salon overhead and replaced with plywood and heavy cloth. I should have used sheet foam, but this works well too. Were I buying another boat, balsa would be a deal breaker.

[westsail42]

Nicely done. Thumbs up.

[Cruiser2B]

Looks real good! nice neat and preserved the top skin

[s/v Jedi]

Originally Posted by Mule

I dispise balsa. PO(s) did hardware mountings w/o donuting with resin and my fly bridge got lots of water in it. Now this was not localized because of the voids around the balsa blocks. Little rivers of water shifted all over the bridge depending on the list of the boat at the time. This created havoc over time. I peeled the entire deck down to the salon overhead and replaced with plywood and heavy cloth. I should have used sheet foam, but this works well too. Were I buying another boat, balsa would be a deal breaker.

It's not so much the balsa but the PO you must despise. Also, the builder did not use the SCRIMP process so that it spread all around. You have now closed it up real well but the new plywood core is more prone to spreading water damage than balsa because it is not end-grain.

@all: I just ground every crack topsides and found two that went down into the core. It now looks more like something fell, bounced back up and fell again just next to it. Must have been pretty heavy.

I think the problem was not just the impact but also some little voids under the gelcoat that allowed moisture to wick in.

I injected some resin in the two voids, connecting them with my new solid glass core. The rest is just filling with MarineTex and sanding. This is an anti-slip area so tough to restore small repairs to blend in. I had some practice in it before so I think it'll be okay. I'm gonna have to do much more crack fixing in preparation for a pain job. My gelcoat is now 19 years old and I think I'm the last Sundeer 64 with original gelcoat

My pigments have dried out so it's gonna be white or white haha

[Cheechako]

I did a V berth from below once. about a 3 x 3 ft area. Messy, but didnt have to mess up the new deck finish and it worked.

[Exile]

Interesting & informative thread -- thank you.

That looks like a mighty thick deck -- any idea how thick?

If you had access to say, some G10 material, could you not epoxy in layers of it to fill the bulk of the voids?

I'm looking forward to seeing how you deal with the topsides. Is your non-skid molded in gelcoat? Will you attempt to create nonskid where your patches are? I'm with you on trying to match gelcoat pigment -- white will need to be white!

[David_Old_Jersey]

Originally Posted by s/v Jedi

Which finishes the underside

You could also paint the underside .

Apart from making stuff like this pretty much dissapear , I figured that clean and white (bilge paint) would make any future movement or leaks very visible (should I ever remove the panels again for any reason - probably not ).......plus it simply fed my OCD .

[heron237]

At the risk of getting in here late.... You made a simple repair painfully difficult to observe....I know I've been there.

The whole repair could be made in a couple of hours (two one-hour sessions)....with planing.

I don't understand the scheduled lay up (all that thickened epoxy and then a couple of flimsy layers of cloth), boiling up--a PITA to sand, etc on a simple repair. Since it's an area that doesn't need compressive strength I would: After a long drying out, put down a drop cloth, chamfer the edges 20:1 (thickness of bottom skin) with a 50 or 60 grit grinder, blow out the dust/debris, wash out with acetone, wet out the area with unthickened epoxy, then in the same batch add enough bonding thickener to get a no sag peanut butter consistency with bonding thickener get it in there with an acid brush and butter up my pre-prepared core material press in in there till the epoxy squeezes out. put a sheet of plastic on my pre-prepared piece of 1/4" Masonite or plywood and then wedge my precut piece of lumber between the floor and the repair. A helper would be useful for that.
After cure, remove backer, wash with scotch brite, dipped frequently in a large bucket of water, wash with acetone, sand with 80 grit, paint unthickend epoxy on the repair, and coat your pre cut layers of fiberglass, let it cure slightly and press on and squeegee out the bubbles. large to small pieces to cover your chamfered edges. put your board back up. Or just read:

http://www.westsystem.com/ss/assets/...aintenance.pdf

[heron237]

When you get to the deck and want a non skid area, don't use old gel coat, it doesn't last more than a year or so, always check the date on the can. You could get a serviceable non skid area by simply painting on your activated gel coat let it cure some, and then roll a "rough texture" roller skin over it. Try different methods till you get the best result on a piece of smooth Masonite first.

[s/v Jedi]

Originally Posted by heron237

At the risk of getting in here late.... You made a simple repair painfully difficult to observe....I know I've been there.

The whole repair could be made in a couple of hours (two one-hour sessions)....with planing.

What makes you think I spent more than that? I spent more time on taking the pics and writing in this thread than on this repair and spent well under 2 hours on the repair

There is no flimsy layup with cloth. Cloth is the strongest fiberglass with the highest glass-to-resin ratio (that is on the West System website too I bet ). It is also the same schedule as the original layup in this spot. You would chamfer a 1mm layup 20:1? With a skin this thin, a bit of overlap doesn't matter much, especially not with a solid glass core above it instead of balsa.

Sanding and cutting must be done before full cure, when it is still much easier to do. The only time I wait for full cure is with final fairing.

Last but not least, I don't put gelcoat on epoxy. Nobody should.

ciao!
Nick.

[DeepFrz]

There is a good article about matching non slip in deck repairs on the West Marine Site.

[heron237]

WEST SYSTEM | Projects | Fiberglass Boat Repair and Restoration - Polyester over epoxy

[s/v Jedi]

Originally Posted by heron237

WEST SYSTEM | Projects | Fiberglass Boat Repair and Restoration - Polyester over epoxy

Yes, there has been much debate about it, but most pro's have stopped using gelcoat over epoxy after too much trouble and angry customers. Evercoat also still states it is not to be done, just like Marinetex.

[heron237]

Of course, as they say "would you rather be right or be happy"

Good Luck

[David_Old_Jersey]

Originally Posted by s/v Jedi

What makes you think I spent more than that? I spent more time on taking the pics and writing in this thread than on this repair and spent well under 2 hours on the repair

Yeah, I was well impressed with your posting progress posts with pics in real time .....me would still be trying to seperate camera from beard and eyebrows .

My "secret" for speedy sanding of time harden epoxy is to use a wire brush on a drill even at the price of needing to add some more epoxy (to tackle when still "Green") - but fortunately with a wire brush on a drill plenty of good key for that later fill / coat .