Wet core.... epoxy

Tim R. · May 15, 2010

Epoxy thickened with Cabosil will do just fine as long as the structural skins above and below are still intact.

Dalliance · May 15, 2010

You probably should not fill the whole area with epoxy all at once because that quantity of epoxy could get hot enough to damage the fiberglass. You took wood out. Why not put wood back in and fill the remaining voids with a smaller quantity of epoxy?
I made a similar repair around a leaky portlite this spring -- Loosely filled the void with small scrap strips of wood, then injected epoxy thickened with coloidal silica. The wood is effectively encapsulated.

Ctskip · May 16, 2010

I'd think about mixing sawdust and epoxy. Try filling the hole with as much sawdust as possible then blend up some sawdust and epoxy and fill full with that.
There is the heat factor to consider when using large amounts of epoxy all at once. You mention that all is dry. I must at this point ask, has all the rot been eliminated? The rot will continue to spread even thought it's dry. The rot is actually a microbe that lives and will continue to live till it's been neutralized or removed. My understanding is that glycol (antifreeze) will neutralize the microbe. The only problem with wood treated with glycol is it will not absorb epoxy very well. But the rot will stop. I got real smart when doing my cockpit sole just last month. I dug out as much rot as I could, then soaked (poured) it with glycol allowed it to dry for a week with a heater underneath it. Then replaced any missing wood and soaked (poured on) it with epoxy. Several pours. The Internet is a wonderful place. I now tell people I became just smart enough to be dangerous. Get the good epoxy , not the cheap stuff. One is flexible and the other isn't. Do your homework. Good luck!
Take it for what it's worth. Maybe somebody will correct me if I'm wrong. Please do.
Thats my story and I'm sticking to it. It's what I gleaned off the internet. I poured over this rot and epoxy for two months till I felt confident i was doing the right thing. I think I did. It's strong and no bounce at all. I know it's gotta repel any water that will find it way in, it just has to.

Keep it up,
Ctskip

LordNelson · May 16, 2010

if you use saw dust, i wonder if sawdust from pressure treated wood would be any advantage?

RON20406 · May 17, 2010

NYSail said:
Hello all.....

It's that wonderful time of the year!!!! Was taking deck hardware off the boat, over-drilling, filling with epoxy, then redrilling.

One of the fittings though is a u-bolt that supports my baby stay on deck and attaches to a rod that is afixed below deck to the floor... structurally supporting. Took it out and found the core to be very wet. I have dug out wet core, drilled holes further out and dug out more wet core. Now all is dry, but I am left with a 4" by 6" +/- hollow area. Is plain epoxy good enough for this application or should I stuff some fiberglass cloth in and combine it with the epoxy. I called West System and they said the epoxy will be just fine.... Just looking for additional opinions.

As always, I am greatful for all your wonderful advise!!!

Greg
s/v Four the Soul
Pearson 36-2

Greg, I would agree with the concerns about over heating when adding thickened epoxy to the void, but I would flush the void with acetone to leech any moisture that remains, after the acetone has evaporated dry it with warm air (don't get too hot with a heat gun- use it on low and allow it to cool between applications) and when you feel it is dry, apply CPES which is a very thin penetrating epoxy which will actually neutralize any residual moisture and fill any crevices or voids before the repair. To acclerate drying, you can drill a grid pattern with a 1/4" bit about 1" apart. After that, you can fill the void with thickened epoxy. Unlike most, I would remove the top layer of fiberglass and replace the core material with original and reglass. This, of course, takes more time. Good luck, Ron

Ctskip · May 17, 2010

"I would flush the void with acetone to leech any moisture that remains, after the acetone has evaporated dry it with warm air (don't get too hot with a heat gun- use it on low and allow it to cool between applications) and when you feel it is dry, apply CPES which is a very thin penetrating epoxy which will actually neutralize any residual moisture and fill any crevices or voids before the repair. To acclerate drying, you can drill a grid pattern with a 1/4" bit about 1" apart"

This is fine, but what would you do with the wood that is already rotted (albeit dry, but still active fungi) and still between the layers of fiberglass? Use a boric acid to neutralize the fungi, then dry, then treat with CPES which is a excellent product if used properly.

Keep it up,
Ctskip

RON20406 · May 18, 2010

Ctskip said:
"I would flush the void with acetone to leech any moisture that remains, after the acetone has evaporated dry it with warm air (don't get too hot with a heat gun- use it on low and allow it to cool between applications) and when you feel it is dry, apply CPES which is a very thin penetrating epoxy which will actually neutralize any residual moisture and fill any crevices or voids before the repair. To acclerate drying, you can drill a grid pattern with a 1/4" bit about 1" apart"

This is fine, but what would you do with the wood that is already rotted (albeit dry, but still active fungi) and still between the layers of fiberglass? Use a boric acid to neutralize the fungi, then dry, then treat with CPES which is a excellent product if used properly.

Keep it up,
Ctskip

Ctskip, This is why I always prefer to remove all degraded core material, recore and reglass. Whenever you take a shortcut, you must except the possible negative consequences of your repair. I suppose it relates to your ultimate goal: faster repair time vs. proper (usually time consuming) repair. Best, Ron

Ctskip · May 18, 2010

Replacing all the rotted wood is the best possible repair. Sometimes though, thats not always possible, short of rebuilding a cabin top. I just repaired a portal that was leaking. The wood was soaked. I dried as much as I could, not owning a moisture meter. I then soaked it with Boric acid mixed with glycol and then force dried it, then CPES'd it. Just this AM I replaced the portal with 3M 4200. The screws now had something to bite into.
You are 100% correct in that replacing all the rotted wood makes for the best possible repair.

Keep it up,
Ctskip

tommays · May 18, 2010

I not gonna tell you to get this crazy

But i cant picture a 4 x 6 area being cleaned out well enough to get a good bond