Sealing fiberglass

Hello folks

I'm restoring an old Paceship Sailboat and have a question about sealing the exposed fiberglass on the inside of the hull. The boat was waterlogged so I separated the hull and replaced the rotten stringers with plywood and epoxy/fiberglass cloth, and repaired the delaminated deck using foamcore and epoxy/fiberglass. My question now is should I seal the exposed old fiberglass areas and if so with what? I have already painted the stringers and sprayed CSM with epoxy paint but I'm about to reassemble the top of the hull back to the bottom half and am considering epoxy painting the underside of the upper part of the hull (deck).

Re: Sealing fiberglass

bjurcina said:

Hello folks
. My question now is should I seal the exposed old fiberglass areas and if so with what?

I have already painted the stringers and sprayed CSM with epoxy paint but I'm about to reassemble the top of the hull back to the bottom half and am considering epoxy painting the underside of the upper part of the hull (deck).

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i would not worry about sealing the old glass it self, usually they used a waxed resin. this it self seals the glass.
if the glass is covering a wood structure...then i would put a layer or flo coat of gellcoat on it.
paint would also do the trick.

but if we are talking about bare hull here.....no need.

there are a lot of stories of how poly resin and glass is not water proof......well its not....a molecule or 2 might get past it in 20 years.
but if you are thinking that the seepage thru glass is what caused the waterlogging in the first place....that is incorrect.

dampness caused by condensation, thru hull penetrations, bad rub rail joints are the common causes of waterlogging.

by the way......the epoxy you put on the stringers has fantastic water seepage protection properties...if we were to look at the properties on a bar graph.....
the first coat is good....the second better.....three coats and the protection is tripled.....4 and the amount is exponential.

we would love to see what you are doing.
got pics?

Re: Sealing fiberglass

Wow. I didn't expect a reply from the legendary Oops! I'm not worthy!

I'm sure I've made mistakes in this project but that's how I learn and I like to experiment. Let me know what you think.


This is the boat when I brought it home



This is the floor cut out in the bow to determine the condition of the stringers. They were clearly rotten as suspected. The floor was also very soft and weak.



Pulling the top off



I was surprised to see that all the stringers were laid in with sprayed CSM and in many places the resin could not have been flowing properly during the process as you could reach down and pull out clumps of fiberglass strand that was not mixed with resin. This is why I decided to seal all the remaining stringers with one part epoxy paint, to fill any holes and to increase strength in any potential week spots.



Stringers starting to go in



I'll upload more later

Re: Sealing fiberglass

Here's the floor coming apart. After 2 or 3 months in a dry heated garage tied to the ceiling, the balsa filler in the floor was still dripping wet.





Here it is with new foam core and meranti filler in the seating area.

Re: Sealing fiberglass

I'm about to reset the top back on but I need to decide what to do about flotation. I may just reuse the old stuff but I'd like to put in something clean and fresh. I'm leaning towards blue or pink EPS.

Re: Sealing fiberglass

looks like you are doing a great job so far !

the wet balsa core is really a pita !

since the foam is not structural.....a lot of the guys are using the blue or pink stuff.

when you put her back togeather....just make sure you really seal the joint.
that is a flange joint.....thats why you had so much trouble taking it off.

but really really good work so far.....not long now and you are back on the water !

Re: Sealing fiberglass

bjurcina said:

Wow. I didn't expect a reply from the legendary Oops! I'm not worthy!

Click to expand...

Dont worry .. He has the same left and right shoes that we all have ..

Actually .. it came to my attention that a few weeks back he forgot which one was which .. ( I think the little white stickers fell out of his shoes or something.. I cannot confess one way or another due to slight blurry-eye syndrome myself .. .. )

Good work though ..

YD.