How do you repair hairline cracks in the fiberglass? They are not leaking, but are aesthetically unattractive.
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Mremington, The cracks are in the gelcoat
and are indications of either age or stress. My boat has a spider web of them over its entire surface. If you are very patient and ambitious you can open them with a Dremel tool and fill them with new gelcoat and polish them. Or you can take the approach that was common with old jalopy cars, you can take off the radiator cap and drive a new boat under it.
and are indications of either age or stress. My boat has a spider web of them over its entire surface. If you are very patient and ambitious you can open them with a Dremel tool and fill them with new gelcoat and polish them. Or you can take the approach that was common with old jalopy cars, you can take off the radiator cap and drive a new boat under it.
paint.
Start with a good sanding and thouroghly clean, then spray or brush with very thin paint, each time sanding it back to the gell coat. The paint will seep into the cracks and produce a smooth finish. A couple good finish coats and you're boat wil look like new.
The paint will act like a glue and prevent hairline cracking from showing through.
Buffing 'melts; the top layer of gell coat and is a very weak repair, often showing the hairlines when cooling after you put the tools away.
You want the paint for the first coat to act like soapy water or oil on a hot pan, just spread out like crazy when dripped, that way it will fill the cracks and bind them together, each additional coat should be slightly thicker (depending on how the cracks show)
It is NOT a quick fix, but will be a long lasting one.
Ken.
Start with a good sanding and thouroghly clean, then spray or brush with very thin paint, each time sanding it back to the gell coat. The paint will seep into the cracks and produce a smooth finish. A couple good finish coats and you're boat wil look like new.
The paint will act like a glue and prevent hairline cracking from showing through.
Buffing 'melts; the top layer of gell coat and is a very weak repair, often showing the hairlines when cooling after you put the tools away.
You want the paint for the first coat to act like soapy water or oil on a hot pan, just spread out like crazy when dripped, that way it will fill the cracks and bind them together, each additional coat should be slightly thicker (depending on how the cracks show)
It is NOT a quick fix, but will be a long lasting one.
Ken.
I had a lot of hairline
cracks around the forward hatch of my old C&C. I sanded and painted over them using Interlux White Bootop one-part paint. Looked good for one season. The cracks became visible again. I stripped and sanded the old paint off. Made up a mixture of West System epoxy that was thinner than normal. Very carefully taped of the whole area around the hatch and applied the thin epoxy. Applied a second coat the next day. Sanded and removed the minimal blush and again painted with Bootop paint. No cracks showing more than 5 years later when I sold the boat.
cracks around the forward hatch of my old C&C. I sanded and painted over them using Interlux White Bootop one-part paint. Looked good for one season. The cracks became visible again. I stripped and sanded the old paint off. Made up a mixture of West System epoxy that was thinner than normal. Very carefully taped of the whole area around the hatch and applied the thin epoxy. Applied a second coat the next day. Sanded and removed the minimal blush and again painted with Bootop paint. No cracks showing more than 5 years later when I sold the boat.
same process
Thin paint or epoxy can seep into the cracks and keep them from coming through again.
Don't think it realy matters what type of paint is used so long as it can be thinned and adheres to the gell coat. I normally use a one part polyurethane, but have used others. Only thing critical is that you can thin it, and that it's compatable with succeeding coats.
Normally, when the first coat thin coat is applied, the hairlines will show up HUGE, sand them back and pretty often they'll disapear then. sometimes need another coat or two depending on how deep they are.
Ken.
Thin paint or epoxy can seep into the cracks and keep them from coming through again.
Don't think it realy matters what type of paint is used so long as it can be thinned and adheres to the gell coat. I normally use a one part polyurethane, but have used others. Only thing critical is that you can thin it, and that it's compatable with succeeding coats.
Normally, when the first coat thin coat is applied, the hairlines will show up HUGE, sand them back and pretty often they'll disapear then. sometimes need another coat or two depending on how deep they are.
Ken.
- Jan 22, 2008
- 519
There is a product call Cpt Tolley's creeping crack filler
it is reputed to work well on hairline cracks. Its about $10 a tube. I have never used it opting to used thinned gelcoat instead. It seems to work, but I would not hesitate recommending Cpt Tolley's based on the numerous positive reviews by others. I only mention it here because it has not been brought up in this thread as another option.
Having fixed numerous fg issues on boats however, I agree with others that this is simply a cosmetic issue and not structural. Think of it as top surface shrinking over time without substructure shrinking. With age all fg boats seem to suffer this cosmetic phenomenon.
it is reputed to work well on hairline cracks. Its about $10 a tube. I have never used it opting to used thinned gelcoat instead. It seems to work, but I would not hesitate recommending Cpt Tolley's based on the numerous positive reviews by others. I only mention it here because it has not been brought up in this thread as another option.
Having fixed numerous fg issues on boats however, I agree with others that this is simply a cosmetic issue and not structural. Think of it as top surface shrinking over time without substructure shrinking. With age all fg boats seem to suffer this cosmetic phenomenon.
same thing on my boat...
...all over the place (she is 36 y.o.!!) on deck.
I plan on just sanding and using epoxy primer and 2-part LP this fall to remedy the situation. Prior to that impact damage will be opened with a dremel and filled with epoxy; small voids will be filled with fairing epoxy.
Hopefully, I'll remember to take some pictures....
Interesting to hear all the different ideas and approaches.
...all over the place (she is 36 y.o.!!) on deck.
I plan on just sanding and using epoxy primer and 2-part LP this fall to remedy the situation. Prior to that impact damage will be opened with a dremel and filled with epoxy; small voids will be filled with fairing epoxy.
Hopefully, I'll remember to take some pictures....
Interesting to hear all the different ideas and approaches.
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