spider cracks

[dorourke]

I have an older boat with a balsa cored deck and want to head off any rotting that might happen from spider cracking.How can you seal spider cracks without drawing too much attention to them, meaning, can you seal them without it showing too much? Do you need to use a gelcoat type of sealer?

[sailingdog]

Dorouke-

You can use this product, which several friends have used with pretty good success.

[SEMIJim]

Is this really necessary? It's my understanding that such "cracks" are just stress cracks in the gelcoat, not the underlying fiberglass. It's my understanding deck core compromise comes from leaks in through-deck fittings, such as chainplates, grab rails, cleats, travelers, winches, the mast step, hatches and so-on.

[sailingdog]

Spiderweb cracks or crazing of the gelcoat are usually caused by old age. Stress cracks are usually parallel lines close to the stressed area. In either case, if the cracks are deep enough to penetrate the gelcoat layer, they can let water into the laminate. It is better to seal them than leave them alone, especially if you're not sure how deep they run. That said, it would also be a good idea to find out what caused the cracks, and if it is an on-going problem, to fix it.

[camaraderie]

Semi...
The other issue with gel cracks that do NOT go through the laminate is that in colder climates, the moisture they let in freezes and expands which can then open up your laminate and expose the core to moisture. No big deal to attend to.

[SEMIJim]

Hmmm... Interesting. Glad I saw this thread. I've had numerous people here in real life tell me such cracks are to be expected on any "older" boat, are generally no big deal and are more trouble to fix than it's worth.

Jim

[USCGRET1990]

check this out...
gelcoat: Information from Answers.com

[USCGRET1990]

Or this...Gel Coat
Gel Coat

[dorourke]

OK, I think I understand about the spider cracks now. It's the gelcoat and not the laminant. I think I've already headed off any core rot by pulling and resealing all the thru hulls I could before I did anything else on the deck.

So This is then what I want to do:
I should seal gelcoat cracks so moisture doesn't freeze and chips away any more gelcoat. BTW, thanks for the weblinks, very informative!

[sailingfool]

Originally Posted by dorourke

OK, I think I understand about the spider cracks now. It's the gelcoat and not the laminant. I think I've already headed off any core rot by pulling and resealing all the thru hulls I could before I did anything else on the deck.

So This is then what I want to do:
I should seal gelcoat cracks so moisture doesn't freeze and chips away any more gelcoat. BTW, thanks for the weblinks, very informative!

Do you really mean thruhulls, or did you want to say deck fittings? Thruhulls would spoeak to the hull itself where any crazing would be a concern. Spyder crazing around deck fittings like stanchions is a common occurance, and my own personal opinion as a New England boater is they can be ignored other than for cosmentic reasons. The few spider crazings on a friends '77 look the same now as they did 20 years ago.