Water ingress balsa core seems soft

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Whiterose

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I have a leak through coach roof small amount of water.It appears to come from a mast deck fitting.This has been fitted with hole through deck , core and inner GRP without sealing with resin .The balsa has got wet from this and tracked down to where it has come behind the foam backed vinyl (which has come away).
What’s best way to tackle this wet balsa ...larger than small hole and scrape.Can I seal up leak and leave?Can you inject expanding foam sealant?
Is there anyone who does this type of repair well...reasonably priced?
Cheers
 
Wet balsa core is common, it will go rotten in short order especially if in lower parts of the hull. In decks the deck will lose its stiffness & the water ingress will spread & make it worse. The core is bonded to the deck moulding in panels then covered with a thinner layer of glass when the deck is laid up. This means on a repair you have to work from underneath, best option is to cut the inner skin away remove the bad core & replace before glassing up again. If the area is small you might get away with drilling lots of holes letting it dry then injecting epoxy. Expanding foam sealant would be no use whatsoever. As for cost? Its a poxy dirty itchy job working overhead. A good grp man will want good money.
 
It a terrible job so hopefully it hasn’t spread, I’m half way through replacing the core on my motorboats forward deck and it’s taken 3yrs so far as I can’t bring myself to get back in there, best bet is to cut a small square of the underside fibreglass around the hole and see how far it’s gone then carefully chisel out the rotten stuff, replace and glass up. Holes through balsa need drilled larger, filled with epoxy and then drill for the fitting and there are a few ways to do it, better check your other fittings or you may get good at this
 
There is an alternative way to fix this problem. Temporarily seal the underside of the hole, suggest butyl rubber and polythene. Fill the hole with anti-freeze and allow to soak in. Leave to dry as this will remove the water from the balsa core. Then spin an alum key in the hole to remove a ring of balsa core. Vacuum any debris from the hole. Cover the deck with some wide electrical tape and cut open for the hole. Now fully seal the hole using liquid epoxy, it may need more than you think at first. This will bond the two parts of the sandwich and stop any compression. Grind back with a Dremel the top of the hole and seal with gel coat filler, sand, compound and polish. Remove the bottom seal. Drill a new hole for the cable.
 
I’ve been through this exactly. I ended up cutting out a panel on the inside about 2 foot square and replacing the soggy core then fitting the panel back. Not much fun. I was quite surprised how little the balsa dried even when laid out in the sun as I had hoped to dry it and refit it. This plan didn’t work as when the balsa dried it shrunk which caused the panel to curve.

I have large areas of deck to do at some point which I’m not looking forward too. I will not be doing this from underneath as fairing and refinishing on the outside will be the lesser of two evils.
 
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I had a soggy side deck on a Jeanneau 25 5 years ago. Rotten balsa core.

The job, done once ashore and inside, cost me GBP 1500 when done by a local boatbuilder. Yes, of course I had to have the mast taken down anc moved/blocked off a few times.

He did a reasonable job too (but he did it in his own time over a couple of weeks; you'll pay more if it is done by a 'shiny', full-service boatyard).

He did it from the outside as it was easiest and also fixed one of the hull to deck knees that had come unstuck from the underside of the deck.
 
If you are happy with a plain nonslip painted deck/coachroof top the best repair is probably from the top. It's major work unless the water ingress is only over a small area. A lot of Dufour Arpeges had this done.

I can vouch for the fact that working GRP from the underside is a truly horrible job, and horrible jobs usually get done badly. Long ago I foolishly bought a boat with water in a balsa-cored deck. It was still wet in places when I sold it.

Unless as said only a small area, a cheap professional and effective repair is impossible. You can have any two of the three - ie cheap and effective (lot of work), cheap and professional (not long-term effective) or professional and effective - NOT CHEAP.

Not at all convinced the "antifreeze answer" will remove the water, though the glycol will probably retard the rot.
 
jwilson said:
Not at all convinced the "antifreeze answer" will remove the water, though the glycol will probably retard the rot.
Click to expand...

Me either. Pore spaces in wood (plant xylem) are intended to wick water, not the much larger glycol molecule, which may enter as even larger globules. I would expect (if it is possible at all) you have to drive it in under prolonged, sustained pressure- the sort of thing one achieves in a laboratory and not a marina, in order to achieve a meaningful glycol saturation of the balsa. Happy to be proven wrong of course.
 
I am just into repairing two main mast chain plates on a wheelhouse roof. I did the drill out and allen key trick and ended up cutting the inside layer of glass out to a square of about 10 inches to find dry wood. I intend plating it with 18mm ply, suitably treated with 2 part and then bonding it in place. I was going to use standard West epoxy to peanut butter but was recommended to use a Scott Bader stuff for bonding as it is less brittle when cured. If I hadn't had that suggestion I would have sealed the ply with epoxy, then epoxy bonded in place and glassed over where I cut back. If anyone has better ideas I would gratefully accept them. Thanks
 
Thanks for the quick response. I have dropped a line to the company to ask how I can get some of this stuff. We also have a very spongey bit of deck in the wheelhouse and I am thinking this might just be the answer to a maiden's prayer.
 
Scotsailor said:
Ive seen a new product for sale that’s supposed to fix this problem
https://injectadeck.com

No connection with the product. I have no experience of using it. I would be interested to know if it works though.
Click to expand...

Me too, I've wondered whether there exists some industrial type foam material that would do this ? Would be useful to know if this stuff works or what it actually is
 
I emailed injectadeck and they replied very quickly. They don't have a UK distributor for this product but they are happy to ship it in to UK from the US.
I filled in the contact form on their website www.injectadeck.com. They replied from injectadeck@gmail.com and in their email response they wrote (cut and pasted just as it came in):

'All you have to do is give us your UK address no PO boxes please and we can ship straight to you with the bill of lading in custom certificate we have ship to the UK before we rather not ship to Ireland because they're lower limit on import tariffs is $182. Everyone else is it about a thousand dollars did this is where they charge you incoming tax for things you purchase off of Amazon or wherever.
We would be happy to help we'll wait for the address.
The injectadeck team'

Hope this is helpful. I am not sure the owner of the boat I am working wants to use it, expressing the desire to go with cutting out and bonding hardwood ply into the sandwich in a more conventional manner.
 
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Sorry to hear about your boat's problem. I hope this stuff is the answer to a maiden's prayer. Not sure if we will use it as we have enough time to cut out and repair, and we are doing all the work ourselves. I would also be interested if anyone else gets to use it though. Best of luck with your Westerly, great boats.
 
So a 33ft Westerley Discus for only £7k because the hull is no longer sound … this would be an excellent buy for someone with a sound 33 ft hull but no engine, mast, sails, interior etc etc. …although the chance of finding someone in that situation must be very slim
 
I just looked at injectadecks website, It sounds very like a fancily packaged polyurethane foam of some sort. Most polyurethane glues are moisture cured.
My betting is that if it sounds too good to be true it probably is. Snake oil.
 
"Fill the hole with anti-freeze and allow to soak in. Leave to dry as this will remove the water from the balsa core."

Antifreeze? I doubt it would drey out very easily. Maybe acetone?
 
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