Subject: cored deck repair
Date: Wed, 11 Feb 1998Hi there.....
I have a 45 foot center cockpit ketch with a very wet deck. The previous owner began the repair by drilling holes about 3/8" one inch on centers. He re drilled the holes using a dull drill to make sure he had penetrated to the bottom through the balsa core. Then removed all balsa possible with a shop vac. After this he filled the holes using West epoxy, forcing it in under slight pressure. The result is strong and results in about a 10% saturation in the finished repair which seems ok. My question is two fold. First do you agree with the method and two, do you have a water displacing epoxy? Or perhaps a very thin (thinner than west) that might do a better job? Your help please -
Henry K.Henry:
Yes, we agree with the method, as opposed to ripping off the whole top lam of the deck and replacing the balsa core. We've seen that done more than once but it can be a lot of work.
Our recommendation is to do basically the same thing, and either drill a lot of holes (as the previous owner of your boat did) and vac out the wet wood, or drill fewer holes and let the balsa air-dry or pump air through to blow-dry. Either way, we STRONGLY suggest using our Clear Penetrating Epoxy Sealer (CPES) as the first epoxy application. This stuff will penetrate far beyond the bad wood and into the still good balsa, protecting it as well. It will also displace light moisture. I'd put as much in as it will quickly take (5 minutes or so), otherwise you'll end up filling your entire deck cavity with liquid. (You can look at the Product Testing Section of our web site and see the penetrating advantages of the CPES. The standard resin we used was West.) Then give it about a week or week and a half to cure out.
After that, you can follow with a good slow setting epoxy resin (such as our Layup & Laminating Resin) to fill the holes. The advantage of the slow-setting/slow cure stuff is that it will seep further into the balsa structure than a standard resin. Epoxy putty the holes closed and you're done -- with that section at least.
Given some time, I would go further and pull deck fittings, etc., pour CPES into the holes, and re-bed using one of the polyurethane sealant compounds, such as 3-M 4200. Polyurethane sealants will bond with CPES to give you the tightest seal. This way you are protecting the balsa and at the same time eliminating the source of water leakage into the deck core. Otherwise, you'll just end up repeating and repeating the drill-and-fill procedure. Start at the high end of the boat and work back through any fittings/structures that are thru-fastened to the deck.
Easy for me to say, right, sitting here at a computer? But hey! Try dealing with a 50 foot wood hull built in 1889! Boats are work. If you have any more questions or better definition about the procedure, let me know. We'll help all we can.
Doc