Is varnishing a "slightly moist" bulkhead a bad idea??

FishFinder · #1 (**permalink**) 06-09-2008

The wood bulkhead in my boat registered slightly moist according to the surveyor's moisture meter. I'm recaulking the chainplates above it BUT the question I now have is -- would applying a protecting/surface film finish like varnish or polyurethane to this bulkhead be a bad idea? I like polyurethane and I know from woodworking that these types of finishes are good moisture barriers between the wood and air, but maybe in this case I don't want a moisture barrier that would make it harder for the bulkhead to dry out?? Maybe go with an oil finish instead?

artbyjody · #2 (**permalink**) 06-09-2008

Do not do it with moisture still in the wood. It will do the infamous milky milk look once it tries to dry. Do the fixes for the leak and - if possible sand a bit of the area in a uniform manner and place a heater on it to let it dry out. You should probably wait a week or two for it to dry out...(thats why you want to sand to break any moisture sealing that is already in the wood and let it breathe and let moisture out).

Then you should be able to go in and tackle the job properly with the varnish you want....

Rockter · #3 (**permalink**) 06-09-2008

Nothing sticks to wet wood. You really must dry the job first.

arbarnhart · #4 (**permalink**) 06-09-2008

What are the dimensions and wood type of the bulkhead? Do you know the % MC and the RH at the time?

sailingdog · #5 (**permalink**) 06-09-2008

Why is the wood "moist". You really need to find the cause of the water intrusion and FIX IT. If you don't fix it, the wood will eventually rot and then you'll be rebuilding the bulkhead. If the chainplates are anchored to the bulkhead, then you might lose the mast in the process of the bulkhead rotting away.

FishFinder · #6 (**permalink**) 06-10-2008

I don't know the dimensions or RH or wood type unfortunately, I'm away from the boat until next week. Basically the wood felt dry to me, looked fine (didn't see evidence of rotting), but the surveyors moisture meter chirped a little when he ran it over the wood near the chainplates. We looked all over the bulkhead, he didn't seem concerned, just said this area showed a small amount of moisture and I needed to rebed the hardware above it as soon as I could.

It sounds like the consensus here is that I need to concentrate on drying the bulkhead and keeping it dry. And once it's fully dried/no more leaks it won't matter much what finish I use.

sailingdog · #7 (**permalink**) 06-10-2008

One thing you may want to do, if the bulkhead is still physically sound, is epoxy coat the wood, and then apply your finish over the epoxy. The epoxy will seal the wood against further water intrusion, and generally dries relatively clear and almost colorless. Epoxy still needs a finish over it as it isn't very UV-resistant and will breakdown and yellow if exposed to UV long-term.