Dry out moisture?

[andysailor]

I have some high moisture readings on some wood on my boat. It's the cross beam. Might be Douglas 6" x 2"

Readings are 40-50%. Wood looks ok, not roten, so not sure how to read it. What can I do? Replace it would be a nightmare. How bad is it? Dry out?

 

[fallguy]

If you don't know the wood, what meter are you using for the reading? Many meters require calibration to a specific wood type. What sort of wood beam would you have that is not encapsulated in epoxy and glass? Pictures?

 

[andysailor]

The meter is a regular one where it´s only is possible to choose between wood and another material. I push to spikes into the wood and get moisture percentage. I get normal reading around 10-15% everywhere else.

The beam is a box beam. I have taken off a piece of the plywood from the box to get to the inside of it. On the inside it has been coated with some kind of resin but water seems to have come in thru an inspection hatch. I have sanded off the resin to use the meter.

 

[Steve W]

Make sure your meter is set for the wood type, ie softwood or hardwood. If its the crossbeam on a multihull it is highly unlikely to be hardwood so Doug fir is probably correct so it would be set to softwood. I have taken readings on a simpson cat and where we metered the foredeck and found high readings when we cut a hole to install a solar vent we found the plywood to be perfect so a visual inspection is more reliable if possible.

 

[Steve W]

Oops, I missed your last post.

 

[andysailor]

How would the changes be to remove some of the resin, install fans/blowers. Making sure no water can get there....
Would it be possible to dry it out, over time? How much of the resin would I need to remove? On a couple of places or the whole thing?

 

[fallguy]

Was the build epoxy or poly or vinyl?

 

[andysailor]

Was the build epoxy or poly or vinyl?

Hard to tell...

 

[fallguy]

I would pull it; bring inside; tent it with a dehumidifier; grind off resin n glass.

Or build new with epoxy n glass, so it can drain or with a pie eye inspection you don’t open.

Sorry, but high moisture means water got through so not epoxy or not glassed.

 

[fallguy]

Personally, I’d rebuild it better.

 

[andysailor]

Bring inside is not an option cause there is no place to do it here.
The whole box beam is about 7 meter x 60 cm. It's attached to the main aft bulkhead. The box beam itself is built into the aka.

If it would have been straight forward I would probably built a new one...but it's such a huge project...and just trying to find other solutions

 

[PAR]

First off, get a better meter, as the cheap, non-adjustable ones aren't very good, except to give you a general idea for comparative purposes, such as checking stacks of seasoning timber. In this role, going from one piece to the next will give you some idea of content, particularly relative to one's around them. To get more specific, the meter needs to have a few adjustments, which you'll see on the more costly units (of course).

 

[fallguy]

Quite a predicament.

I can only offer my thoughts. Others here might be wiser.

First, I’d get on the hard if you are not. You need to find dry air eh? Not gonna happen over the sea in winter.

Then, I’d try to remove the poly from the inside of the beam. It sounds like poly; epoxy would not have probably allowed ingress.

Then I’d try to run heated air through the box. The trick here is to heat the box without catching it on fire, so you’d put the plywood back on and hole it for a bilge blower type of thing. I can’t advice you on btus, but you want the heat to warm the entire beam, so something like 120 degrees output and like a bilge blower speed; perhaps less. Then wrap the beam in insul and plastic for weather.

The best air heat inlet would be conditioned air from inside. Running damp air through is going to take forever.

 

[fallguy]

PARs advice is good. A better meter and more samples is also wise. If you have only localized moisture; no reason to run hot damp air through dry sections!

 

[fallguy]

And 40-50% MC can be felt to the touch for a seasoned woodworker.

That is really very wet. The wood will NOT dry with the encapsulation. Consider it might have taken years for the ingress to occur.