Saturated deck core

Is there any way to dry a saturated balsa core?

I'm working on a refit of a 20m sail yacht. The yacht had a new Teak overlay deck fitted about seven years ago. Whatever genius fitted it used a screw every 20cm on every strake seam to secure the strakes while the adhesive cured. Later the screws were taken out and the seams caulked. Unfortunately, they were economical with the bedding mastic creating voids under the teak which are now water filled and the water is saturating the core through the screw holes. The core isn't rotten and there seems to be no delamination.

I used a hole cutter to cut away the interior laminate and look at the core in places where we could see water dripping.

Any suggestions (apart from those on the theme of a Viking funeral..)

I've read about vacuum drying in osmosis treatment, would this work?

 

In seven years, the core has deteriorated. Drying it is not enough. You need to replace the core. There isn't a quick or cheap repair, unfortunately.

 

Thanks Gonzo
It looks that way to me too; but have to say, in the places where I pulled off the inner laminate there was good adhesion and the core is solid...just very wet. The deck still feels stiff to walk and jump on.
Nick

 

Could you cut a series of strips out of the inner laminate say 1/2 inch wide then seal off the general area for heat loss and put 2 - 100 watt bulbs in there for a month would that work?


repair with epoxy putty and paint over.

 

Circular saw to cut the glass off, scoop out the balsa. Replace with balsa or foam, re glass.

 

We were considering cutting disks of say 55mm out of the inner laminate on a grid, dehumidifying the interior, monitoring the drying and then laminating over...
but difficult to imagine that the core would really dry that way.

 

Faster and easier to just do it the right way.

 

Aim a couple of fans at the area and you can dry most anything, i t just takes time. and power.

 

Not much power either with a bit of dehumidification. I've seen this used in flood damage situations very effectively.

 

I'm with Gonzo and anyone else who says replace the balsa.
To try to get it dry you need to remove one skin, exposing the balsa completely.
Then you could try to dry the balsa by using a heater and an airconditioner (takes out the moisture).
But when will you ever decide the other side of the balsa is dry?
Since you have the skin off you might as well replace the balsa, cause you will never be able to tell if the balsa has started to rot and what strength is left.

Sorry, but you should consider the new teak just a casualty and build the deck properly.

Short cuts just cost too much.

 

You could always dry it out using microwaves

"I posted an article about this method in the Swedish crusing associations newspaper and there have been a few guys that have used the method and are really pleased with doing so."

http://www.cruisersforum.com/forums/f55/using-microwaves-to-dry-a-wet-deck-core-36006.html

 

Drying out a core isn't usually practical, except in very localized areas, where it can be fully accessed and opened. Fans, blowers, A/C units and even dehumidifiers are a waste of time, unless you can completely seal the boat, less the entry point for circulating air. Don't get me wrong, technically, it's possible, but it'll take many months, not days to dry a soaked core, with few guarantees it's really dry and still adhered.

I have had success with chemical drying on localized areas, but this would be very dangerous on large areas, not to mention costly. This is why the cores are usually just yanked out and replaced.

 

Yes, that's the only practical way to dry it. It got to be a vacuumed to about 0,01 bar thou it depends also a lot of the temperature.
But that doesn't fix the leaking deck..

 

Thanks everyone for the replies.

The boat came to us for an interior refit, but as I couldn't see any sense in starting without fixing the deck leaks I begun exploring. Real shame to see the damage created by shoddy and lazy work on the deck (although it looks good). It's not my call to say what will or won't be done but as pointed out above, whatever is done with the core won't fix the leaks so the teak will have to come off anyhow if the issue is to be fixed.

Thanks for the link to the article on microwave drying, interesting!
Nick