On Wed, 05 Nov 2008 19:39:11 -0600, Geoff Schultz
wrote:

Bruce in Bangkok wrote in
:

On Wed, 05 Nov 2008 17:00:02 -0600, Geoff Schultz
wrote:

Towards the end of our last trip we noted that the top of a cabinet
had a water stain on it. After much lookng I determined that the
water was leaking through the cored cabintop thru a screw hole onto
the cabinet. Today I pulled out a suspect porthole and found a chip
missing from the epoxy that seals the coring and this was letting
water seep in.

It's fairly obvious that the coring is soaked. How do I go about
drying this out before sealing the leak and replacing porthole?


-- Geoff
www.GeoffSchultz.org

I had a similar problem with a deck and did some research. there seen
to be three basic methods.

One: cut away either the inner or outer skin until you reach dry core.
Remove all wet core, replace core and re-skin. - A proper, expensive
and permanent repair (Note the word EXPENSIVE).

Two: Use some form of heat to dry the soaked core. I read about one
individual who jury-rigged a microwave oven. Removed the door and
bypassed the safety switch. Sat it face down on the deck and plugged
it in. After considerable thinking I rejected that scheme as I
reckoned one might generate sufficient steam to explode the deck.

Three: Bore a number of holes through the outer or inner skin, say one
per square inch, until you reach dry core. Vacuum bag area until core
appears to be dry and fill holes with epoxy putty.

Unfortunately, if you do not completely dry the core you will have
problems in the future and, unless you use method 1 you won't know
whether you solved the problem until the core softens.

In any event, I used method 3 and no evidence of a failed core, so
far.

As an aside: If you completely saturate a plywood core and then seal
it up it will take from 2 - 3 years for the saturated core to turn to
a black mush. Don't bother to ask me how I discovered this bit of
information.

Another point to consider - what type of core do you have? If plywood
or balsa you will need to dry it. If structural foam it is possible
that it is a closed cell foam and cannot absorb moisture.

Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

I have abalsa core.

I could swear that I read about infusing an alcohol(?) solution which
attracted water and evaporated quickly...

-- Geoff
www.GeoffSchultz.org


If you mix alcohol and water you get a mixture that will evaporate at
a lower temperature. However, whether this mix will take place
throughout the saturated area and whether the mix will totally
evaporate and leave a dry core, is another question.

But try it. As I implied, the only sure method of ensuring that all
wetted core material is removed is to de-skin it, so all other methods
are really sort of "suck it and see" solutions. Thus my caveat that
there is "no evidence of a failed core, so far."

Another method that I did use once, but is a miserable job, is to
drill holes every inch or so all over the wetted area. then bend the
tang of a file into an "ell" and dig out all the gorp you can dig out.
Then pour mixed epoxy resin in the holes, quickly plugging any holes
that overflow, until you have encapsulated the whole area with epoxy
(Now pray that the large amount of resin is not going to get too hot)
and when the epoxy sets up plug and fair with epoxy filler. Sand
smooth, prime and finish paint.

Even if you don't get all the bad stuff out you will have reinforced
the structure so well that whether the remnants rot or not is probably
immaterial.

But it is a miserable job!


Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)