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

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)

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

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...


Forget it. It won't come even close to working. You'd have a tough
time getting the water out of that balsa baking it for weeks in a warm
oven.

On Wed, 05 Nov 2008 21:15:18 -0500, wrote:

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

Bruce in Bangkok wrote in
m:

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...


Forget it. It won't come even close to working. You'd have a tough
time getting the water out of that balsa baking it for weeks in a warm
oven.


Are you saying that you can't kiln dry balsa?

Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

On Thu, 06 Nov 2008 11:47:42 +0700, Bruce in Bangkok
wrote:

On Wed, 05 Nov 2008 21:15:18 -0500, wrote:

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...


Forget it. It won't come even close to working. You'd have a tough
time getting the water out of that balsa baking it for weeks in a warm
oven.


Are you saying that you can't kiln dry balsa?


We are talking about completely saturated balsa, not drying green
lumber to get SOME of the native moisture out. Besides, you can't get
it in the kiln while it's still sandwiched between two layers of
fiberglass and attached to a boat. If it's been wet for any length of
time, the balsa is permanently damaged anyway, and replacement is
mandated.

So, in this case, no, you can't kiln dry it.

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)

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


Bruce in Bangkok wrote:
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."


I've used denatured alcohol to speed up evaporation & drying of wetted
core. How much it helped I can't say. This was two years ago and the
balsa-cored section I repaired is still sound... no idea how dry it is
inside since I'm not going to drill test holes just for fun.

I also could not say for sure how much it speeded up the drying
process. The section was less that 2 square feet and I rigged a
gravity alcohol irrigator on one side and a vacuum pump on the other.
It ran for a couple of days and it seemed dry, so I ran the vacuum
pump and a heater for one more day without alcohol

Fresh Breezes- Doug King.

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

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

It's a tough repair which has been discussed on "rec.boats.building"
from time to time in the past. You might be able to find some of the
old threads by searching Goole Groups.

Basically the core is damaged beyond repair where it has gotten wet.
As others have said there are three basic methods:

1. Remove the top skin, replace/relaminate the core, replace the top
skin.

2. Remove the bottom skin, repeat as above.

3. Drill a series of holes, dry with heat and/or a vacuum pump, fill
holes with thickened epoxy, perform cosmetic fix on drill holes.

Method 2 requires working from below which is difficult but may be
easier cosmetically if the repair can be covered by the head liner.

Method 3 is relatively quick and easy but long term integreity is
suspect and the holes can be difficult to cover. The extent of core
damage can be determined by examining the drilling residue.

Method 1 is scary but probably yields the best long term out come.
Some people have reported success making a thin cut around the
perimeter of the repair using something like a Fein Multimaster to
make the cut; lifting off the outer skin intact; and then replacing it
at the end, leaving only the cut line to be patched up cosmetically.
One difficulty is predetermining the extent of the core damage.

On 2008-11-06 00:06:59 -0500, Wayne.B said:

Method 1 is scary but probably yields the best long term out come.
Some people have reported success making a thin cut around the
perimeter of the repair using something like a Fein Multimaster to
make the cut; lifting off the outer skin intact; and then replacing it
at the end, leaving only the cut line to be patched up cosmetically.
One difficulty is predetermining the extent of the core damage.

I did this with Xan's port deck a dozen years ago. Still haven't gotten
to the starboard side. It was really a fairly easy job with our big
flat deck. Might have taken 3 weekends to do the bulk of the work, and
most of that was thinking or waiting.

Surveyor said the delamination wasn't a problem if we didn't see stress
cracks. Still none, so I put up with a bit of spring in my step on that
side.

Tip: A real nice way to chip core out of the corners is to fit router
bits to a 6-12" drill extension with a ball bearing collar between the
bits and extender. Lets you rest against the surface you want to NOT
chip yet get pretty deep -- pretty much the length of the whole
assembly.

--
Jere Lull
Xan-à-Deux -- Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/