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Question: After removing the core and outer fiberglass layer in a 2x2 foot area,
when I replace the core do I need to use something other than solid
fiberglass? Provided I can lay up that much fiberglass, is there any
disadvantage to not using another coring material? other than cost and time?
You should put some new core into the deck. Solid glass is going to
add an awful lot of weight for being up that high. Cored glass is
more rigid than solid glass, I think. Also, you have to
put the glass in a few layers at a time or the heat generated will
weaken the bond. I recommend using a high-density foam core where you
replace the balsa. I used klegecell (PL-75 3/8" thickness), a rigid
polyester foam sheet. I
got it from Fiberglass Coatings
(800-272-7890). That's also a good place to get glass cloth and
mat. They're good people, and their web site is improving. (As of 2011, I hate their current web site.) Calling on
the phone works well, too. Ask for their catalog, while you're
at it. There are other good sources, too. Many places that sell fiberglass and resin will also sell foam coring.
Jim Mennucci's articles on deck repair (in the Alberg 30
Maintenance Manual) are a good source of advice,
as is Don Casey's book "This Old Boat." I recommend reading both of
them. My short description of the process is as follows:
- Cut away the top laminate and expose the wet or rotten core.
You generally see recommendations for using a router or saw to
cut away the laminate, but I just use the
grinder figuring
that I've got to grind a bevel for laying up the new glass anyway.
- Dig out all the wet stuff. In some places, I had delamination
but the core was still dry. I left that core in place.
- Grind the top of the lower laminate to make it clean and give
a good "tooth" for adhesion. Grind the edges of the hole in
the upper laminate to a very gradual taper, at least 8 to 1.
You want a broad area for a strong bond.
- Cut the foam core to fit the hole. It doesn't matter how many
pieces it takes, just fill the space fairly completely.
Take the core back out and set it in a convenient spot.
I generally cut the fiberglass to fit at the same time
so I can lay it down dry to make sure it fits. It doesn't
have to be perfect, it's going to stretch and move, anyway.
- Mix up some polyester resin and add some thickener, such as
glass beads, to make a wet paste, something like toothpaste.
- Pour this into the hole and put the foam core back in on top
of it. Lay a small sheet of plastic down on top and put a
weight on top. This holds the core down to ensure a good
bond. The plastic is just to prevent the weight from being
glassed into the boat. You can also do fancy stuff with
vacuum-bagging, but that takes a bit more knack. I've done
better using a weight.
- Clean up your tools and such while you let this harden. You don't
need to let it cure completely before continuing, but it
does have to be solid.
- Laminate new glass on top. I like to start with some thickened
resin on top the core, to fill any gaps, and then a layer of
glass mat. Then I alternate glass cloth and mat, one or two
times depending on the thickness. If I've got a low spot,
I'll add more mat on top of that. This new cloth should come
up on the beveled edge around the hole, extending further out
with each piece.
- Let this cure overnight. The surface will cure better if you
paint some PVA (poly-vinyl alcohol, used as a mold release)
on top. Air inhibits the cure.
- Sand the surface smooth. Fiberglass laminate is tough stuff
to sand, and I recommend using a fairly powerful
sander like
my 6-inch random orbit sander.
- If there are any low spots, sand
these roughly and fill with thickened resin, coating with
PVA. After it cures, sand smooth again. Repeat as needed.
- Voila! Now you're ready to paint.
Question: After removing the mast-step plate I noticed that the six screws in this
plate are screwed into the deck. How are they held there, were they screwed
into fresh fiberglass? What kind of holding strength is that? I literally
peeled the plate off with the screws still attached using a screwdriver as
a pry bar. Has anyone ever thru bolted the mast-plate thru the deck? What
do you think about that? Or maybe glassing the bolts in upside down so they
can have nuts screwed on them topsides?(I think Scott Maury "Bill of Rights" did this.) What should I do?
Steve Weingart wrote an article about this and it got included
in the Alberg 30 Maintenance Manual.
FYI: water leaked into the core thru the six bolts in the mast-step
plate, and through the bolts for the hinges for the forward hatch. If I had
rebedded these when I first got the boat in 1996 I probably could have
prevented the majority of the damage. Removing and resteping the mast
several times aggravated the problem. You might want to check your if you
just acquired your boat.
I'll second that notion. I'm in the same boat, so to speak. It's
better to do a bad caulk job than to wait until you can do a better
one. Also, you have to remove things to caulk them. It doesn't
work to put caulk around the edges. I've just recently fallen in
love with Rule elastomeric caulk. I did my chainplates with it, and
so far, I like it better than BoatLife. Save the 5200 for metal
things that you can heat with a torch if you need to remove them.
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Boatowners Mechanical And Electrical Manual
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Other books by Nigel Calder
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