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Added
03/09/2004
Based
on my experience, all cracks were gelcoat cracks only. BUT, under the gelcoat
there is wood!!!
So,
I have decided to fix them all. Here is what I did:
a)
Open the cracks with a small drill bit (Dremel).
b)
Put enough epoxy in the crack to wet all surfaces and seal them.
c)
Fill the remainder of the crack with "Watertight".
d)
Sand
d)
Primer (2 coats)
e)
Sand
f)
Paint (2 coats)
a)
Is the deck of a 22 cored?: Yes.
b)
With plywood, balsa...?: I believe it is marine plywood.
i) Epoxy does not like the sun.
ii) Epoxy by itself is not strong. You need to add fibreglass to
iii) I had already done the bottom of my boat and had some
The
pictures will show you the cracks that have been opened with a
"Dremel" toll, dampened with "Epiglass" and filled with
"Watertight" (picture 1029 and 1042). Then, once it is covered with
primer (Pre-Kote) and paint (Brightside with some matting agent #4317) (pictures
1043 and 1046).
Here
is the link:
http://groups.yahoo.com/group/tanzer/files/Gelcoat%20cracks/
I've
done some similar repairs over the years, and I think you're on the right track.
Compressing the new fiberglass will improve the bond to the underside of
the deck, and reduce the resin to glass ratio.
Also,
try using "release fabric", which will allow the excess resin to flow
out under pressure. In this
application I might use something absorbent (like paper toweling) on the outside
of the release fabric to catch the excess resin that flows out when you compress
the new laminate.
What
you want to do is kind of like vacuum bagging, a common technique for advanced
composite structures. You could put
some kind of airbag or saran-wrapped foam in between the wooden block and the
new laminate, to give an even pressure to the new reinforcement, that squeezes
out excess resin.
The
resins are usually made thin, so they will "wet out" the cloth really
well. If I were doing this I might thicken the resin with just a bit of
colloidal silica. Not too much, or you'll reduce the ability of
the
resin to penetrate the weave of the cloth.
However, a little colloidal silica will go a long way toward reducing the
runniness of the resin.
You
can find some pretty good basic info on West System epoxies at the marine stores
where they are sold, and at http://www.westsystem.com/
Paul Zankel
I've
done this. Forget the wooden block
and mould release. Not needed. Cut
several (2 or 3) pieces of glass cloth or fiberglass tape to the required size.
Place the cloth on waxed paper and wet if out with epoxy - working it in with a
plastic spreader. Be careful not to unravel the threads along the edges too much
as you saturate the cloth. Then simply press the saturated cloth into place.
You can do two or three layers at once.
Pretty easy job.
If
you'd like a "How to ...." book on the subject, try The Fiberglass
Boat Repair Manual by Vaitses
Click
here: Gougeon Brothers, Inc.
The
West System stuff has LOTS of info on fiberglass repair.
I've had great performance with their products, having used most of the
"additives", their resin and all the different hardeners, etc.
One of the most valuable tools I own is a small roller that gets the
fibers in fiberglass mat to "lay down" once its soaked with resin.
Looks like a paint roller, but is about 5/8" diameter, 4" long,
with about a 5" handle. Buy
the aluminum version, which cleans up (for re-use) better and faster.
Why
not drill small holes into the weakened portions of the deck from above and
inject thinned epoxy then fill with appropriate filler of epoxy and microbaloons
or something?
I
hear it works well to seal and solidify the wood.
When
you mentioned injecting resin, do you mean a core between fiberglass,
If
it was a core that was rotting out, I think moisture would be a problem if just
injecting the epoxy. I would bag in the damaged area using plastic or Mylar, get
some kind of vacuum pump set up and let the vacuum suck the moisture out of that
area before I injected the resin. I do a little composite work on aircraft, and
have done very minor repairs (the allowable maintenance manual limit) using
injected resin. You want to make sure it is dry of any moisture. Just my 2
cents.
When
you mentioned injecting resin, do you mean a core between fiberglass, or just
fiberglass plies
I
am of the understanding that thinned epoxy injected into the softened
The
acetone or lacquer thinner chases water from my understanding.
If
my deck was flexible in areas I would certainly drill the holes one inch apart
(as recommended) and allow the area to dry as well as apply heat via heat gun to
assure as dry as possible an area prior to even beginning my repair should the
area of softness be caused by wood rot.
Often
these problems are a result of delamination though and a 5% thinned epoxy is
supposed to be a God send in these cases as opposed to removing and refilling
coring the entire area.
www.epoxyworks.com
has much information on repairs I am told.
I
forgot to comment on this the other day. One
of the liveaboards on my dock had
work done (new deck core, bulkheads, etc.), and the
specialist that did it used isopropyl alcohol (IPA), because it will
readily mix with water, and act as a solvent with wood tars, etc.
Again,
IPA is highly fammable, etc. Here
is the OSHA link to give you all of
the health and safety info. www.osha.gov/SLTC/healthguidelines/isopropylalcohol/recognition.html
After
the IPA dries out, you can start with the thinned epoxy.
In this case, a vacuum bag
technique would good to experiment with!
Last
summer I had to repair a small section of non-skid on the cabin roof that had
been damaged. A buckle had smacked
the area and dented right through to the unlerlying mat. The area was only a couple of square inches but I wanted to
duplicate the pattern so that the repair would appear invisible after painting.
What
I did was to make a plasticine "fence" around a good area that matched
the damaged area for curvature. Using this good section I poured melted candle
wax into my fenced area until I'd made up a good block of a couple of inches
thick. After letting it cool, I
removed the fence and popped off the wax block. Probably best to wait until night or very early in the
morning before the sun can warm the wax. Now
I had an exact mould of the non-skid pattern.
Next, I froze the wax block, cleaned up the damaged area, mixed up some
epoxy, spread it over, and pressed the wax block into it.
Use a weight on the block while the epoxy cures.
If you match the male bumps on the wax to the female dents in the
non-skid then everything lines up perfectly.
Well, in theory anyway. The
mistake I made was to put a bit too much epoxy on the wound.
I got a perfect reproduction but it was about 1/16" too high and I
had to do some tricky carving and sanding.
So
if
using this method you might want to experiment first. I removed the block by melting it away with boiling water but
you should be able to remove it by popping it off.