Re: [Paddlewise] Hull Repairs

Doug,

I haven't yet done any repairs on my glass kayak -- this is the first
composite kayak I have owned.  But I've done lots of fiberglass repairs on
other kinds of boats, and I have some ideas regarding how I will make
repairs on the kayak, once they become necessary.

> 1. Deep hull scratches  -  I normally use a gel coat filler [snip]

If I was certain of a close color match, I might do this.  But I much prefer
plain old epoxy with fillers.  I use Raka epoxy for most of what I do, and
sometimes use West System also.  I mostly use West fillers -- they make a
good selection of fillers that have been carefully developed for particular
uses.  For something like this, I'd probably use one of the light colored,
non-structural low-density fillers (like 406, the colloidal silica).  For
color, I'd use some of those little tubes of coloring agents made by
Evercoat that you can get at any chain "chandlery" and mix them up until I
got as close a match as I could.  The sequence is: get the coloring mixed as
close as possible in a little plastic bowl; then mix the epoxy separately,
then mix in the filler, then mix in the color.  Then apply very sparingly.
I'd probably put masking tape around the area to be filled so as to minimize
overflow.  I think this makes an overall better repair than mere "gel coat
filler."

> 2. Excessive keel-line wear (usually near the stern)  -   I will either
> use thick multiple layers of gel coat fill (thick stuff), or add cloth
> impregnated with resin, then perhaps top off with gel coat fill.

I would do this mostly the same as I would do hull scratches, except that I
would use the cloth as well, depending on the severity of the wear.  Again,
I just don't really like working with polyester, and I think epoxy makes a
much stronger repair.  If I were using a filler, I'd go with one of the
structural West fillers, probably 404.  I might even go with graphite
powder.  Depending on the repair, I might use fiberglass "matt" rather than
cloth, or perhaps a heavier cloth, like 9 oz.  By the way, for those who
haven't done much of this, it really pays to use the "tape" instead of just
getting sheets of the cloth.  Raka sells tape in various widths and weights,
as do other companies (System Three, Mass, etc).  You get a much cleaner
result, and you don't have to worry about all those loose fibers on the
edges.  As for other methods, I do remember someone here saying they added a
very small "keel" on the bottom to protect against scratches and that it had
an unexpected (but good) result on performance.  If I were doing this (which
I might consider) I would probably just do a build-up of fiberglass/epoxy,
but another method might be to mount a bronze strip along the bottom.  This
is often done on dinghies, and you can get the stuff pretty much anywhere.

> 5. If you were attending a seminar, what would you like to see
> covered/explained/demonstrated?

I have been working with fiberglass for so long most of it is second nature
to me.  I sometimes have to work to remind myself of how little the average
person knows about these products -- even the average boater.  Even the
average do-it-yourself boater.  So whenever I'm giving instruction on this
kind of thing I try to give a thorough lesson in what the products are and
how they work.  As in: "there are two types of resins, polyester and
epoxy..." etc.  There are countless little questions that come up -- "does
epoxy stick to [this or that]; is it waterproof or do you have to put
gelcoat on?" etc.  So I would think this would be a good component of your
lecture.  A good grounding in how the products work.  Perhaps some reference
to some of the good books that are out there.  A couple of the books I like
are:

Jack Wiley, "Modifying Fiberglass Boats" (this is a classic, to the extent
such a thing can exist in this little world of boat repair)

Jack Wiley, "The Fiberglass Repair and Construction Handbook"

Allan Vaitses, "The Fiberglass Boat Repair Manual" (a more "modern"
"classic")

Don Casey, "Sailboat Refinishing" (very basic stuff, good beginner book)

Paul & Marya Butler, "Fine Boat Finishes" (this is an excellent little book)

Obviously, a lot of this material is directed toward sailboaters.  But much
of the content is more general and would apply to composite boats of any
type.  Given the relative newness of composite kayaks, I think these books
are likely to contain the best info out there on the subject.  By the way,
another little book that is really excellent is "Runabout Rennovation" by
Jim Anderson.  As much as I dislike those noisey little stinkpotters, the
book is surprisingly good and contains much general information about
fiberglass repair and refinishing.

So, there's a few thoughts for ya, Doug.  Anything else I can do please let
me know.

Mark Lane


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