Re: [Paddlewise] NDK layups...

> >Ever thought about grinding way the gelcoat [gasp! gasp!] and adding a
new
> >layer of gel?
I noticed this thread but hadn't had time to focus on it.  The problem of
spiderwebbing or gelcoat cracking is very common in older sailboats, and
I've dealt with it a great deal.  Most of the time it is at stress points,
often where there is a bulkhead or joint beneath the spot.  Sometimes it is
from an impact of some sort.  It's very very common on not usually of much
real significance, other than aesthetic.

> I've wondered if [replacing the gelcoat] would be a good solution. I have
no experience with this sort > of thing, and I've never worked with
fiberglass.

Replacing gelcoat is not really a great solution, IMO.  Gelcoat is usually
applied inside a mold with the glass applied over it.  Doing it after the
fact, so to speak, is not the same thing.  It requires quite a lot of work,
buffing etc.  The more typical (and more practical) solution is simply to
re-"paint" the surface.  I use the word paint in quotes because what I
prefer to use is not technically considered a paint.  What I refer to is the
two-part poly coatings.  These are sold in marine supply stores -- I often
use Interlux Interthane Plus.  They are also common among airplane types.  I
usually use a 2 part epoxy primer first.  Sometimes the primer alone will be
enough to fill the cracks; sometimes you need to mix up an epoxy putting and
cover them.  The process is somewhat painstaking, but not particularly
difficult, really.  Use good masks at all times, especially when working
with the 2 part poly.

> >Are these cracks along a seam?  Do you see a difference in glass
thickness
> >on the underside of the hull/crack?
>
> *One* of the cracks stems from (or extends into?) the seam tape. Is this
significant,

It probably is some indication of the source of the stress.  Is it near a
bulkhead?  I would definitely reinforce the seam where the cracking is with
a reasonable amount of fiberglass tape and epoxy before attempting any
repairs on the outside.

These are just a few thoughts -- without having seen it it's difficult to be
sure what is going on.  If I can be of further assistance let me know.

Mark Lane

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