On Thu, 19 Feb 2004 01:31:54 -0330, "VK1NF" wrote:

Rick Hayes here. Since Alex mentioned my e-mail to him, I thought I'd post
it for the benefit of others.
Several repair strategies are possible - which I'd use
would depend on two things - the actual nature/shape of the crack itself,
and secondly how important the cosmetic finish is to you.
If the crack simply radiates in widely separated lines, you have the option
of routing out the cracks - maybe using a Dremel tool (very carefully) with
a fine bit or stone - then filling the resulting trough with either a
thickened epoxy paste (silica filler) or a two part epoxy putty. Allow to
cure, then sand off to fair the repair. Paint/gelcoat if appearance is
important.
If the damage is too extensive for routing out - lots of concentric circles
of cracks, for example - you can sand out the gelcoat from the entire area,
then rebuild it using thickened epoxy fillers and perhaps a top layer of
gelcoat. I don't bother with gelcoat - find that thickened epoxy fillers
work just as well. Of course, it leaves an off-colour patch, and it can be
difficult to get it faired in really well. But then, I tend to worry a lot
more about 'solid' than I do about 'pretty'.
A third option, although a rather barbaric one, is to simply whack a
fibreglass cloth/epoxy patch over the area - then fair in the edges and the
weave of the cloth as well as you can with thickened epoxy, and sand to
fair. Isn't pretty, but it'd at least keep water out of the laminate.
Finally, if the boat is stored outdoors, and freeze/thaw is a concern in the
short term - I'd be inclined to temporarily cover over the cracks with
TuxckTape until I got a chance to do the repair - the tape will leave a
sticky
residue, but hey, better a minor cleaning job than laminate problems.
Hope this helps.
Regards,
Rick

The second option here is the best.

The latter is cheap and nasty and the former creates a weak repair.

Fibreglass is a rare bast that can actually be repaired to original
strength. feather back the damaged area to the fibreglass - carefully,
then lay on some matt and resin, sand, fill and sand, and then recoat
with gelcoat.

Two pack fillers are NOT waterproof which is why car bodies repaires
with filler end up with rust around the edges just before the filing
falls out :-)

The middle option is the hardest work but the best solution.

Ewan Scott