My NDK explorer took a smack when I was not looking.
I have a star crack about 2 feet long and 6 inches wide just under the
water line. There is no dent, just cracked jell coat. Any idea how to
fix this or stop water permeating into the glass underneath and
causing delamination in the freeze thaw cycle?
Thanks
Alex

Alex McGruer wrote:
My NDK explorer took a smack when I was not looking.
I have a star crack about 2 feet long and 6 inches wide just under the
water line. There is no dent, just cracked jell coat. Any idea how to
fix this or stop water permeating into the glass underneath and
causing delamination in the freeze thaw cycle?

I'd use gel coat filler, which your friendly neighbourhood ship's
chandler should have. The stuff I got was "Plastic Padding" and came in
hardener/goop two part. Mix together, apply along the wound after
giving it a rough sand to key it first and then once it's dry sand,
sand, sand. Start with rougher gauges and gradually move to finer, end
up using a polishing paste for best results.
Worked okay on my Selkie, and I'm hardly an expert handyman.

But since you're going to someone who knows about it to get the goop to
start with, have a word with them about it anyway. A couple of times
I've gone to get first aid stuff for minor repairs and been directed to
a much more suitable idea after discussing it with the chaps the they
do fibreglass for a living and know a helluva lot more about it than I do!

Pete.
--
Peter Clinch University of Dundee
Tel 44 1382 660111 ext. 33637 Medical Physics, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

Peter Clinch wrote in message ...
Alex McGruer wrote:
My NDK explorer took a smack when I was not looking.
I have a star crack about 2 feet long and 6 inches wide just under the
water line. There is no dent, just cracked jell coat. Any idea how to
fix this or stop water permeating into the glass underneath and
causing delamination in the freeze thaw cycle?

I'd use gel coat filler, which your friendly neighbourhood ship's
chandler should have. The stuff I got was "Plastic Padding" and came in
hardener/goop two part. Mix together, apply along the wound after
giving it a rough sand to key it first and then once it's dry sand,
sand, sand. Start with rougher gauges and gradually move to finer, end
up using a polishing paste for best results.
Worked okay on my Selkie, and I'm hardly an expert handyman.

But since you're going to someone who knows about it to get the goop to
start with, have a word with them about it anyway. A couple of times
I've gone to get first aid stuff for minor repairs and been directed to
a much more suitable idea after discussing it with the chaps the they
do fibreglass for a living and know a helluva lot more about it than I do!

Pete.


Thank you Peter
Richard Hayes I think came up with the rest of the recipe. A Dremmel
Tool with a fine stone to rout out the cracks and fille ach crack.
I am going to take your advice and the little I know and see if i can
find a garage to beg or borrow and have at it.
I went to an auto body place to see what they could do. $1,000 Cdn.
ouch. Now it would look like new but I am not woried about that right
now.
Thanks again Richard and Peter.

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

--
"You Shouldn't Have Joined
If You Can't Take A Joke"

Royal Navy Axiom
replace vk1nf with rhayes to reply



---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.592 / Virus Database: 375 - Release Date: 2/18/04

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

Ewan Scott wrote:

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 :-)

Some may not be, some I think are. The one I used specifies boat
repairs as one of its jobs and was sold to me on recommendation by a
specialist fibreglass boat builder. Mileage varies...

Pete.
--
Peter Clinch University of Dundee
Tel 44 1382 660111 ext. 33637 Medical Physics, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/