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From: Dave Kruger <kdruger_at_pacifier.com>
subject: [Paddlewise] Restoring Gel Coat
Date: Sun, 14 Dec 2003 19:42:55 -0800
Ten seasons of use on my Wind Dancer eroded the gel coat badly at the stern
and some at the bow ...  the effects of sand and barnacles.

So, I replaced the eroded areas best I could using one of those gel coat kits
from the marine supply store.  Matching the subtle off white tint of the hull
was one chore (failed on the bow; close on the stern), but the main
difficulty was making the gel coat conform to a rounded cross section at the
stern, where the keel forms a compound curve as it rounds to the vertical.
If I could just slop the stuff on and sand back to the surface I want, it
would be easy, but gel coat won't cure unless air is excluded.  That demands
some close, form-fitting plastic film.  I used thick poly film and masking
tape anchors every couple inches around the perimeter of the plastic.

I was unable to make my film tight while simultaneously leaving much gel coat
underneath.  The result is some replacement at the stern, but not enough for
another ten years.

So, is there a better method?  Or, a better repair kit than the marine supply
store kits?  I'm gonna live with this job until the gel coat is gone again,
but for next time ...

Thanks.

--
Dave Kruger
Astoria, OR
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From: Michael Neverdosky <mikenever_at_earthlink.net>
subject: Re: [Paddlewise] Restoring Gel Coat
Date: Sun, 14 Dec 2003 23:20:26 -0500
Most pros don't even try to patch any large areas of gel coat.
They just go to a paint finish.
There are some really nice LP (linear polyurethane) paints out there
that are very tough and give a fantastic finish.

michael

Dave Kruger wrote:
> 
> Ten seasons of use on my Wind Dancer eroded the gel coat badly at the stern
> and some at the bow ...  the effects of sand and barnacles.

> 
> So, is there a better method?  Or, a better repair kit than the marine supply
> store kits?  I'm gonna live with this job until the gel coat is gone again,
> but for next time ...
> 
> Thanks.
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From: Michael Daly <michaeldaly_at_rogers.com>
subject: Re: [Paddlewise] Restoring Gel Coat
Date: Sun, 14 Dec 2003 23:35:33 -0500
On 14 Dec 2003 at 19:42, Dave Kruger wrote:

> So, is there a better method?  Or, a better repair kit than the marine
> supply store kits?  I'm gonna live with this job until the gel coat is
> gone again, but for next time ...

A few options - 

You could add a thickener (aka thixotrope) to increase the stiffness  
of the gelcoat (up to peanut butter consistency or stiffer) and 
minimize the film's squeezing out the stuff.  If you used cabosil 
(colloidial silica) it would also resist wear-and-tear to a greater 
extent than plain gelcoat.  However, it also resists sanding, so if 
the shape isn't quite right, you'll have more work to do to correct 
it.

You could loosely apply a finer plastic film, like saran wrap, and 
then not have pressure squeezing out the gel coat.  The finish will 
not be smooth, so post-cure sanding would be required.  This with a 
thickener would also be a good combination.

You could get a gelcoat that contains wax.  The wax rises to the 
surface and excludes air - no plastic film needed.  The problem with 
this stuff is that it's not quite as strong as waxless gelcoat.  Your 
surface will also not be as smooth as with a release film.

You could skip the gelcoat and put on a fiberglass rub strip with 
epoxy.  If it is the keel, I wouldn't worry much about sun exposure 
and leave it bare.  A bit of UV filtering exterior polyurethane can 
be painted on for UV protection otherwise.  This would be a teensy 
bit heavier but somewhat stronger.  You wouldn't have to worry about 
abrasion of the glass until it gets through the rub strip.  As it 
wears, just keep adding polyurethane - just like the S&G kayakers do.

Finally, you could take your chances and leave the gelcoat uncovered. 
This will create a layer of gelcoat on the surface that doesn't cure. 
If you're lucky, the uncured layer won't be too thick and you can 
sand/scrape it off.  Just glop on more than you need and when the 
uncured is removed, the remainder will be close to the right shape.  
I'm not sure if this will prevent all curing with some gelcoats, but 
I know that the one time I did this, only a surface layer was 
uncured.  I'd consider this the least desirable option.

I bet there are other methods, but I can't think of them now.

Mike
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From: Steve Holtzman <sh_at_actglobal.net>
subject: RE: [Paddlewise] Restoring Gel Coat
Date: Sun, 14 Dec 2003 20:41:55 -0800
Dave Kruger said:



> Subject: [Paddlewise] Restoring Gel Coat

> So, is there a better method?  Or, a better repair kit than

> the marine supply store kits?  I'm gonna live with this job

> until the gel coat is gone again, but for next time ...

>



Dave,



Both Derek Hutchinson and the repair shop I brought my boat to for some
FG repairs, suggested using MarineTex epoxy instead of gelcoat. It is
stronger and lasts longer---just not quite as pretty, but since the keel
is underwater, the only time it is noticed is when the boat's out of the
water.



Steve Holtzman

Southern CA




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From: <SNStone_at_aol.com>
subject: Re: [Paddlewise] Restoring Gel Coat
Date: Mon, 15 Dec 2003 06:07:49 EST
If it were me I would add a keel strip. This is explained at:

http://www.atlantickayaktours.com/Pages/ExpertCenter/Repairs/KeelStrip/Keel-St
rip-1.shtml

good luck
So, is there a better method?  Or, a better repair kit than the marine supply
store kits?  I'm gonna live with this job until the gel coat is gone again,
but for next time ...
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From: Dave Kruger <kdruger_at_pacifier.com>
subject: Re: [Paddlewise] Restoring Gel Coat
Date: Tue, 16 Dec 2003 08:58:46 -0800
Thanks to the many who responded on the list and offlist.

I decided to let my botched job wear down until the time when it needs doing
again ... when I will have the arsenal of suggestions to guide me at a better
job.

My goal was to get some near-color gel coat down on the bare FRP matrix to
sacrifice to the sand and rock gods, and I did that.  for me, gel coat on the
keel is just there to protect the substructure.  I don't really care much
what it looks like.

Next time I'll search out a better source of the gel coat, for starters.

Just for the record, I found fairing the new gel coat into the surrounding
contours easy.  I think it is a little softer than the old, wizened stuff
underlying.  After whacking away with the trusted cabinet scraper to get the
gross stuff out of the way, a few hits with 220, then 400, then 600 grit (all
wet sanded) gave me something very close to a matte finish.  Then I converted
my orbital sander pad to a polishing pad with some thickish T-shirt material
(2 layers) and finished it off with some (supposedly) 1500 grit polishing
compound from 3M.  Worked like a dream.  If I get really bored (or anal) this
winter I might touch up some of the deck rash on this boat.  Eleven seasons
of paddle pounding has left a few areas pretty raw, but still rich in gel
coat to polish.  A Wind Dancer is never a fast boat, but this one has been
very kind to me, and I feel I owe it a little TLC.

--
Dave Kruger
Astoria, OR
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From: <HTERVORT_at_aol.com>
subject: Re: [Paddlewise] Restoring Gel Coat
Date: Tue, 16 Dec 2003 17:53:14 EST
In a message dated 12/14/2003 7:43:57 PM Pacific Standard Time, 
kdruger_at_pacifier.com writes:
I was unable to make my film tight while simultaneously leaving much gel coat
underneath.  The result is some replacement at the stern, but not enough for
another ten years.

So, is there a better method?  
For an easily-controlled airproof seal, spray or brush on PVA (poly vinyl 
acetate).  This is a green liquid that dries over the repair and blocks air as 
the gelcoat cures.  It then washes off with water.  Should be available wherever 
you buy fiberglass supplies.

Harold
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From: Michael Daly <michaeldaly_at_rogers.com>
subject: Re: [Paddlewise] Restoring Gel Coat
Date: Wed, 17 Dec 2003 00:17:51 -0500
On 16 Dec 2003 at 17:53, HTERVORT_at_aol.com wrote:

> For an easily-controlled airproof seal, spray or brush on PVA (poly
> vinyl acetate). 

That should be polyvinyl alcohol.  There are two different PVAs and 
they get confused a lot.  Both are common.  PV Acetate is used in 
glues and such; PV alcohol is used in artificial tears and other 
opthalmic solutions.  

Mike
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From: Michael Daly <michaeldaly_at_rogers.com>
subject: Re: [Paddlewise] Restoring Gel Coat
Date: Wed, 17 Dec 2003 00:17:51 -0500
On 16 Dec 2003 at 17:53, HTERVORT_at_aol.com wrote:

> For an easily-controlled airproof seal, spray or brush on PVA (poly
> vinyl acetate). 

That should be polyvinyl alcohol.  There are two different PVAs and 
they get confused a lot.  Both are common.  PV Acetate is used in 
glues and such; PV alcohol is used in artificial tears and other 
opthalmic solutions.  

Mike
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From: Doug Lloyd <dalloyd_at_telus.net>
subject: RE: [Paddlewise] Restoring Gel Coat
Date: Tue, 16 Dec 2003 18:32:23 -0800
Steve H. posted (snip):
>suggested using MarineTex epoxy instead of gelcoat. It is stronger and
lasts longer---just not quite as pretty, but since the keel is underwater,
the only time it is noticed is when the boat's out of the
water.<

I'd agree here. Sure, you can make some up yourself, but unless you have all
the ingredients and the supplies are fresh, the MarineTex is a good option
despite the cost. If cosmetics are really important to you, then fork out
the bucks for a professional repair. Just don't get ripped off. Some shops
charge way too much.*

*There was an incident at Port Renfrew in the surf recently. Someone in a
ply kit kayak (you know the kind, with the really sharp, pointy bow)
punctured someone's new Kevlar kayak. The shop doing the repairs really took
the person for a ride (the paddler did get some money back in the end).

Doug Lloyd
Victoria BC (where the weather was nuking again today)
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From: <HTERVORT_at_aol.com>
subject: Re: [Paddlewise] Restoring Gel Coat
Date: Thu, 18 Dec 2003 11:22:11 EST
Yes, thank you.  I believe that's right.

I have a jug of it at work that's missing the label, so PVA is all I really 
know it by.
Standard stuff as a release agent and to block oxygen from during gelcoat.

As far as brushing it on, I sometimes do that after letting the gelcoat 
become rubbery.  It is much better to spray it on, but the PVA has a nasty habit of 
plugging up spray bottle nozzles and I'm usually working under too tight a 
schedule to want to take the time to clean things up.


Harold
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