Re: [Paddlewise] Restoring Gel Coat

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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