Re: [Paddlewise] Spare the gelcoat -- pros & cons of skin-coat boats

From: Nick Schade <nick_at_guillemot-kayaks.com>
Date: Fri, 6 Jun 2003 09:09:22 -0400
The idea that a thick gelcoat might be structurally useful is one of my 
pet peaves. Gelcoat serves two purposes: one cosmetic, it lets the boat 
have a color; the other is protective, it keeps UV light away from the 
structural part of the layup. It is not strong and does not provide 
good abrasion resistance for its weight.

While making a layup thicker will make it stiffer, additional gelcoat 
is not a good way to do it. While gelcoat may add stiffness, it is 
brittle and will fail more severely than other methods of increasing 
stiffness. While gelcoat does provide some abrasion protection but only 
in a very weight intensive manner. If you really want abrasion 
resistance, the best way is to add more cloth, not more gelcoat. While 
this means that abrasion may cut into the cloth, so what. Glass or 
synthetic cloth added for abrasion resistance will be able to absorb 
abuse while maintaining higher strength better than gelcoat. Additional 
cloth would be stronger and lighter even if it is not as stiff.

The reason for using thick gelcoat is simple: it takes no skill to 
spray in additional gelcoat and it is cheaper than cloth. You don't 
need highly trained (read expensive) labor to do it. A uniform thin 
layer sufficient to provide color and UV protection takes skill and the 
people who can do this are probably better paid over at the local 
autobody shop. More layers of cloth not only costs more in materials, 
it requires more skilled labor to achieve worthwhile results. Thick 
gelcoat is just a way to inexpensively manufacture a kayak that is 
strong enough for most uses.

On Friday, June 6, 2003, at 06:00  AM, Dave Kruger wrote:

> Their justification was that gelcoat provides no
> structural benefit to the boat, and going without it saves 5-8 lbs of
> essentially useless weight. [snip]
> Now I know that finishing the boat's exterior with gelcoat doesn't
> improve the structural rigidity of the craft. [snip]
>
>
Nick Schade

Guillemot Kayaks
824 Thompson St
Glastonbury, CT 06033
USA
Ph/Fx: (860) 659-8847
http://www.guillemot-kayaks.com/

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Received on Fri Jun 06 2003 - 06:09:37 PDT

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