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From: Doug Lloyd <douglloyd_at_shaw.ca>
subject: [Paddlewise] Kayak Marine Foam Construction
Date: Thu, 15 Mar 2007 21:02:38 -0700
Why are not more kayaks made with foam core/glass construction?

http://images.businessweek.com/ss/06/08/kayak/source/5.htm

Doug Lloyd
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From: Robert Livingston <bearboat2_at_comcast.net>
subject: Re: [Paddlewise] Kayak Marine Foam Construction
Date: Fri, 16 Mar 2007 01:04:51 -0700
I think just because it is too heavy.

You need a certain amount of cloth and resin on both sides of the  
foam to resist punctures and dents. By the time you have gotten that  
far, you have basically laid down enough resin and glass to be strong  
and stiff enough to be a kayak without a foam core.

The reason is that kayaks are small. The glass does not have to be  
that thick to maintain a kayak shape.

Adding the foam just adds weight.

If you are making a big boat without foam then you might lay down  
enough glass to be reasonably puncture resistant bit it is not stiff  
enough. So you have to lay down a lot of glass just to get thick  
enough to be adequately stiff. In this environment, the foam can save  
weight because it boosts the thickness without adding so much weight.

You can see a little bit of foam being using in big kayaks like  
doubles in limited areas such as the flat bottom in the wide part of  
the boat because of the demand for stiffness.




On Mar 15, 2007, at 9:02 PM, Doug Lloyd wrote:

> Why are not more kayaks made with foam core/glass construction?
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From: Geoff <geoff_at_texaskilonewton.com>
subject: Re: [Paddlewise] Kayak Marine Foam Construction
Date: Sun, 18 Mar 2007 16:14:49 -0700
On Fri, 2007-03-16 at 01:04 -0700, Robert Livingston wrote:
> I think just because it is too heavy.

I don't know about that.  I just bought a brand new Mega Megatron Surf
Kayak.  It's got a thin foam core to it, kevlar/graphite on the deck and
graphite on the hull.  It's anything but heavy.  


Oh, and it SCREAMS on a wave.   
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From: Doug Lloyd <douglloyd_at_shaw.ca>
subject: Re: [Paddlewise] Kayak Marine Foam Construction
Date: Fri, 16 Mar 2007 06:26:48 -0700
That would make sense. Though, the kayak manufactures using this technique 
(sandwiched into a layer as opposed to high-tech thermoform) make strength 
and lightweight claims, along with added stiffness (better strength, being 
the aspect that caught my eye).

I do like the prospect of more manufactures using infusion technology 
though. Done correctly (as with some of the Point 65 Swedish kayaks), the 
results appear aesthetically faultless and overall, very durable for the 
relative weight in their more expensive lines using Kevlar-combined fabrics.

I'm still toying with the idea of reproducing my own kayak in a high-tech, 
stronger fabric. People have done stranger things:

http://www.thag-o-mizer.net/infusion_page1.html

Doug Lloyd

>I think just because it is too heavy.
>
> You need a certain amount of cloth and resin on both sides of the
> foam to resist punctures and dents. By the time you have gotten that
> far, you have basically laid down enough resin and glass to be strong
> and stiff enough to be a kayak without a foam core.
>
> The reason is that kayaks are small. The glass does not have to be
> that thick to maintain a kayak shape.
>
> Adding the foam just adds weight.
>
> If you are making a big boat without foam then you might lay down
> enough glass to be reasonably puncture resistant bit it is not stiff
> enough. So you have to lay down a lot of glass just to get thick
> enough to be adequately stiff. In this environment, the foam can save
> weight because it boosts the thickness without adding so much weight.
>
> You can see a little bit of foam being using in big kayaks like
> doubles in limited areas such as the flat bottom in the wide part of
> the boat because of the demand for stiffness.
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From: <wsmith16_at_charter.net>
subject: Re: [Paddlewise] Kayak Marine Foam Construction
Date: Fri, 16 Mar 2007 5:59:27 -0800
A paddling bud of mine built a foam-core Outer Island last year at home. He did a really nice job, considering he doesn't have the equipment to vaccuum-bag it. It's a tough boat, but it weighs even more than an Explorer. He said if he could vaccuum-bag it, it would likely be a great layup to use, because it would be just as tough, and quite a bit lighter.


--
Wayne Smith
wsmith16_at_charter.net

Check out my website!  http://webpages.charter.net/wsmith16/home.html

---- Doug Lloyd <douglloyd_at_shaw.ca> wrote: 
> That would make sense. Though, the kayak manufactures using this technique 
> (sandwiched into a layer as opposed to high-tech thermoform) make strength 
> and lightweight claims, along with added stiffness (better strength, being 
> the aspect that caught my eye).
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