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From: John Kirk-Anderson <jka_at_netaccess.co.nz>
subject: [Paddlewise] Fibreglass - thickness versus strength
Date: Mon, 04 Jul 2005 22:31:42 +1200
I have built a new rudder pedal and foot-pump assembly for my Nordkapp, and
I was very pleased with it until I weighed it. I'm too embarrassed to admit
how obese it is, but a weight-loss program using cosmetic surgery has
started. It is made from fibreglass, and I have laid it up very thick. It is
easily the strongest part of my whole kayak.

Now I need advice.

Am I better to reduce the thickness, by cutting back with a Dremel tool, or
to drill holes through it in strategic places? If I do, am I better to use
fewer, large holes, or more small ones?

I'm keen on the hole drilling route (I've already started), as it will be
easier, but I know I will quickly reach a point of diminishing returns.

At some stage I will start again and use core-mat, Carbon/Kevlar and better
design, but for now I want the easiest route.

Any suggestions?

-- 
John Kirk-Anderson
Banks Peninsula
NEW ZEALAND
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From: Michael Daly <mikedaly_at_magma.ca>
subject: Re: [Paddlewise] Fibreglass - thickness versus strength
Date: Mon, 04 Jul 2005 09:24:54 -0400
On 4 Jul 2005 at 22:31, John Kirk-Anderson wrote:

> Am I better to reduce the thickness, by cutting back with a Dremel
> tool, or to drill holes through it in strategic places? If I do, am I
> better to use fewer, large holes, or more small ones?

I'd reserve comment until I saw what the thing looked like.  In 
general, drilling holes is not a very effective way to reduce weight.
The strength reduction is often greater than the weight reduction.
One hole in the wrong place can do a lot of strength reduction.

Can you post a couple of photos on a web site?

Mike
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