Boat Building Forum

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Re: Thickness Shear Strength
By:Spidey
Date: 1/23/2001, 12:35 am
In Response To: Re: Glass Kayak (Arlen)

Hi Arlen;

Pardon my abbreviations - I always wonder if it wouldn't be better to just type it out - FG=fiberglass as in local 'fiberglass' suppliers. Sorry . . .

The one essential element plywood provides is a high thickness shear stress. That is, the two layers of glass on opposite sides of the plywood can't easily move "sideways" relative to each other. If they bond well to the wood, the formed composite has good strength in essentially all directions. Foam products would tend to tear rather easily, and a direct impact perpendicular to the composite layer does just that - test the shear strength of the center layer, even though the force is seemingly applied from another direction.

I've noticed that the people who build surfboards on foam blanks (that's most of them) have heavy layups of glass. They're building Corvette bodies over the foam form, and they are heavy as a consequence. The honeycomb stuff is very light, with a loose unidirectional glass fiber bonded to the flat surfaces that you lay glass cloth over and bond to. It has the characteristic of being structurally rigid in thickness shear mode, mimicking plywood, at 1/3 the weight.

Darn - I've talked myself into it - I'm gonna buy a honeycomb sheet and play around!

Best Regards, Spidey

Messages In This Thread

Glass Kayak
Johnnie -- 1/21/2001, 1:32 pm
Not suitable for scottish paddlers! :) *NM*
Marcelo -- 1/24/2001, 11:06 am
Re: Not Fiberglass Thank God!
George Cushing -- 1/23/2001, 2:33 pm
Re: Glass Kayak
Ken Brunton -- 1/23/2001, 2:30 pm
Re: Check this out, Lexan kayak from Innovex Corp
Grant Goltz -- 1/23/2001, 12:23 pm
Re: Glass Kayak
Johnnie -- 1/22/2001, 10:29 pm
Re: Glass Kayak
David Dick -- 1/23/2001, 6:57 am
Re: Glass Kayak
Don -- 1/22/2001, 10:16 pm
Re: Makes me wonder
Shawn Baker -- 1/23/2001, 10:44 am
Re: Makes me wonder
George Cushing -- 1/24/2001, 6:11 am
Re: Aren't Trees Amazing?
Shawn Baker -- 1/24/2001, 10:22 am
Re: Aren't Trees Amazing?
Grant Goltz -- 1/24/2001, 12:36 pm
Re: Aren't Trees Amazing?
Shawn Baker -- 1/24/2001, 12:55 pm
Re: Strip-deck C
Grant Goltz -- 1/25/2001, 12:49 pm
Re: Makes me wonder
Don -- 1/24/2001, 2:35 am
Re: Heat Treating Plastic
Shawn Baker -- 1/24/2001, 10:17 am
Re: Glass Kayak
John Schroeder -- 1/22/2001, 9:58 pm
Re: Polycarbonate *Pic*
Shawn Baker -- 1/22/2001, 11:29 am
Re: Polycarbonate
Lee -- 1/23/2001, 1:06 am
Re: Reading Material
Shawn Baker -- 1/23/2001, 10:31 am
Methyl Methacrylate
Pete Rudie -- 1/22/2001, 4:39 pm
Re: Help Pete!
George Cushing -- 1/23/2001, 3:00 pm
Re: Help Pete!
Pete Rudie -- 1/24/2001, 1:05 am
Re: Allright Smarty Pants!
George Cushing -- 1/23/2001, 2:56 pm
I wonder
mike allen -- 1/22/2001, 5:31 pm
Re: I wonder VACUUM FORMING
Eric Schade (shearwater boats) -- 1/22/2001, 7:30 pm
Re: I wonder VACUUM FORMING
John Monfoe -- 1/23/2001, 6:46 am
Re: Big Aluminum Billet
Spidey -- 1/23/2001, 1:31 am
Re: I wonder VACUUM FORMING
mike allen -- 1/22/2001, 8:06 pm
Re: Glass Kayak
Spidey -- 1/22/2001, 1:14 am
Re: Glass Kayak
Arlen -- 1/22/2001, 11:32 pm
Re: Thickness Shear Strength
Spidey -- 1/23/2001, 12:35 am
Re: Thickness Shear Strength
Ken Brunton -- 1/23/2001, 2:16 pm
Re: Glass Kayak
Victor lapostolle -- 1/22/2001, 1:54 am
Re: Glass Kayak
John Monfoe -- 1/22/2001, 6:17 am
Re: Both Glass Kayaks! :)
Spidey -- 1/23/2001, 12:16 am
Lexan Kayak
Paul G. Jacobson -- 1/21/2001, 11:33 pm
Re: lots of suntan lotions
Tony -- 1/22/2001, 6:48 pm
Re: Glass Kayak
daren -- 1/21/2001, 10:14 pm
Re: Glass Kayak
David Hanson -- 1/22/2001, 12:29 pm
Re: Glass Kayak
Jon -- 1/21/2001, 7:54 pm
Re: Glass Kayak
tom preska -- 1/21/2001, 9:38 pm
Re: Glass Kayak
Johnnie -- 1/21/2001, 10:13 pm
Re: Glass Kayak
David Dick -- 1/21/2001, 11:25 pm