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Re: Material: Light weight layup
By:Mark
Date: 12/5/2002, 6:53 pm
In Response To: Material: Light weight layup (Larry C.)

OK... I have no kayak building experience, but I have built boats and more significant, LOTS of RC airplane building. In planes, weight is crucial. And the weight you can eliminate with eglass is in the resin. The lighter cloths will require less fill coat, but THE way to do it when a fill coat is not required is with vacuum bagging! Bagging is also the best way to completely eliminate the cloth floating off the substrate. If I were seriously trying for a light weight boat, I would seriously consider vacuum baggin the inside of the hull, and not fill coating it. I think, with the outside already glassed, bagging the inside wouldn't be too too tricky.

The other thing to consider for really light boats, is using balsa for parts of the hull! Balsa is a surprisingly strong material. The grain isn't pronounced but it wouldn't look bad with decorative strips. And it would sure be easy to shape/work. The density is well below the other woods being used so I'm sure it would save weight. It would be pricy though.

On the kevlar issue... I've built airplane wing structures and broken them in controlled situations (weights on a wing on saw horses) to find out what layup works best. In ALL cases I've tried, the failure mode was crushing the substrate and/or surface in compression, NOT tearing the surface in tension. I have not done this with wood cores, but with wood reinforced foam cores. It may be worth a try for someone out there to build a test panel, and break it (slowly)! see if it fails first in compression or tension. Based on what I've seen, I think the kevlar isn't going to provide much gain in actual breaking strength, because its main advantage is in tension, and the failure mode will probably be in compression.

Just my 2Cents on an already stale topic...

Messages In This Thread

Material: Light weight layup
Larry C. -- 12/5/2002, 12:30 pm
I'm building one too
Jack Sanderson -- 12/6/2002, 2:49 pm
Re: I'm building one too
Larry C. -- 12/7/2002, 8:17 am
Thanks, everyone *NM*
Larry C. -- 12/7/2002, 8:22 am
Re: Material: Light weight layup
Paul G. Jacobson -- 12/6/2002, 1:08 am
Re: Material: Light weight layup
Jeff The Tall -- 12/6/2002, 3:18 pm
Re: Material: Light weight layup
Mike Loriz -- 12/6/2002, 1:11 pm
Re: Material: Light weight layup
Don Lucas -- 12/6/2002, 11:04 am
Re: Material: Light weight layup - Bulkheads
KenB -- 12/6/2002, 1:02 pm
Re: Material: Light weight layup - Bulkheads
Shawn Baker -- 12/6/2002, 4:44 pm
Re: Material: Light weight layup
Mark -- 12/5/2002, 6:53 pm
Re: Material: Light weight layup
Mike Loriz -- 12/6/2002, 12:57 pm
Re: Material: Light weight layup *Pic*
Chip Sandresky -- 12/5/2002, 7:25 pm
Budget, weaker pressure "vacuum bagging"
Paul G. Jacobson -- 12/6/2002, 10:42 pm
Re: vac bagging
Mark -- 12/6/2002, 10:15 am
Re: vac bagging
Jeff The Tall -- 12/6/2002, 2:48 pm
Re: vac bagging
Shawn Baker -- 12/6/2002, 6:16 pm
Re: vac bagging
Chip Sandresky -- 12/6/2002, 5:25 pm
Re: vac bagging
Mark -- 12/7/2002, 12:58 pm
Re: vac bagging *LINK*
david schneider -- 12/14/2002, 12:03 pm
Re: vac bagging
Roger Nuffer -- 12/14/2002, 12:58 pm
Re: vac bagging *LINK*
david schneider -- 12/14/2002, 4:25 pm
Re: vac bagging
Shawn Baker -- 12/6/2002, 6:20 pm
Re: vac bagging
Mark -- 12/6/2002, 4:52 pm
Re: vac bagging
Jeff The Tall -- 12/9/2002, 4:52 pm
Re: vac bagging - OK for Wiki?
Shawn Baker -- 12/6/2002, 6:19 pm
OT: thanks for the pic
Larry -- 12/5/2002, 10:50 pm
Re: Material: Light weight layup
Scott Fitzgerrell -- 12/5/2002, 3:18 pm
Re: Material: Light weight layup
Rob Macks -- 12/5/2002, 4:03 pm
Re: Material: Light weight layup
Shawn Baker -- 12/5/2002, 4:25 pm
Re: Material: Light weight layup
Mike Loriz -- 12/5/2002, 2:37 pm
Re: Material: Light weight layup
Jim Kozel -- 12/5/2002, 3:11 pm
Re: Material: Light weight layup
mike loriz -- 12/5/2002, 5:09 pm
Re: Material: Light weight layup
Jim Kozel -- 12/7/2002, 9:41 am
Re: Material: Light weight layup
Mike Loriz -- 12/10/2002, 7:33 pm
Re: Material: Light weight layup
Fred -- 12/7/2002, 10:08 am
Re: Material: Light weight layup
Jim Kozel -- 12/7/2002, 11:32 am
Re: Material: Light weight layup
KenB -- 12/5/2002, 2:29 pm
Re: Material: Light weight layup
LeeG -- 12/6/2002, 2:28 pm
Re: Material: Light weight layup
Chip Sandresky -- 12/5/2002, 3:12 pm
Re: Material: Light weight layup
Shawn Baker -- 12/5/2002, 2:24 pm
Out there.
Myrl Tanton -- 12/5/2002, 12:44 pm
Re: Out there.
Ross Sieber -- 12/5/2002, 1:49 pm
RE: Boom! - are you sure?
Myrl Tanton -- 12/5/2002, 3:50 pm
Re: RE: Boom! - are you sure?
Larry -- 12/5/2002, 10:34 pm
Re: Float bag contents
Shawn Baker -- 12/5/2002, 4:23 pm
Re: COTFLGUOAHAHA
Ross Sieber -- 12/5/2002, 5:13 pm
Re: RE: Boom! - are you sure? *LINK*
Ross Sieber -- 12/5/2002, 4:23 pm
Re: Out there.
Don Flowers -- 12/5/2002, 3:15 pm
Re: Boom!
Shawn Baker -- 12/5/2002, 2:17 pm
Re: Out there.
Bruce -- 12/5/2002, 1:18 pm