Boat Building Forum

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Dynel vs. Glass fabric
By:Paul G. Jacobson
Date: 10/31/2007, 12:53 am
In Response To: Re: Good Suggestion, PGJ!! (William Cruz)

: Paul, how long have you been building?...was this one of your first
: boats?...Thirteen years old...this canoe, good long time to be building.
: Figure ten thousand hours of practice to gain expertise in
: "anything"...and judging by your suggestions on the
: KBB....you've got some good stuff to share!

Working with wood goes back three generations on my father's side. For all I know I may have a Scandinavian ancestor who made longboats for viking voyages. I wonder what my grandfather would think of a biscuit joiner.
Somehow life got in the way of those 10,000 hours of potential boatbuilding time. But 1000 hours of making mistakes, and working out solutions to them can slowly teach you some things.
. . .

: What's Dynel?

This is the description of Dynel from www.Defender.com Defender's catalog has a few pages describing the working properties of several reinforcing fabrics they sell. The paper catalog is easiest to use, but you can (eventually) find all you want on their website.
- - - - - - - - -
Dynel is an exceptionally popular laminate fabric most importantly for its ability to be handled without generating irritant or allergenic reactions from skin contact.
Strong and versatile, Dynel is supple and soft like a true woven fabric with no fibers to irritate your skin and is made of yarn which is exceptionally pliable to easily conform to complex contours, curves and corners.
The weave of Dynel is not tight to ensure ease of use, fast wet-out and modest texture making it ideal for decking or cabin topping.
For these reasons and more (below) Defender's Dynel is used for museum-quality restoration work on wooden boats world-wide as well as for many applications outside the marine field by persons of all different levels of skill and skin sensitivity working with laminate cloths.
Excellent adhesion: for laminates, adhesion is essential, and Dynel is excellent: in fact, it is nearly perfect. It wets out readily and adheres well to polyester and epoxy resin. There are no voids or capillary spaces leading from the surface of laminate to serve as initial starting point for further degradation. The wet out is instantaneous when resin is applied.
Increased durability: adding a layer of Dynel to the surface of a laminate as hull reinforcement provides increased resistance to abrasion, and improves the laminate's ability to respond favorably on impact and to resist deterioration.
Fracture resistance: as an overlay over glass, it preserves the surface against miniscule fractures that often occur in fiberglass gel coat.
Reduced surface friction: higher performance is attained by boats using Dynel as an overlay, because the slick Dynel surface has less friction. Crazing is reduced substantially.
Low weight/high strength ratio: Dynel is relatively light-weight (4. 2 Oz. Per square yard, 17 x 17 weave. ) In ratio to its tensile strength. Dynel can absorb work loads 6-8 times greater than glass. Dynel will have more limited physical properties when used alone rather than as an overlay. Ideally suited for planking on larger boats that work in rough seas, provided more than a single layer is used; decks will require several layers.
Easy application:
1) smooth fabric over one side of the hull or other surface after all fittings have been removed.
2) staple fabric in place or use other means to hold it while you use a scissors to cut off excess along edges and at ends.
3) coat the fabric with epoxy or polyester resin, depending on which is appropriate for your application.
An alternative application would be to saturate the cloth with resin on a worksheet and then to lay the Dynel saturated with resin in place, provided the cloth was cut to size in advance.
Note: Dynel can be used in conjunction with other laminate fabrics such as fiberglass, xynole or if the condition of the boat demands laminate layers with different performance characteristics. Width - 63".
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The actual page for the above quote is: http://www.defender.com/product.jsp?path=-1|10918|16458|309346&id=16067

: Did you use screws to put those gunwales on? I epoxied mine...thinking to
: cut down on weight...and hoping I wouldn't have to replace them.

I started with brass screws and had almost all of them break off while I tried to install them. Even with pilot holes the brass isn't strong enough to work in the oak. I ended up using ordinary zinc plated steel screws. Over time they rusted. The fun part is pulling them out.

: . . . I've got a couple of very good scratches that went through to the wood
: on our canoe...basic layer of cloth and fill on her, so maybe those two
: layers of six ounce cloth did what you intended them to do...

I'm hoping that the single layer of Dynel will do just as well. Or at least be adequate for my needs.

PGJ

Messages In This Thread

Epoxy: Anyone know about these brands???
Gennie -- 10/28/2007, 9:20 am
Re: Epoxy: Anyone know about these brands???
Don Lucas -- 10/31/2007, 10:06 am
Re: Epoxy: Anyone know about these brands???
William Cruz -- 10/30/2007, 10:12 am
Re: Epoxy: Anyone know about these brands???
Carl H -- 10/29/2007, 5:55 pm
Re: Epoxy: Anyone know about these brands???
Pat Deopp -- 10/29/2007, 12:42 pm
Re: Epoxy: Anyone know about these brands???
Gennie -- 10/29/2007, 4:35 pm
Guinea pig?
Paul G. Jacobson -- 10/30/2007, 12:12 pm
Good Suggestion, PGJ!!
William Cruz -- 10/30/2007, 2:15 pm
Re: Good Suggestion, PGJ!!
Paul G. Jacobson -- 10/30/2007, 6:10 pm
Re: Good Suggestion, PGJ!!
William Cruz -- 10/30/2007, 11:37 pm
Dynel vs. Glass fabric
Paul G. Jacobson -- 10/31/2007, 12:53 am
Re: Dynel vs. Glass fabric
Rob Macks / Laughing Loon -- 10/31/2007, 8:30 am
Re: Dynel vs. Glass fabric
Paul G. Jacobson -- 10/31/2007, 7:55 pm
Dynel is tough for paddle edges. *Pic*
Reg Lake -- 10/31/2007, 11:09 am
Re: Good Suggestion, PGJ!!
Mike Savage -- 10/30/2007, 5:41 pm
Re: Good Suggestion, PGJ!!
William Cruz -- 10/30/2007, 11:23 pm
Re: Good Suggestion, PGJ!!
Mike Savage -- 10/31/2007, 6:53 am
Re: Epoxy: Anyone know about these brands???
Paul G. Jacobson -- 10/28/2007, 1:13 pm
Re: Epoxy: Anyone know about these brands???
Paul G. Jacobson -- 10/28/2007, 12:30 pm