Alternative materials, initial wet out weights

Fiberglassing over plywood and one-off fiberglass methods. See: "Boatbuilding Methods", in the left-hand column of the Home page.

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Alternative materials, initial wet out weights

Post by Oyster »

I thought I would pass this along for anyone interested in some of the alternative fabrics, as was being discussed in another thread. These numbers were provided by a good friend as a reference point when weight is a consideration. Of course in that mix while most framed boats are skinned with finish cloth, there are times where people do consider a more abrasive surface from what the finish cloth gives you.

And in some of the tape and glue builds there are occasions to use the biaxal cloth. But for anyone doing some research when considering the uses of the other fabrics, as stated keep in mind that your filler resin and fairing using resin and your agent will add additional weights to the numbers. Weight is always a critical point when building the smaller boats and can create some performance and even safety issues if you get too crazy with the add ons from the raw wood materials. But you can translate these numbers when you are ordering your resins, as long as you know the weights of your particular brands of resin. There is a wide variety of viscosities , including the resins stated for gluing and not just wet out.

As usual, YMMV with your own particular results.

For those interested in the weight of these sheaths I offer these numbers from my testing. They do not include any fairing materials and that would add more to the Xynole weight than to the glass because of greater roughness of the saturated Xynole and Knitex that needs to be covered up.

Sheathing weights:

One coat of epoxy = 0.036 lb/sq ft
Two coats of epoxy = 0.059 lb/sq ft
Three coats of epoxy = 0.081 lb/sq ft

6 oz FG cloth w/3 coats epoxy = 0.142 lb/sq ft

10 oz FG cloth w/3 coats epoxy = 0.195 lb/sq ft

XYNOLE cloth w/3 coats epoxy = 0.36 lb/sq ft

KNITEX biaxial (non woven) FG cloth w/3 coats epoxy = 0.46 lb/sq ft 1808

These sheathing weights are approximate and will depend on how the individual applies the materials but may be helpful for those interested in these details.

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Re: Alternative materials, initial wet out weights

Post by JoeM »

Good information to have. Thanks!
Check out my project and blog!

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Re: Alternative materials, initial wet out weights

Post by kens »

If I read that correct, 6oz cloth + 3 coats comes out to 7sq ft = 1lb
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

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