Greg Root recently asked about doing a lightweight-cloth layup and I've been meaning to post what I think the method could/should be and see what tips/criticisms it gets. I'd give the main generator of these ideas credit, but he no longer has a website to link to and so I can't give him the credit.

Assumptions: The layup in question involves multiple layers of 3.2-oz. satin-weave cloth and epoxy. Given that this is tight-woven cloth, resin has a more difficult time penetrating the cloth, so the assumption is that epoxy should be laid on first, then the cloth rolled on, to work the epoxy in from the underside and reduce the amount of trapped air. Also, the method assumes that subsequent layers should be applied as soon as possible so that the subsequent epoxy bonds most strongly with the previous layer, and to speed up the lay-up process.

1) Seal Coat: Apply a skim of epoxy very lightly, as I really don't think much penetration is necessary -- just enough to seal it and provide grip for subsequent layers.

2) First Layer: Applied when the seal coat becomes stiffly tacky -- the point where it isn't too gooey, but that it is still 'dentable', or leaves fingerprings. (I know, you ain't supposed to touch it with your bare hands...:) Roll part of the fresh epoxy over the tacky epoxy. How much exactly I'm not yet sure -- probably about half or more of what's necessary to fill the weave, but not so much that it runs before you lay the cloth on. Have your cloth pre-rolled onto a section of pool noodle, as was recently suggested, or PVC pipe. Roll it down the keel or center of deck -- a friend may prove very helpful -- carefully squeegeeing and smoothing the cloth down as you go. Then go back for a more forceful sqeegeeing to force the cloth down as tight as it will go to the hard surface. Roll on the rest of the epoxy.

3) Subsequent Layers: As 2)

4a) Fill: If you plan on all your layers being structural, then apply 1 or 2 rolled-on and squeegee'd fill coats to fill the weave.

4b) Sacrificial Layer (optional): On the hull exterior, to be done instead of 4a) Lay on one more layer of cloth and do not fill the weave. Instead, when you sand the boat prior to varnishing, just sand the cloth smooth. It will lose its structural strength, but will add abrasion resistance. Supposedly this method also makes that sanding job quicker, because less material needs to be removed -- it isn't as lumpy as a layer of 6-oz. that's been filled with 3 layers of epoxy. Downside: costlier than a thin fill coat.

5+) Sanding/varnishing/etc.

For Greg:
The layup recommended by the unnamed individual (kind of taboo, like talking about the dead) was posted on 7/26/99. Layup is given as inside glass/core/outside glass.

http://www.guillemot-kayaks.com/KBbbsOld/15516.shtml

deck: 2@3.2oz satin glass / .125" cedar or redwood / 1@3,2oz satin glass

add a third layer of 3.2oz satin glass to the deck where your knees push when you brace

hull: 5.0 or 4.8oz satin kevlar / .125" cedar, redwood, or Okoumee plywood strips / 4@3.2oz satin glass

3@3.2oz satin glass can be used instead of the kevlar. If you use kevlar lay it up very dry it will get wetter as time passes.

Dean