: I build
: 'DITTO'
: kayak heresy
: brett the hitman hart
Brett: I haven't worked with this stuff but recall having my interest peeked by a brochure that came with my builders supply bill. I looked around the store for it but couldn't find it. My office is in a converted 19th century felt factory. They're building an addition here and I think the masons are using a similar material to cover beadboard foam with stucco. They're using large sheets to cover all the foam before applying the scratch coat.

My advice is to get some of the stuff and build some samples for destructive testing. In my experience the wood making up the plys fails first. That is, the wood fibers tear apart before the ply gluelines, the epoxy or the drywall tape fail.

As most S&G designs rely on the taped joint to fasten the thing together, any weakness in the structure will show up here as most of the stresses are going to be concentrated at the joint. If the surface of the plywood is the weakest point in the composite structure and all these joints rely on this surface as a major part of the joint, your goal should be to tie in as much wood surface as possible as part of the joint. I doubt that a 3 or 4" FG tape ties enough wood surface into the joint to balance the strength of the tape. Additionally, the FG tape produces a hard edge where the flexing and tearing stresses are concentrated. This is going to promote wood fiber failure.

Sam Devlin, who designs much larger and heavier multichine ply boats advises using 3 to 4 layers of tape of increasing widths to prevent such a hard edge. Clearly, such a build up of FG tape in a yak is overkill. But layers of these lighter meshes can serve the same purpose, as well as, tying more surface into your joint. So far from being kayak heresy, I think exploring the use of these materials is just sound thinking. After all how many builders out there are streaching walrus skins over drift wood frames?