Submitted by windsurfer18 - Sat, 12/11/21 » 6:26 PM
I recall from a strip plan canoe I built years ago that we used bias cut cloth to wrap the stem and stern. I noticed that CLC isn't specifying that for the Shearwater
Prolly 'cause bias-cut strips (cut from cloth so warp and weft threads are at 45°) are pretty hard to manage if you haven't done much with fiberglass before.
Without the woven selvedge of tape those threads want to go their separate ways if you even look at 'em cross-eyed, let alone try to get 'em to march in lockstep once you start bedding them in epoxy.
Where the additional strength of all the threads crossing a joint is worth the effort it's a useful skill learning to wrangle 'em into place compared to taking the alternate route of strips cut from cloth so that you end up with a bunch of equal length threads (cross-wise to the joint) held together by really long threads that, at the edges, tend to want to take a different line.
One advantage of this technique is that you can pull some of those long threads out at the edges before (or after) bedding in epoxy so there's less 'glass to sand fair once the epoxy's clicked hard enough for sanding. Makes for a good technique when 'glass is called for over fillets if plans call for adding more 'glass later on; leaves less of an edge to telegraph it's presence under subsequent layers of cloth.
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RE: No bias cut cloth on stems?
» Submitted by spclark - Sat, 12/11/21 » 8:04 PM
Prolly 'cause bias-cut strips (cut from cloth so warp and weft threads are at 45°) are pretty hard to manage if you haven't done much with fiberglass before.
Without the woven selvedge of tape those threads want to go their separate ways if you even look at 'em cross-eyed, let alone try to get 'em to march in lockstep once you start bedding them in epoxy.
Where the additional strength of all the threads crossing a joint is worth the effort it's a useful skill learning to wrangle 'em into place compared to taking the alternate route of strips cut from cloth so that you end up with a bunch of equal length threads (cross-wise to the joint) held together by really long threads that, at the edges, tend to want to take a different line.
One advantage of this technique is that you can pull some of those long threads out at the edges before (or after) bedding in epoxy so there's less 'glass to sand fair once the epoxy's clicked hard enough for sanding. Makes for a good technique when 'glass is called for over fillets if plans call for adding more 'glass later on; leaves less of an edge to telegraph it's presence under subsequent layers of cloth.