Fiberglass on the bias

 Wood duck 14, fiberglassing the hull tonight (finally). Should I put on a strip of fiberglass cut on the bias along the hull seam? If so then how long should I extend the cloth and how far along the seam should I go? It only mentions a dart in the cloth to fold over the front in the manual but the videos mention bias cut fiberglass as do several other posts. Thoughts?

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RE: Fiberglass on the bias

Not done a WD (of any kind save for a decoy I designed & carved some 45 years back) but an observation on cutting fiberglass cloth on the bias:

In brief, it's tricky.

I wanted to apply strips of 4 oz. over the inside-hull fillets on my Waterlust. Being new to stitch'n'glue, and a bit less new to epoxy as an adhesive, I was a bit intimidated by the prospect of epoxy alone to sustain itself along these plank seams over time and use.

So I set about cutting some out of a width (wide is better if you want longer strips) of cloth with really sharp scissors. Found strands want to move, making any kind of accurate width strips really frustrating. So I switched to a wheel-knife and straightedge which worked great.

But any handling of the strips thus cut proved just how slippery fiberfglass weave is when there's no selvedge to keep things under control. You want to handle bias-cut strips as little as possible; I carefully rolled mine up once they'd been freed from the donor cloth, then carried them on small pieces of cardboard or ply to the hull.

Getting to the positioning stage, I chose to apply these strips to my fillets while the epoxy was still 'green' so it's sticky enough to hold the fibers in place while not so much that if you want to move something you can do so, but it's still obvious just how easily the fibers move out of alignment. This is also appropriate for bonding the weave-filling epoxy to the underlying fillet.

Filling the weave you want to do carefully, for the same reason. And trying to move strips at this stage is nearly impossible. Any lengthwise tugging will bring the edges in, narrowing your coverage. Once pulled narrower, the thinning is nearly impossible to correct.

I found those plastic "Bondo-blade" things to work best as they'd slide over the wetted cloth without catching filaments.

Lastly, keep in mind that everything you apply during construction adds weight. In some cases that weight can be beneficial, but if you don't subsequently remove any in the sanding stages, it all adds up.


RE: Fiberglass on the bias


I didn't bother with any bias-cut glass on my WD12 and it's still going strong after 13 years. I made the darts for the bow and used glass tape inside the deck-to-hull seam. On the outside I just ran the deck glass down 2 inches onto the hull. The bottom is just as described in the manual.

I do need to touch up the graphite/epoxy bottom every few years.



RE: Fiberglass on the bias

   Spclark, I have to laugh. Everything you describe I went through last night in a frustrating few hour experience that I wish to not repeat. After trying to utilize scraps I'd trimmed off the hull prior to glossing and having them basically disintegrate before my eyes I eventually gave up and went on without them. I found out that a ruler, cutting board, and pizza cutter are really no substitute for having the proper tools. Needless to say I had to clean up twice before making a mess with more glass and epoxy.

RE: Fiberglass on the bias

   Laszlo, after trying unsuccessfully to make some bias cut cloth I opted against it as well and ended up just double wrapping the bow and stern on the outside, tape on the inside. I contemplated using more tape on the hull seam but then went back and actually referenced your build notes and decided against it. Your build has been a lifesaver in a lot of these steps.

RE: Fiberglass on the bias

My apologies JoeK for the timing of my reply.

I read your post during my last break at work yesterday, about 3:15 but I was too focused on just getting to 5:00 & punching out to try and write my missive on my iPhone.

It was HOT here yesterday, hit 90°F yesterday afternoon & it's been high 80's most of this week so I was burnt... felt it better to wait until I'd had a shower, decent meal, good night's sleep before sitting down with my MacBook this afternoon after catching up with the garden watering & some errands. Otherwise I might have saved you the frustration.

On my W'lust I stuck with the manual's guidance for the exterior, doing much as Laszlo's described for the darts & overlaps. Hopefully the experience I described doing the bias strips on the inside will clear up any uncertainties for others who might later come across this thread.

I have three days off before going back to work, so my time's focused now on the last few things I need to do to get my Waterlust into launchable condition. It'll be only with the Mirage drive at the start; sailing kit's coming along OK but needs another month's work before that's ready.

Good luck with your WD14, take us along when you take it out for the first time!

RE: Fiberglass on the bias

   No worries Spclark, the frustrations are half the journey. Life is never cut and dry. The weather has been hot/humid here too, so I know we'll the frustrations you speak of. My shop is in the basement with the dehumidifier, so the temperatures are a bit cooler and drier there than the rest of the house. On a regular day I'm in a hurry to run down there after a long day working outside. You enjoy your time off from work, any time away is good time away. I'm sure I'll have more questions, and between these threads and the Facebook community board there haven't been any questions that have gone unanswered.

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