Bias Cut Strips over outer stem

[ealger]

I plan to cover the outer stems, with a bias cut strip, after the initial glass wet out. I'm looking for ideas on how to treat the edges of the bias strip at the initial epoxy application. On my last canoe, the edge was lumpy and I messed around for days applying fill coats of epoxy on the bias strip edge in order to fair it into the rest of the glass. It took lots of scraping and sanding to get the bias strip edges to disappear.
Ed...

[Jim Dodd]

Hi Ed
How many bias strips are you going to but on?
I usually put on two or more.
Start with the widest one first. Usually I put the hull cloth on with the first wet out coat, and allow it to cure to the point that the cloth will not easily move.
Then trim excess cloth with a razor blade. Feather these edges with a curved knife, don't sand as the sanded area will show up later!
Now is when I put on the bias strips, and wet them out. When satisfied the strips are the way I want, I proceed with the rest of my fill coats on my hull and bias strips!
After I'm satisfied with the amount of fill coats and the hull is cured past the tacky stage, I feather the edges of the bias strips
I use System Three's "Clear Coat", others methods may vary with different epoxys.
Good luck!
Jim

[Glen Smith]

I scrape off the ridge left by the bias strips using a cabinet scraper and I do it before applying the fill coats.

[ealger]

I had planned to put on a single bias strip, fore and aft. I had such a difficult time last time I figured a single strip would suffice but 2 layers would be better. Perhaps an 8" strip followed by a 4" or 5" strip?

Jim and Glen, when you say scrape and feather the bias strip edge, are you suggesting to actually cut into the bias cloth feathering the edge? This I avoided before as I figured that the edge would then show after applying more epoxy?
Ed..

[Glen Smith]

I scrape and sand until the bias cloth is flush with the hull cloth at the seam and it doesn't show up through additional coats of epoxy. You are really cutting off the ends of the threads and that doesn't have the same impact as sanding into the hull cloth. Take it slow and stop as soon as the bias cloth is flush or still very slightly raised above the hull cloth.

The boat in this pic has one layer of bias cloth on the stems installed this way and it doesn't show at all, does it?

[ealger]

Thanks Glen, this make me feel a whole lot better about laying up the bias strips. I worked way to hard last time.
Ed...

[AlanWS]

Timing makes a big difference. You clearly want to wait until the epoxy has hardened, but if you trim within a day or two, it cuts easily with a knife, scraper, or surform. After a week of more (yes, it depends on the temperature and epoxy type) it gets hard enough to become quite difficult to trim, and sanding may be the best (slow!) option.

Another thing you can try is to put a plastic film over the wet epoxy and cloth, and press hard with a roller to feather out the edges. After it cures, you can peel off the film, leaving a much smaller smoothing job.

Here is a link to a website where the film approach was used on the entire hull of a stitch-and-glue boat. Incredible. http://www.pbase.com/dr_dichro/image/17276811

I've tried it for spot repairs, and it works well, though I've not tried it on stems. Make sure you use a strong enough film to peel off (heavy polyethylene, for instance) rather than something like saran wrap, which shreds when you try to remove it. It may be hard to use on a stem because of the compound curvature, and if you apply multiple layers at once, as I did on my stems.