fiberglassing the stems

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WMegl
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fiberglassing the stems

Post by WMegl »

I have a question regarding how the fiberglass cloth is cut at the outer stems. Ted calls for cutting the cloth after saturation with resin within 1 in. (beyond) the outer stem. Then, 3 hours later after the epoxy has firmed up, the cloth is to be cut cleanly at the stem. Is this at the outer edge of the stem so that the side of the stem is covered with the cloth? This would leave the forward edge of the stem, where the stem band is to be installed, the only part of the outer stem not covered with fiberglass cloth.

Ted also states the cut edge of the cloth should be tidied up with 120-grit sandpaper. If the description above is correct, then I am sanding the edge of the cloth as well as the surface (or nearly so) where the stem band is installed- correct?

Thanks.
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Patricks Dad
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Re: fiberglassing the stems

Post by Patricks Dad »

I think you understand Ted's directions correctly. One addition to consider:

Cut a strip or two of glass on the bias (45 degrees to the direction of the weave) long enough to extend the length of the stem. Lay that glass over the outer stem overlapping the hull glass. Glass cut on the bias will wrap nicely around the outer stem providing a layer of additional protection for the stem and capture the bare edge of the underlying glass. The stem band can lay over top of that extra layer of glass. If you do more than one layer (you may decide not to give you have a stem band - some people put multiple layers here and dispense with the stem band altogether), make them different widths so you can feather the structure out to the rest of the hull.
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WMegl
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Re: fiberglassing the stems

Post by WMegl »

Very good idea. I will probably add the layer for extra protection because I do a lot of canoeing and add the stem band as extra protection and I like the look. Thanks.
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WMegl
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Re: fiberglassing the stems

Post by WMegl »

Randy: At what point would you apply the extra strip of bias cut cloth over the end of the stem and first layer of fiberglass cloth and resin? When the first layer is still wet, or after it is ready for the second coat or resin, or after it has cured?

Thanks.
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Patricks Dad
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Re: fiberglassing the stems

Post by Patricks Dad »

I put my 2nd layer of glass on the stems along with the 2nd coat of epoxy (which I put on soon after the first coat is no longer tacky).
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WMegl
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Re: fiberglassing the stems

Post by WMegl »

Sounds good. Thanks.
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WMegl
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Re: fiberglassing the stems

Post by WMegl »

Randy: Since the rectangular piece of fiberglass will be covering a curved object, should I cut "V's" in the side of the fabric that will extend over the strips to as to prevent the natural overlaps?

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Patricks Dad
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Re: fiberglassing the stems

Post by Patricks Dad »

No! Cut the rectangular piece of glass at a 45 degree angle to the weave and it will wrap nicely around the stem. This is called "cutting on the bias" I believe.
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KenC
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Re: fiberglassing the stems

Post by KenC »

I deviated from Ted's method.

I cut the cloth about 3" beyond the stem on both sides. Then as I was wetting out the cloth, I first wrapped one side around the stem, and then the other. When that had partially cured to tacky, I then added a bias-cut strip along the stem, so that in the end there were three layers of 6 oz glass protecting the rounded over stem. It has stood up well to a fair amount of abuse. My kayak is due for a refinishing and a few gouge repairs in the bottom, but the stems are doing just fine.
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WMegl
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Re: fiberglassing the stems

Post by WMegl »

All: I added a bias cut strip of cloth to the outer stem during the application of the second coat of resin. It turned out well, except I did not successfully featheredge the cloth to the surrounding epoxy surface. I now have a discrete cloth edge in the surface.
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I would appreciate your comments on my plan to fix these areas. I will sand the cloth edge until smooth or as smooth as I can get it to the surrounding area. I will certainly be sanding into the cloth. I will then apply several coats of epoxy resin until smooth. Ted mentions in the book that it's difficult to featheredge succeeding coats of epoxy, so I will try to get it on as thin as possible. Since the entire hull will be sanded prior to varnishing, I will try to get the new epoxy featheredged into the surrounding areas at that time.

I have included some pictures of the hull for anyone's interest.

Thanks.
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KenC
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Re: fiberglassing the stems

Post by KenC »

I'd use a cabinet scraper rather than sandpaper, and start as soon as possible, before the epoxy reaches full cure, if possible. Hull looks amazing.
sedges
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a different approach

Post by sedges »

My approach to using fiberglass to reinforce stems has been different. I don't use a hardwood outer stem, so this is over the shaped ends of the strips. I use bias cut glass strips and apply them before the hull cloth goes on. I let them cure enough to sand the edge as smooth as I can get without gouging the soft cedar. One thing that I have learned over the years is to cover the wet out glass with saran wrap and squeege over that to flatten the edges and feather them out. Works really well. Sometimes I have to do very little sanding before glassing the hull. I bring the hull glass all the way over the stem glass.

Depending on how the canoe will be used I use heavier or lighter cloth for the stem or multiple layers with the edges staggered.
KenC
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Re: fiberglassing the stems

Post by KenC »

I also used the saran wrap method while glassing the stems. Didn't have too much feathering of errant strands to contend with, but all of the wrinkles in the saran translated into a "wrinkled" surface on the underlying epoxy, which probably, in the end, took just as long to deal with. I'm sure it will work better next time (doesn't it always?)
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Grumple
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Re: fiberglassing the stems

Post by Grumple »

Sorry if this has already been answered, WMegl, but what kinds of wood are you using for your strips?

I really like the way your hull looks!
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WMegl
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Re: fiberglassing the stems

Post by WMegl »

Grumple: I used 4 boards of western red cedar. The long accent strips the length of the boat are ash and walnut. On the bottom, the accent strips are redwood (stained with Minwax waterbased stain) and maple.
The side accents midships are redwood(stained), cherry(stained), and maple.

I laid the strips, which I categorized according to color/grain, identical on both sides of the hull: dark, grainy, light for the most part. Two strips on opposite sides in the same position were adjoining strips ripped from the boards although I doubt this faux butterflying (they aren't actually butterflied, just cut at the same time) will be noticeable.
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