What is an appropriate radius for the bow and stern stems?

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David James
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Location: Glenview, Illinois

What is an appropriate radius for the bow and stern stems?

Post by David James »

I'm wondering what radius to sand my Rob Roy stems down to. For my first boat I installed 3/8" brass stem bands, but this time around, in the interest of keeping weight down, I plan to just add reinforcing layers of bias cut 'glass.
Should I still go with a 3/8" radius? What looks good, is not too blunt, but not too vulnerable either? They're maple, and the canoe will see light duty.

Thanks, Dave :thinking
"If given six hours to chop down a tree, spend the first four sharpening your ax." - Abraham Lincoln
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Glen Smith
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Post by Glen Smith »

I always go for 3/8". Fiberglass strips cut on the bias will follow this radius very well.
David James
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Joined: Tue May 11, 2004 9:04 pm
Location: Glenview, Illinois

Post by David James »

Then I'll go with 3/8" Glen, thanks. I'll be rounding them over this morning.

When should I apply my bias cut strips? Do they go on after the fill coats, or right after the wet out? Also, is it best to brush on the epoxy on and then lay the strip on to the wet epoxy?

thanks again, Dave
"If given six hours to chop down a tree, spend the first four sharpening your ax." - Abraham Lincoln
pumpkin
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Post by pumpkin »

I applied the stem strips right after the wet out as soon as the hull epoxy set up but while still "green". I found that putting the bias strips on cardboard and wetting them with a roller easiest. Then I applied them to the stems and smoothed them out, one right after the other. Fill coats followed and it is seamless looking.

I'm interested to hear how others do it.

Matthew
David James
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Location: Glenview, Illinois

Post by David James »

Matthew, since I don't plan on using brass stem bands, how many bias strips should I put on? Should I do 2 or 3, or just one? I have 6 oz. cloth that I'll use for them, the rest of the hull covered with 4 oz.

thanks, Dave
"If given six hours to chop down a tree, spend the first four sharpening your ax." - Abraham Lincoln
pumpkin
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Location: North Dakota

Post by pumpkin »

I put 2 layers on the outside and inside using 6 oz cloth. I used full double layers of 6 oz cloth on everything actually. For the stems I cut the first layer about 4 inches wider and longer than the second. I also used a cabinet scraper before applying the bias strips and also before putting on the fill coats to knock down any high spots and fluff to make a nice feathered edge. I found that the feathered edge took a bit of scraping between fill coats and a couple of extra, light fill coats to get a really nice final surface. A sharp cabinet scraper really smoothes it out nice.

For all of my epoxy application I used 6" hotdog rollers from Sherwin Williams and aluminum fiberglass rollers from US Composites. The 4 inch aluminum is a sweet roller, it presses down the cloth nice especially in the inside of the stems. I should have put more effort on the inside stem area but I put in stem float chambers with Beckson Deck plates to use as dry storage so I got lazy.

I built an 18 foot redwood Micmac and the final weight is only 67 pounds even with 4 total layers of cloth. I am very happy with that. We have use it a lot an haven't caused any damage to the stems yet. The whole thing is solid. Good luck!!!

Sorry for the late reply, we went for a paddle. :smile

Matthew
David James
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Location: Glenview, Illinois

Post by David James »

Matthew, last night I did my wet out and that went really well. This morning I was in the garage at 4:30 am and applied the first fill coat. It's really lookin' good now. After lunch sometime I'll get out there for another fill coat.
I took a look at the 6 oz. 'glass leftovers from my first camoe and none of them are long enough to cover the stem. (I know, good time to check, right?) Do you see any reason why I couldn't just apply two or even three pieces instead of one? This is done for impact resistance right? So, as long as I'm able to feather in the edges...? What do you think?
Or I could use some of the 4 oz., of which I have plenty. Heck, maybe the 4 oz stuff would be easier to feather... :thinking

Dave
"If given six hours to chop down a tree, spend the first four sharpening your ax." - Abraham Lincoln
pumpkin
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Joined: Fri Jan 22, 2010 9:18 pm
Location: North Dakota

Post by pumpkin »

Dave, I'm a realist not a perfectionist. If I had small pieces of 6 oz long enough to do the stem to about half way up, then I would use one layer of 6 oz and probably a couple of layers of 4 oz for full stem coverage. Really, the abrasion resistance is only necessary below the waterline. If you are like me, seeing what is above the water is easy. I usually scrape that stupid rock that us just below the water or on the beach. The difference in feathering should be minimal. It will work, don’t worry. Once you are done, drive it like you stole it.

You should post some pictures.

Matthew
David James
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Location: Glenview, Illinois

Post by David James »

Matthew, thanks for your quick and no nonsense reply. I'll go with a single piece of the 6 about half way, then all the way with the 4 oz.

Hey, I've got time, I could snap a few shots and post 'em if you want.

Dave
"If given six hours to chop down a tree, spend the first four sharpening your ax." - Abraham Lincoln
David James
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Location: Glenview, Illinois

Post by David James »

Matthew, here are some shots of the Rob Roy.

Image

Image

Image
"If given six hours to chop down a tree, spend the first four sharpening your ax." - Abraham Lincoln
pumpkin
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Post by pumpkin »

Very pretty. You should be very proud! I like the feature strip and the football, the maple contrast is beautiful. In short order you should be able to get it wet. (and scratched)

It makes me want to start another. I’ll have to get things in order and start looking at designs.

You made me smile Dave. :applause

Matthew
David James
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Joined: Tue May 11, 2004 9:04 pm
Location: Glenview, Illinois

Post by David James »

Thanks Matthew. I'm not too happy about the feature in the football area. The idea was, the light colored football outline represents the gunnels, and the light rectangular area the seat... Sort of like the canoe itself, which will have a similar seat installed. Kinda goofy, but I wanted something different.
It's now 3:00 here, and my first fill coat is almost hard enough for the next coat. My plan is to tape some thick garbage bag plastic to my bench top, and then wet out the reinforcing strips on that nice slick surface. The strips should peel off I guess.
I'm gonna head out now to prepare for the second (last?) fill coat.


Thanks again for the kind words, Dave
"If given six hours to chop down a tree, spend the first four sharpening your ax." - Abraham Lincoln
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Glen Smith
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Post by Glen Smith »

With wet-out bias cut strips you have to be very careful or it will stretch out of shape. I brush a coat of epoxy on the stem then drape the dry, bias cut strip over the wet epoxy and lightly work on it with a brush until the strip is completely wet out. Then I delicately squeegee off the excess with a small squeegee or piece of credit card.
David James
Posts: 223
Joined: Tue May 11, 2004 9:04 pm
Location: Glenview, Illinois

Post by David James »

Glen

I just cut the strips and found them to be very flimsy to handle, so what you say makes sense. I'll try it your way.
I guess the worst that can happen is the strip gets all messed up and I have to remove it and try again.
I like your credit card idea. Visa or Mastercard? :razz

Thanks, Dave
"If given six hours to chop down a tree, spend the first four sharpening your ax." - Abraham Lincoln
David James
Posts: 223
Joined: Tue May 11, 2004 9:04 pm
Location: Glenview, Illinois

Post by David James »

Glen, and Matthew,

I just finished my second fill coat and layed on a 6 oz. strip and then followed up with the overall 4 oz. strip. Glen, applying the strips as you suggested worked like a charm. Squeegeeing was very touchy but I think I'm all right. (There are some fuzzy edges that I hope will disappear when I sand.)
It's pretty cool the way the bias cut enables the fiberglass to conform to the stem so well. Nice. I might even add another strip.

Thanks for the help guys. Dave
"If given six hours to chop down a tree, spend the first four sharpening your ax." - Abraham Lincoln
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