Alan's Bloodvein II Canoe Strip Build

[Gamma1214]

You cut these off the boat, epoxy them together and then fit them as one piece? I could do that but then fitting both ends to have nice, tight joints at the ends would become much more difficult.

I usually have to make the last cut (where I'm running the pull saw between both sides) 2-3 times to get it tight and, of course, every pass shortens them just a little. That's why I do the mid-ship scarf last. The shape of the hull makes getting an accurate measurement difficult (every time I tried to measure on the first one, I cut it short), so I've gone to cutting them in place.

I think I know how to make a jig that will allow me to cut a consistent, shallow angle on the hull and can be used on any hull shape. I should be able to get one made this afternoon & we'll know if it works in real life like it does in my head.

 

[Alan Gage]

You cut these off the boat, epoxy them together and then fit them as one piece? I could do that but then fitting both ends to have nice, tight joints at the ends would become much more difficult.

I just don't worry about tight joints at the ends. If there are float tanks I make them flush with the gunwales so the inwales die into them. If there are no float tanks then I "intentionally" leave a gap where the inwales meet and claim it's for water drainage. The outwales are trimmed flush with the stem and then the tips are rounded off until I think they look right.

Alan

 

[Boatman53]

If it is up to me I intentionally leave a gap to let water drain out.

Jim

 

[Glenn MacGrady]

Admin interruption:

This is a very popular and informative thread about strip building a canoe, and is still ongoing, but the title ("Alan's Bloodvein II") is very ambiguous for search engine word "grab-ability". So, I added the words "canoe" and "strip build" to the title to improve the SEO for future searchers and researchers.

 

[Gamma1214]

If it is up to me I intentionally leave a gap to let water drain out.

Interesting. I wonder how that would look if I left the inwale short & wrapped the outwale as I've been... might try it that way when finishing the "Extra Trippy Merlin... (wood strip... canoe build)"

Just kidding, Glenn. Edit as you wish... whatever grabs your search engine.

 

[memaquay]

My ends are seldom perfect, and like Alan I see it as a drainage hole, lol. I have a process for installing inwales, it doesn't involve math, measuring tapes or common sense. My inwales are intentionally long, I clamp them as far as I can, starting from the center, with the ends riding high over the stems. Then I eyeball the inwale where it crosses the end of the stem, draw a line and cut it to fit. 6 times out of 10 it doesn't look very good, but it's fast and dirty, just the way I like things. I'm actually going to be doing this tomorrow if everything works out, I'll include a picture for the "fine art of wood butchery" scrapbook.

 

[Alan Gage]

My ends are seldom perfect, and like Alan I see it as a drainage hole, lol. I have a process for installing inwales, it doesn't involve math, measuring tapes or common sense. My inwales are intentionally long, I clamp them as far as I can, starting from the center, with the ends riding high over the stems. Then I eyeball the inwale where it crosses the end of the stem, draw a line and cut it to fit. 6 times out of 10 it doesn't look very good, but it's fast and dirty, just the way I like things. I'm actually going to be doing this tomorrow if everything works out, I'll include a picture for the "fine art of wood butchery" scrapbook.

That's exactly how I do it as well.

On the last couple I haven't even drawn a line. I just eyeball it with the pull saw as my sight line and then cut when it looks close.

I've tried other methods that involve more measuring, clamping, marking, and fancier cutting but they all end up with the same homely looking ends.

Alan

 

[Gamma1214]

You guys are awesome. There are SO many times that I think I should aspire to be more craftsman-like... thanks for keeping me grounded.

I spent 3 or 4 hours in my friend's gun shop tonight and went through a couple of variations before landing on what I think is going to work great. Dave's an awesome machinist and I'm often surprised that his love of precision and my embodiment of "meh, that'll (probably) work" don't have us choking the crap outta one another.



He also loves to talk and is usually incapable of working & talking at the same time. By the time we were done, I was itching to give it a test run but I knew that would lead to mixing epoxy, installing the gunwales and spending 1/2 the night in the shop... There's always tomorrow, right?

 

[Boatman53]

Sign of a true craftsman. “He also loves to talk and is usually incapable of working & talking at the same time.”
Can’t wait to see what he/you came up with.
Jim

 

[Gamma1214]

Sign of a true craftsman.

Definitely describes him. I often tell him that he "tasks" better than just about anybody I've ever met but doesn't "multi- task" worth crap.

I got to test drive the jig today and I'm pretty pleased. Drawing inspiration from a small combination square (you might notice my short scarf at the top of the square... I was really close to 45°)


The jig started out as a 2" x 5" piece of 3/4 inch thick aluminum. We (again, somewhat arbitrarily) chose 12 1/2 degrees as a suitable angle and Dave machined a small lip onto the block



With aluminum flying everywhere (notice the cardboard containment shield in yesterday's photo), he then cut the 12 1/2° angle and added a slight undercut to allow for the kerf on the pull saw blade



The hope was that the remaining width (above the kerf cut-out) would be sufficient to guide the saw and it actually works well.

First step was to clamp the gunwale securely and I used a large c-clamp and added a piece of Cherry gunwale scrap to the outside in order to account for the overhang



The large c-clamp allowed the pull saw to pass through it and I held the saw against the jig as I (using light pressure to help prevent distortion) eye-balled my end point and sawed off the shallow scarf



By the time the saw was making contact with the sheer, the blade was deep enough that the gunwale could act as the guide and I removed both clamp and jig and finished sawing through without hull contact.



I repeated the process to remove the other shallow scarf and then grabbed one of the discard pieces from the other day.

This was clamped differently as I decided to cut it off of the boat.

I added a piece of Cherry gunwale scrap to square it up, placed the jig on top and clamped the whole mess to one of the boards of the off-loading table



This was, in my opinion, the test for the jig; to see if the angles were consistent and repeatable. I am very pleased to say that it works well even if it's a little wonky getting used to holding the saw against it.



I then marked the other end of the repair piece and thought I cut it a little long but, it seems that I'll need more practice.



I used that too-short piece as a guide for another and then cut it too short also.

By this time, I was running out of inwale stock so I shortened one of the too-short pieces a bit further and used the other as donor material until I got it close enough. It puts 2 scarfs very close together but it's (I think) probably as strong as the original 45(ish) angle would have been so I'll live with it.



Being hungry, I decided against mixing the epoxy and headed home feeling reasonably good about myself... That lasted until a few hours after supper.

I'd taken the seat frame home to finish sealing it so I marked the locations of the paracord & started weaving. I've always worried about the paracord stretching & becoming loose so I try to remove all of the stretch by pulling it as tightly as I can every time I cross the seat.

It seems that, at least today, I was stronger than my Sassafras / Oak lamination and I wound up breaking the seat.



Now I'll need to soak, bend & dry, epoxy, mill, assemble and weave another seat asap. I guess I know what I'm doing tomorrow after horses.

 

[sailsman63]

That takes me back... I ran into something similar when I was working on the seats for my tandem (I also use tightly strung paracord). I think there are photos around...

The upshot is that the greatest load on this kind of frame is inward along the lacing, especially when you're sitting on it. Those curved front and rear frame pieces then translate that force into a significant amount of torque. While it looks like you're trying to stay light, I suspect that you'll get better results if the joint geometry provides full support to the inner edge of those front and rear rails.

 

[Gamma1214]

True and that's been mentioned before in my other builds. I'm not crazy about the time crunch but I typically don't mind taking things all the way to failure because you can learn alot.

In this case, I think I needed more clearance in the dado joints since the sides of my cross rails show little sign of damage which, to me, would indicate very little (if any) epoxy was holding those surfaces. Only one of those 4 joints held well enough to tear out the surrounding wood and I'd think that the epoxy should be much stronger than the wood.



My conclusion is that either I had insufficient clearance to allow epoxy penetration or the wood was impervious to epoxy. (I'm going with door #1 and, regardless of which direction I run the dado in the future, it will have a loose fit.

As you said, the way it failed also indicates some serious downward / inward pressure as both sides failed on the front rail. I'm not too terribly worried about my Raven seat at this point (made exactly the same way) because it's now bolted to tabs that are epoxied to the hull. I think that will provide adequate support to the underside and prevent the twisting forces required to break the joints but I could be wrong.

Note: Anyone taking it for a spin at WPASCR might want to paddle it early and wear fast-drying clothes.

Options at this point are: 1) weave the seat after installation so that the hull provides extra support. No way that's happening

2) Increase clearances slightly and trust that better epoxy penetration provides enough strength to hold it.

I'd be more comfortable with that if not for the areas where the wood itself failed. To me, that indicates a need for more material in general and I may still be too close to the edge for comfort.

3) Completely revise my dado to provide enough support to prevent the twist even before the seat is installed. On any trail, ounces are pounds and pounds are pain but I think this is one place I can suck it up. (I carry a perk coffee pot for goodness sake because I can't stand instant... I can tough it out so I don't have to kneel for weeks when the seat breaks)

I'm pretty sure that I thought of a way to repair this frame without rebending fresh wood (which I don't currently have unless I change species). Might not be pretty, but if it works, it will make the WPASCR deadline much more feasible.

 

[Cruiser]

We did cover this a build or so ago, that lap joint over the top IMO, is part of the problem ...I would suggest making a simple dado on the side of the front and rear rails. I usually run a screw in to act as a clamp, then replace with a dowel (helps with that torque from that bend) after the epoxy sets up. If you have interest, this is the link to the seat stuff;

https://www.canoetripping.net/threads/light-weight-solo-tripper-build.105054/post-111763

When I add the epoxy, to the joint, I like to saturate the area with unthickened epoxy and leave sit for a few minutes to soak in well, then use thickened to butter the area. Don't over clamp the joint, an epoxy joint required significantly less pressure than glue ... there needs to be epoxy left in the joint for full strength.

You likely already know this, but when there is a failure, likely best to go over everything again to be sure.

Suggestions:
1. lose the top dado/lap in favor of a side dado
2. add a dowel or screw to add support for side rail torque
3. don't over clamp the epoxy joint, think spring clamp pressure or run a screw in the provide the clamping pressure


Brian