I broke it ;oD.

Rather than wait overnight, I thought I'd go down and put some weight on it. It held. I flipped it over a few times, putting more and more weight on it. Sure enough, it broke. Took quite a bit of weight, and there was a lot of flex to the board, but it did break. Like you say, the joint wasn't completely good. The side of the joint that was near perfect was fine. You can see where the wood tore before the Gorilla Glue did. The other, with that slight gap... not so good. There was no wood/wood contact in that portion of the joint. The GG didn't even foam in that area. That makes me wonder if I spread it too thin in that area, or if it never made contact with the wet side of the joint and therefore never foamed, and the cured coat is simply too thin for me to see.

I figure I have two choices for the cut: become much more proficient planing (practice makes perfect!) and more fussy with the joint itself; rig up a jig for my circular saw. I'm not a fan of the circular saw, as I've stated in the past... I much prefer hand tools for precision work. I'm not sure how good a cut I can get with a jig, which may be part of my hesitation to use the circular saw.

If Titebond 3 will give me some "wiggle room" in the quality of my joint, I'd be happy. The temperature in my basement workshop has to be around 50-60 degrees. judging from my desire to wear a long sleeve shirt when I'm working. I'm leery of using epoxy 'til the weather warms it up, regardless of its gap filling properties.

For the time being, I'll probably recut this joint, and practice on it a bit 'til I get the knack of perfecting that joint. Might even build a jig for my block planes, since that should be easy to do. Seein' as the GG worked on half the joint (the wood split first), I'll probably stick with it, assuming I can get get good joints.

There's more pics of the failure up on my Picasa album...

https://picasaweb.google.com/theluckyone17/Kayak#

: I have cut and glued many scarfs in stringers. Every one of my
: boats has several scarfs in them. It's just normal for me. I
: can't find good lumber so I cut out the knots and scarf them
: back together.

: Dowels are not needed if you do the joint correctly. I use Titebond
: 3 and no failures yet. But I use a jig on the tablesaw and get a
: perfect mating joint. You said you didn't have good mating
: surfaces. No glue I know of except epoxy is very good at filling
: gaps so if I were in your shoes I would use epoxy.

: My scarf joints just fall anywhere along the stringer and have
: never worried about where they fell. Of course 'Your mileage may
: vary.'