Scarf Joints Revisited

I finally got a jig built for cutting my rails. Now I am wondering what is the best way to clamp them when gluing them up? I have a variety of clamps to play with and plan on dry fitting first. Any suggestions from the experience out there? Many thanks.


Free of the boat?
If so, you can clamp them to a board with wax paper as a barrier to keep you from glueing the pieces to the board along with each other.

I only did it once …
But I used a thin strip of wood on the top and bottom (like a splint) to keep things lined up. Then I glued with Gorilla glue, put the pieces together and then wrapped everything tightly with a long 1" wide section of bicycle inner tube. No issues other than Gorilla glue cleanup with a wood chisel and some sanding. Has held up well for around 5 years now.

you could try G-Flex
I have glued up ash a number of times now with G-Flex epoxy and really like it. No excess mess to clean up as with Gorilla Glue and the honey color does not detract from the wood.

I would clamp both pieces of wood to a long bench or board with a piece of plastic wrap under the joint area. The clamps will keep the two pieces from trying to separate when the joint is weighted or clamped. I would probably have the inclined surfaces of the scarf oriented horizontally, but you could orient it the other way. After applying adhesive clamp or weight the joint itself.

You could also use a couple of furring strips along the sides of the joint (with plastic wrap between them and the gunwale pieces) to keep the joint aligned.

The pre-scarfed gunwales from Eds
have screw holes drilled so screws can clamp and keep them in alignment. I haven’t tried them (yet) but I think that system would save some clamps.

Agree with G-flex
Also, use wax paper and thin strips of wood between clamps and wood being scarfed. Also consider the location of the scarf joints on the boat. I had some scarf joints fail that were located half way from the ends. This may be the point of much stress, especially when two people pick-up the boat. The next boat I built I put the scarf joints more toward the ends, off-set them one on each side, one at each end. Seems to be working

I use type III yellow glue. I built a quick fixture with a smooth surface, and a back fence at 90 degrees. It is longer than the joint. I lined it with waxed paper, and clamped it in 2 dimensions with cauls. 24 hours, quick clean up, good joint.

Good Suggestions
I had read an article where they say drill and put a finish nail part way in to hold the joint. I’m not to fond of that idea but can absolutely see the logic in it. I’m all to familiar with the wax paper app from the rebuild of my Courier and it works great. I’m going to be messing around with this this weekend and will try the ideas out. Gotta love dry fits and being cautious!

Thanks all.


I used regulalr C clamps
with a 1 to 5 angle and epoxy thickened a little bit. The join is still good after 8 years. Do not

crank down on the clamps if gluing epoxy, just snug.

Over all the join is 2/3back on the outwales and 2/3

forward on the inwales.