2 replies to this topic

[Noklin]

I need to make up some rub rail material for my Core Sound 20. Rub rail will be painted.

If I do a 8 to 1 scarf in material that is 1.5 inches wide and 0.75 inches thick, I end up with a joint 1.5" X 6" or 9 sq inches of glue area.

If I do a 8 to 1 joint in the same material but cut across the face of the material, I end up with a joint 12" X 0.75" or 9 sq inches of glue area.

One upside is that the second joint is easier since I can clamp the two pieces together, overlapped by the length of the cut and cut both at once. The two pieces with be a perfect match to each other. Down side is that I lose a foot of length and the joint is visibly much longer.

I may not be using the correct terms here but hopefully you can understand the questions:

Since they have the same glue area but one joint is across the face and the other is along the edge, which is stronger and by how much?

Will they both take the same bend?

[Frank Hagan]

Well, if you're going to paint it, I don't think you have to worry about appearance as much.  So do whichever is the easiest to do.

An epoxy glue joint is usually stronger than the wood itself, and I suspect either one would be strong enough for a rubrail.  You may get problems with breakage depending on the grain of the wood, but that can happen at any point.  I did have a scarf joint give way when bending the wood ... it sounded like a rifle shot!

[GPorter]

You may find it much easier to forget the scarf joint and just but sections together with something like a 45 degree cut.
Use something like 5200, 4200, or even epoxy to make a nice fill in the joint.  Double screw the pieces close to the joint.
Gary