Well, I’ve dipped my toe in the water; I made my first cuts and did some gluing too.
As noted above, I brought home a decent piece of Fir—a 2 x 8 x 14’ board. First lesson: bring the metric tape measure with me instead of doing mm -> ft conversion in my head. For some reason I thought I only needed 9 ft of wood, not 11.6 ft. So I bought a board that had about 9+ ft of clear straight grain for about half its width. Once home, I realized what I did and figured out how to get additional good wood from the rest of the board by scarffing bits together. Several rips and cross cuts later, I ended up with two 9’ halves of a boom, and two extension pieces too.
What’s left over will be used for the tiller and for other projects around the house (utility shelves, etc.):
So, it became time to learn to scarf. I figured I’ll have to do some scarfs during this build anyway, so better start getting used to it early. I went about 20:1. I did a rough cut with the table saw, then used a coarse grit belt sander, then broke out the plane. I haven’t drawn a plane over wood in about 40 years, and I was a young boy when I did. So that was an interesting re-learning experience.
I was not perfect, but I believe the rounding of the spar will eliminate the worst of the errors. The next photo is oriented with the mating surface of this half of the spar facing upward. The side resting on the table will become the outer diameter of the boom.
Proof that I did indeed plane. It’s a pretty satisfying feeling when the technique is done right.
Time for glue. I got my epoxy supplies from Duckworks Boat Builders Supply (the agent that sold me the GIS plans and the source of my sail’s Dacron). They sell System Three products and I decided to go top shelf with the epoxy. System Three’s Gel Magic is specifically designed for joining, laminating, and other adhesive applications. It comes in bulk bottles of course (which I did purchase), but it also comes in tubes that accept a mixing applicator tip. Although it’s more expensive per ounce, it also helps cut down on waste. But then the mixing tip costs money too, so it’s hard to say if there are any efficiency gains or is it just a matter of convenience. For the small amount of epoxy needed to join these two scarves, it was a good way to go.
I did dry runs of the clamping before squeezing out the goo, which is what is shown here. I didn’t bother taking a shot after applying the epoxy, since it looked pretty much the same.
It was raining on and off today and we’re just coming off a rainy weekend, so I don’t expect these joins to be cured overnight. But sometime during the week I will join these two halves together (the scarfs will go to opposite ends) and create a square section hunk o’ wood destined to become a GIS boom. Or I might hold off until I have other gluing to do and then hand mix the batches needed.