Saturday, January 17, 2015

Scarfing

After a suitable period of deliberation and study (not to day hand-wringing and self-torture), I decided that I had to get the gunnels, breasthook, and knees right, or as right as I could get them at my current level of expertise. These are the most visible bits of joinery on a boat, and its said that you can judge a boatbuilders skill just by glancing at the way they all fit together. To leave them the way they were would be like saying "I just dont care." And I do.

Actually, the gunnels themselves were fine. Or were fine until I over-clamped one end, trying to force it into shape. There must have been a small defect in the oak, because I broke off a corner. Most frustrating.

My goal was still to refit Cabin Boy using wood I had on hand. Im trying to preserve my limited building budget for the Blue Moons cabin build. Unfortunately, I didnt have another 10 long piece of oak. This stymied me for awhile, until I realized I could simply scarf back on the 2 foot hunk Id imprudently cut off a few days ago. A bit of a pain, but Id get to practice my scarfing skills.

Id been reading one of the best boatbuilding books Ive ever found, Walter Simmons "Lapstrake Boatbuilding". This book has a very useful hint on how to easily find the right angles for a scarf.

Trick to Align Scarf Joints
From Walter Simmons "Lapstrake Boat Building"
I saw that illustration and thought "Hey, I can do that!" That is the sign of an excellent illustration and book, I think. I cant recommend this book high enough.

Here are those simple lines on my two pieces of oak. I started to cut and then realized Id forgotten to take a photograph.

Angles marked off on gunnel and extension
I made the cuts on my bandsaw and then finished the joint off with a wide chisel. Here they are laid side by side before gluing.

Cut out and trimmed

Although I complain about epoxy from time to time, theres no doubt epoxy is perfect for scarfing. Some will say epoxy doesnt work on white oak, but if you read the West System manual, youll find this is not true. You just need to make sure the surfaces are roughed up a bit with sandpaper and, if you are the cautious type, wiped with alcohol.

Glued and clamped
Heres the scarf glued and clamped. Ive got plastic wrap around the glued gunnel, to keep it from sticking to the table, and Ive got an extra piece of oak on either side, to spread the clamping pressure. As alway with epoxy, you dont want to clamp too hard. You need to leave the epoxy in the joint, and not squeeze it all out.

The next day, I just gave the gunnel a light sanding to remove the excess epoxy. The results were quite alright, I thought.

Finished scarf
So, the next step will be to fit the gunnels and then spile out the shapes for the breasthook and knees. Stay tuned!


Next Episode: Bevels, Bevels, Bevels

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