Sunday, February 18, 2018

3/4 of a keel

Lamination work on the keel has begun.

I started with the big 4" wide chunk of mahogany, mentioned in the last post. It was 4" wide, 2" thick, and 9' 10" long.

The plan was to re-saw this board into 3 smaller boards, each approximately 1/2" thick. I would then (a) cut a short 3' section off of one of these boards, and butt-join it to one of the longer ones. I'd then (b) take the longer leftover cut, and use it to back the butt joint.

This would leave me 3/4 of a keel, with the thicker section on the aft portion. Since the forward section would temporarily be thinner, it should (c) be easier to bend, as needed, into the keel notch of the breasthook when attaching the keel to the frames.

Once this is accomplished, I would (d) laminate the remaining needed thickness onto the forward section of the keel.

My re-saw job on that big chunk of mahogany was less than perfect. I set my rip fence to cut a 3/4" wide strip. I knew I'd have to plane some surface irregularities from there, and I did. Two of the finished pieces were 5/8" thick when I deemed them "usable." In retrospect, I wish I'd planed them down a little further in an attempt at better fitting.

The remaining, "leftover" board is closer to 1/2" thick... or maybe even a little less. 

Due to some width irregularities, I shortened the 9' 10" length down to 9 feet. The Zip plans call for a 4" wide x 1" thick x 12' long keel.

So, where are we now? As you might have guessed from the title, we're at the point of having 3/4 of a keel. Let's take a look:

Sometimes, you just don't have enough clamps.

Somewhere in the middle of all that is the butt joint.

Butt joint and backing plate.
I used System Three Silvertip epoxy, thickened heavily with mahogany wood dust. I knew the fitting between the laminations would be less than perfect, so I wanted a good thick mixture to fill in any gaps. 

After the epoxy cured and I pulled the clamps off, I saw that some of those gaps had been bigger than I thought. Since the thickness of the laminated keel is now at almost 1-1/2" inches, I realize now that I could have safely planed away more surface irregularities and still made my goal of 1" combined thickness.

At the time, I stopped planing at "usable" because I feared the wood was getting too thin. 

Live and learn.

Ah well, epoxy-filled gaps or not, this is the keel, and I'm moving forward with it.

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