Mainsheet Beam Cores Finished

 I spent several hours working to shape the laminated fir blanks.  The first order of business was to create an MDF template of the shape off of the drawings.   This required lofting a few points onto the MDF.  I then pulled a batten in line with the points against small nails. Next I hot glued the batten with support blocks to the MDF.  I could remove the nails and trim away excess material from the MDF sheet.  I then took the batten and MDF to the router table where I used a flush trim bit to cut fair curves.  This seemed more accurate than trying to sand fair curves to a line, especially on the concave side.

The batten flexed across nails.

Once the template was finished, I attached it to a laminated blank.  Using a saw and a belt sander (I still don't have a jigsaw), I removed excess material.  I then trimmed the blank to match the template using a 2 inch flush trim bit.  Almost all the excess has to be gone before using the large flush trim bit given the large load on the router when trimming over an inch and a half height (40mm) at once.

The finished template attached to the blank.

The blank cut and sanded close to the template.

With the blanks the correct shape, I moved on to rounding over the edges.  This is for aesthetics as well as getting carbon fiber to bond over the edges.  I also cut "nubbin" slots at each end.  These will keep the lashings that hold the blocks to the beams from slipping.

Finished cores after trimming, rounding over the edges and adding nubbins.

These are now ready for the first layers of carbon uni.

Task time: 6 hours

Total project time: 294 hours