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

Mainsheet Beam Progress

Both of the mainsheet beam laminations are done.

Here are the beams after coming off the mold.

Here they are after sanding and planing them flat to a 40mm thickness.

Next step is modifying the upper (concave) curve and shaping them.

Task time: 3 hours

Total project time: 288 hours

First Mainsheet Beam Layup

I ripped some Doug Fir for the mainsheet beams.

I went with wider 7mm boards to try and reduce spring back after unclamping.  The thicker laminates put up a fight when tightening them down.

The layup is molded to the lower more gentle curve.  The top asymmetric curves will need to be cut with a bandsaw later.

The beams run athwart the main hull as shown in the picture.  There will be a block lashed to each end.

Task time: 7 hours

Total project time: 260 hours

Aka Laminations Cleaned up

When the laminate beams for the akas came off the jigs there were pretty messy with squeeze out.

A cleaned up beam next to a raw one.

Longer view.

It took no small amount of chiseling and long boarding to get back to the wood.   The beams were then planed to a height of 58mm.

This is a shot of the finished beams with a coat of epoxy on what will be the inside faces.  These are the only sides that won't be bonded to, so I thought I should seal the before continuing.

Task time: 15 hours (last 3 days)
Total project time: 126 hours

First Pair of Aka Sides Laminated

I spent the first part of the day ripping fir into 1/8 inch strips. These are about 62 mm wide and will get narrowed to 58 mm after lamination.

Next came a layup of 4 or 5 strips.  I had ended up with a couple strips that were 1/4 inch or a little more.  I could not get them through the table saw one last time since they were too narrow to push. The thicker strips bent nicely along with the 1/8 inch stock.  The layups needed to be 19 mm.  Since I could not hit 19 mm exactly they are a couple millimeters larger. This should not cause a problem in an area that could use a lot of strength.

There was a second layup for the other side of the first beam.  After un-clamping tomorrow, I'll do a second pair.