Longitudinal webs

While working on the foam fillets for beam #2, I also continued work on the bulkheads in beam #1.  Here you can see the longitudinal bulkheads (or webs) that have been glued in place between two pairs of bulkheads.  I also glued a small longitudinal stiffener at the outer end (bottom of photo) that will help strengthen the attachment point between the beam and float.  (In case you are confused by this photo, beam #2 is still in the mold underneath beam #1.  It is convenient to set beam #1 on top of beam #2 while working on other tasks.)

Today I sanded the glue joints and then added putty fillets along the edges of the longitudinal webs.  In this photo you can see the nicely filleted web that will strengthen the bend in the beam.  Next I will glass over these webs in the same way I did for the bulkheads, and be one step closer to complete.

Possible toboggan runners?

 Once again I am fabricating the top inside edge foam corner fillets, this time for beam #2.  As before, it still looks like something related to winter sports when on the mold.  But I have no intention of sailing in cold weather, so the likeness is only coincidental!  The hard part of fabricating these pieces is bending the triangular foam section to fit the curve of the mold without twisting.  Last time I tried just using the heat gun to convince the foam to bend into the desired shape, which worked okay.  I still had to struggle to prevent it from twisting, and ultimately had to sand the edges square.  This time I tried something different (see below).  As before, I applied peel-ply to the glassed side of the fillets for better adhesion with less effort when I glass the interior of the beam. I chose to not peel-ply the top edge (on bottom between the mold and glass tape in this photo) this time because I felt the peel-ply distorted the flange too much.

 To bend the fillet this time, I tried kerf cuts in the top (narrow) edge of the fillets.  This allowed the foam to bend along the uncut bottom edge while the top of the triangular section closed the kerfs.  I made cuts every inch through the top 5/8-inch of foam.  Here is a photo to help clarify my description.  I used a hacksaw blade to make relatively wide cuts, giving the foam room to compress.  Only about 16-inches of the fillet needed the kerf cuts to take the shape of the mold.  I had to be careful when handling the cut foam since the cuts provided convenient fracture points (I only broke one of them, but nothing that epoxy can't fix!).  Then the fillet just dropped right into the mold with hardly any struggle.  And most importantly, there was no twist induced using this technique.  When glassing, I made sure I got plenty of epoxy between the kerf cuts to help hold the form of the fillet.  I will definitely use this method on the next two beams as well.

 And today I installed the fillets on beam #2.  I think these fillets came out much nicer.  The GRP flange is much more uniform and has a better shape that follows the top edge of the beam nicely.  Since the molded glass flange wasn't peel-ply'd on the outer face (now facing up and out), I will have to sand it prior to gluing the top on the beam, but that is easy to do.  A small price for a better formed flange.

And here is a view of the with the fillets installed from the other end.  Next step on this beam is to laminate the interior with glass.  Then a second layer on the interior sides and lots o' reinforcements.

Twins!

 No, this is not a repeat photo from last winter.  I am finally assembling the second beam (forward starboard side)!  I pulled the first beam out of the mold last weekend (see below), and installed the foam core for the next one.  Today I laminated the first layer of carbon fiber with peel-ply along the bottom of the beam interior.  This is the easy part, and it was nice being able to reach all corners without twisting my wrist like a pretzel.  From here on, it gets progressively more cumbersome with the addition of the corner fillets.  I'll start preparing the corner fillets next week.  And I expect this beam will come together quite a bit faster now that I have done these steps once before.  Maybe I can have all four beams out of the mold by New Years (I know, I'm slow … or maybe just overly optimistic!)

And here is the elder twin free of the mold at last. It popped out of the mold with little effort, just a couple sharp bangs on the mold to break loose any epoxy that squeezed through and it was out.  All interior reinforcements have been laminated, and I installed the bulkheads last weekend.  Now I am laminating the bulkheads, which is tedious, though not too difficult.  In the photo below you might notice the drain holes in the bulkheads to ensure no moisture or pressure builds up in the beam.  Some day in the future, there will be drain holes in the outer end (on right in photo) that drain into the float.  After all of this detail work, I would hate to have a beam rupture once it is closed up.

Here is a view of the inner end of the first beam showing one of the bulkheads and the gussets (at the top of the view).  Laminating multiple layers of glass around the gussets was also tedious and picky work to keep the glass in good contact with the foam core.  You can see the edges of the multitude of peel-ply pieces used to finish the lamination.  Technically I don't need the peel-ply since there is almost nothing left to glue to this area, but I like how the peel-ply holds the edges of the glass together and creates a cleaner finish (that no one will ever see!).  In these complex geometries, I have to be careful that my attempts to apply peel-ply doesn't disturb the glass underneath, producing bubbles in the lamination.  I still have to  finish laminating the bulkheads (2 out of 5 complete), then add a couple longitudinal bulkheads and laminate those, add a hardwood reinforcing block where the beam bolts to the main hull, and add the aluminum backing plates for the wing nets.  Then I can focus on the exterior finish.  Sounds like a lot, but should be done in a few weeks.