Catching up

We've been making good progress the past month (at least by our standard).  Nothing too new or groundbreaking, just more of the same you have already seen with the past two beam interiors.  Here is a photo of beam #2 with the gussets at the inner end (bottom of photo) heavily glassed to strengthen this high stress area.  I haven't made any additional progress on the bulkheads in this beam because I am focusing on getting beam #3 assembled and out of the mold by the end of the month.  Then I hope to have beam #4 assembled in January, and the work with the mold complete.  This is in anticipation of a possible move back home next summer, which I would prefer to do minus the heavy wood forms.  I actually never thought it would take so much time to build these beams.  They just have lots of details and they have to be done correctly.

So here is beam #3 in the mold with the initial carbon fiber lamination.  In the background you can see the corner fillets ready to go.  This is the first aft beam, which requires a little less reinforcement than the forward beams.

And now beam #3 has the fillets installed and has been fully laminated with glass.  All that is left to do in the mold is to add the reinforcing laminations, including some carbon fiber and more glass.  Should be done tomorrow then ready to pop out of the mold.  I will also fit the bulkhead foam core before removing from the mold, but that is a pretty quick job.

Here is a close up view of the interior of the recess where the upper linkage with the main hull will be pinned.  This recess will be subjected to lots of stress, especially around the pin, so there are solid GRP plates on either side, which were fabricated a couple years ago when I built the central mounting modules.  There will also be several layers of reinforcing glass to distribute the load to the rest of the beam structure.  The peel-ply keeps everything neatly laminated and is better than sanding, no matter how complex the form.

 Here you can see the three beams in various stages.  Beams #1 and #2 are stacked to the left, while #3 is in the mold.  Note the exterior view of the recess in the bottom (upside down view) of beam #2.  You might also notice the heater working away to the right of the photo.  Temps have dropped, snow has fallen, so now I am trying to maintain progress by keeping temps in the garage warm enough to cure the epoxy in a day or two.  At least I don't have to worry about the epoxy kicking too fast.

To ensure the epoxy is usable, I am keeping it inside in the laundry room closet.  This way it is warm enough to flow and wet out the fabrics.  It does get chilled pretty quickly once it is applied to the cold assembly in the garage, but it seems to be working.  Should get me through the cold winter with fewer excuses for not making progress.

Beamers

 Howdy folks, thought I'd give you quick update on our progress.  We have been working away on laminations and reinforcements in beam 2.  I lost a weekend to a cold, but otherwise made steady progress.  This weekend I finished the internal laminations in the second beam.  Today I cut and dry fit the bulkheads and gussets so they are ready to be glued in place.  Here you can see the seven bulkheads temporarily in place.  You can barely see one of the gussets at the far end to the right of center.  Now I can pull the beam out of the mold so I can start assembling the third beam.

Pull out about a bazillion screws, and here is the newly freed beam #2 along with the first beam (with installed bulkheads as previously discussed).  They look nearly identical, and will even more so once I get the bulkheads installed.  I will glue the bulkheads into beam 2, assemble the foam core for beam 3, and prep the foam core fillet for beam 3 all at the same time so I can make better use of the epoxy putty I will need to mix.  I hate wasting material, so having several tasks that all require the same putty might make better use of the batch.

I should also note that it is starting to get cool here in the northeast.  To keep the epoxy ready for use, I moved the two parts to shelves in the laundry room.  This way the epoxy will be a reasonable temperature so it will flow, rather than being like molasses.  Well, lots of gluing to do, so next weekend should be busy.

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.

More carbon fiber and glass reinforcements

 Last spring, when preparing to glass the beam interior, I decided to precut more of the reinforcements that would be laminated later.  I find I am more efficient if I keep doing the same type of task once set up and prepare materials for later steps.  Now my preparation is paying off as I am ready to install these pieces of material into the beam.  You can see I have both carbon fiber (black) and glass (white) pieces cut and ready to install.  I still use the rolling fabric cutter, and found it works as well on carbon fiber as it does glass.  I also cut some peel-ply, which the rolling cutter doesn't work on too well, so I would have no excuse for not adding peel-ply.

 While the epoxy and glass on the interior sides of the beam set, I moved to the inside end of the beam (the end that will be pressed against the main hull).  This end of the beam is subjected to some major stresses when in use because the float is cantilevered out about 6-ft, pressing this end into the main hull like a nut in a nutcracker.  Therefore, there is lots of reinforcing needed to transfer the stresses to the central mounting modules in the main hull.  Today I added several layers of uni-directional carbon and bi-directional glass fabrics on the inside.  This was somewhat finicky work, trying to work the fabrics under the overhanging fillets.  Plus, it is more difficult to determine if the carbon fiber is fully wetted by epoxy because it is opaque, even when wet.  Nonetheless, as you can see, I got it all laminated in place and covered with peel-ply.  Again, allowing some time for the carbon layers to start to set before adding the glass layers helped keep the lay up neat.  I couldn't add peel-ply to every square millimeter because of the complex geometry under the fillets, but I covered at least 90%.

Once the sides set enough, I was able to pull back some of the peel-ply near the bend in the beam to add some additional glass reinforcement.  You can't yank the peel-ply too soon or you will pull out some of the reinforcing fibers and make a mess.  But I was able to remove the peel ply quickly enough (few hours) for the next layer to form a chemical (stronger) bond with the previous laminated layer.  I also trimmed the extra glass along the edges of the overhanging fillets before the epoxy got too hard.  If you enjoy being stuck by hundreds of glass needles, you can wait for the epoxy to fully cure and then try trimming the edges!  Definitely easier, quicker, and less painful now.

Summer vacation is over … Back to work!

 Hello fellow tri-builders, I am back from extended summer travels, and a little bit of laziness!  Sorry for the long pause between posts. We actually did get the "ski-slope" foam fillets installed last spring, and then glassed over the entire interior.  This was a somewhat frustrating job due to the tight space and small areas the glass had to be worked into.  I tried doing it as a large single piece of glass in the mostly straight section, but I had to split the piece up midway through.  Lesson learned!  Unfortunately I was too tired by the time I finished to try to add peel-ply, so when I finally got back to work over the past couple of weeks, I had to sand the interior.  Again, this was frustrating and kinda slow due to the tight spaces that had to be sanded in the beam.  Peel-ply is definitely a gift from the FRP gods!

In these photos you can see the result of today's effort.  I added a second layer of glass along the sides onto the bottom of the beam interior.  I did divide the glass into overlapping sections this time, and it went pretty smoothly.  I also made sure to add peel-ply, which took some time, but was definitely worth it in time savings later.  I laid the beam on its side to apply the glass around the bottom, side, and fillets more easily, then flipped it over to do the other side.  Rather than rushing and causing myself more headaches, I chose to let one side set for an hour before flipping the form to glass the other side.  I was worried gravity would work against me and cause the glass to droop if I flipped it too soon.  Worked well, gave me a chance to eat lunch.  Here both sides are done and have already set so I could set the beam right-side up.

Next up - more inside reinforcing ...

Ski slopes and carbon fiber

I made a little more progress over the past couple weeks.  The top inside edges of the beams have foam fillets which will eventually provide a good gluing surface for the foam and carbon top plate.  To make the fillets, I glued three layers of regular density foam to make a sheet 1.125" thick.  I actually bought a sheet of 1" foam when I started this project, oh so long ago, unfortunately it is sitting in the boat house in the land of enchantment.  In any case, I then sliced the laminated foam sheet into strips with one side beveled at 45-deg. on the table saw.  The strips were then carefully formed to the top mold to match the curve of the beam.  A layer of glass tape was then laminated to the diagonal edge of the fillet, and extends beyond the fillet edge about 1.25".  A layer of peel-ply was added to ensure good adhesion when glued to the beam sides and top.  This is the new peel-ply I purchased when I stocked up for the beam fabrication project.  It is higher quality than the stuff back home, a little heavier, and it cuts much better (fewer cob webs form along the cut edge). I found this peel-ply is a little easier to handle and place without distorting, too.

 So here are a couple shots of the two fillets setting up on the top deck mold.  Looks like I am building a model of an olympic ski jump facility!  The hardest part of this task was forming the big curve and securing the foam without breaking it.  Because of the triangular cross-section, the foam tends to twist when bent to fit the curve.  So I went over the curved section of foam with the heat gun to make it more malleable, and preformed it while warm.  Then I held the strip in place with screws from beneath every 4-inches, or so, making sure to twist the foam square with the mold.  It worked well, with no mishaps.  I guess Murphy was taking a nap that day.  In any case, the two fillets for the first beam are now cured and holding their shape, as intended.  I will glue and laminate them into the beam structure soon.  Then I will have to repeat the process three more times, once for each beam.

Before I install the fillets, I applied the first layer of carbon fiber to the beam interior.  This roll of carbon has been hanging around the shop since day one, so it is nice to finally make use of it.  It is also a lot more expensive than glass (about 5x by weight), and also a lot stronger (about 3x stiffer) and lighter.  I am keeping all scraps for later use where I need smaller strips.  Since it is unidirectional, I can lay narrow strips next to one another to make a wider lamination without any loss of performance.  To laminate the carbon, I put the epoxy on the foam first and then laid the carbon in the wet epoxy.  Then I used a squeegee to force the epoxy up through the carbon fibers.  This worked very well with minimal foaming due to bubble formation.  I was a little worried about working with carbon because I had read that it is harder to fully wet, but this was very easy and neat.  Being careful not to apply too much pressure on the fibers, I was able to keep the carbon nicely aligned and positioned around the strut recess.

You can see the results of my handiwork in the photos.  I also applied a layer of the quality peel-ply so I can get a maximum bond with the next layers of glass and carbon.  Those layers won't go on until the fillets are installed, after this epoxy cures, so the peel-ply is a must.  And since you probably can't see the peel-ply in these photos, I must have done a good job wetting it out.  This one layer of carbon and peel-ply required 300 mL of epoxy mix.  I should calculate how much epoxy is needed for an optimum lamination. This layer was fully wet, but in no way over saturated, and I had to work to pull the epoxy into the peel-ply, so I think it is pretty good.  The only hard part about working with carbon was marking it, since I can hardly see my Sharpie marks on the carbon black fibers.

Well, that's it for now.  Next task is the fillet installation, then lots of laminating on the inside with both glass and some more carbon.

Foamy and the beam

We are starting to make some real progress on the beams now.  Weather is cooperating enough so I can mix epoxy.  Here you see several hours of work gluing the high-density inserts into the beam sides.  It was a lot of inserts (over 60) and each had to be neatly prepped, glued and adjusted to be flush.  In the foreground you see my 2-part MAS epoxy and hardener in 4-gallon containers.  This plus 4-gallons more epoxy I have in storage should be more than enough for the beams.  The 4-gallon jugs come with both valves, as shown, and hand pumps.  Although more $ per gallon, I do like them for convenience.

With the foam parts all ready for assembly, including sanding and vacuuming for good adhesion, I prepped the mold.  I had already drilled holes for screws to hold the foam parts in place from underneath, which allows me to apply the carbon fiber on top (actually on the inside).  Here you can see the mold covered in clear packaging tape to (hopefully) prevent the epoxy from sticking to the mold.  In the worst case, I have to disassemble the mold to pop the beam out, which is doable thanks to all screws being accessible.  But best case is I remove the screws holding the foam in place and the beam comes out with a little persuasion. In any case, I have the first two pieces of foam in place at either end.  Now it is a race to assemble the other pieces of foam before the epoxy kicks.

And here is the mold with all of the foam parts assembled for the forward port side beam.  I ran out of screws so I had to use every spring clamp I have to hold the aft side in place.  To assemble the foam, I wetted each edge to be bonded with straight epoxy mix, no fillers. Then I applied a bead of slightly thin putty along one edge.  The piece was pressed in place carefully to minimize epoxy squeezing out on the mold side.  Finally I installed screws from outside (underneath and on sides) to hold the piece securely while the epoxy sets.  I did have to install a couple screws on the top side to hold the curved piece in place, so I will fill those holes lightly before applying carbon fiber and epoxy.  I also lost the race with the epoxy and had to toss half of a small batch when it got too thick to use.  But I am mixing smaller batches, either 2, 4, or 6 oz at a time, so less is wasted.  I think I need to add fillets along all edges next, but I have to check the plans to make sure.  That will be the job for tomorrow.

Here is a close up view of the recessed pocket for one of the support struts.  We are looking at the inside of the beam so this recess is inside.  The bolt and nut are holding the solid GRP bolt plates in place with some precision so the folding structure all fits and aligns properly in final assembly.  Lots of little pieces are put together to construct this recess.  Hopefully the epoxy breaks lose of the tape as planned, otherwise I may have a bad day on the way.  Once I add fillets, and the epoxy cures, I will do some final sanding to round over the edges and corners.  This will help the fabric drape the form more easily, making for a stronger beam, and the beams need to be very strong.

Back in a sticky spot, finally

 All right, the icicles have finally melted, and I am done cutting expensive foam board into little pieces.  We are back to work and mixing epoxy.  The first items glued together were the solid glass reinforced plastic (grp) side plates that will support the struts that link the main hull to the beams.  As shown in the photo, the thickening rings were glued to the side plates.  Both parts were fabricated a long time ago when I was making the parts for the central mounting modules.  Each piece is approximately 3/16" think solid glass and epoxy.  To ensure the hole in the rings and plates were properly aligned, I ran a bolt through them while the epoxy cured.  The biggest risk in this step was the parts becoming permanently glued to the bolt.  To help avoid this, I wrapped the bolt with a layer of clear packing tape, which the epoxy doesn't stick to very well.  Then I simply cleaned up any excess epoxy before threading the parts on the bolt.  Since these are high stress components, the epoxy mix included some cabosil to thicken and toughen the glue.  I still need to round over one side of the long edge on each piece, as well as a little general clean up sanding, then these parts are ready to go into the beam mold.

I used the left over glue from the reinforced side plates to start bonding the high density inserts into the various pieces of foam that will make the beams.  There are a total of 16 inserts in the pieces shown here.  Although I still had glue left over at this point, it started to kick and got too thick to use.  I only made about 100 mL, combined with about an equal amount of cabosil.  So it doesn't take much epoxy to do this job.  I covered the table with a sheet of vacuum bagging material, which the epoxy doesn't stick to very well.  Then I just pressed the inserts into their openings, squeegeed off most of the excess epoxy, and evened it up on the table.  Once cured, the parts popped off the table with minimal persuasion.  Before assembling these parts into the beam mold, I will sand both sides clean.  Easier and quicker to do the sanding now than when assembled into a complex form with lots of inside corners.

These parts are the foam pieces for the beam sides, including all 72 high density inserts.  I spent the past couple weekends custom fitting each of the inserts so I could glue them in place efficiently.  Each piece is labelled so if I drop the stack I can figure out which insert goes where.  Next good weather day, i.e. reasonable temperature and moderate humidity, I will permanently bond the inserts in their respective cut outs.  Then a little sanding and ready for installation in the beam mold.  I could have installed all of the inserts when assembling the parts in the beam mold, but I figured it would be easier and less stressful to separate the tasks.

I still need to do a little prep on the mold before starting assembly of the foam.  Some of these tasks include drilling holes for screws to hold these parts in place until they are bonded together, and marking and taping the seam locations to prevent gluing the parts to the mold.  Hopefully old man winter has gone to bed, and the spring showers cooperate so we can get on with the fun.

Slicing and dicing

We received all of our supplies to proceed with the beam construction, including gallons of MAS epoxy with slow hardener and several sheets of CoreCell foam.  The weather has been particularly cold and damp, so I am not in a rush to start work with the epoxy.  When temperatures rise enough for my 1500W space heater to keep up in the garage, I try to make progress by pre-cutting the foam as needed for the beams.  Here you see all of the high-density foam inserts that are required for the four beams.  This is CoreCell 1200 (~12 lbs/cf).  It is much harder than the CoreCell 500 or 550 I use for the majority of the structure.  As a result, cutting takes a bit more time and effort.  I cut all of my foam with a knife rather than a saw to minimize waste.  This stuff is just too expensive to turn it into dust.  In any case, it took me about 4 hours to cut all of this, including time to figure out all of the dimensional details.  I think I have less than a few percent waste, so that is good on the budget.

Here you can see the foam starting to be fitted into the beam mold.  The foam along the bottom of the mold is just being dry fit for size.  Most of the foam seen here is standard density foam, except at the two ends.  Once all of the foam parts are cut, including cutouts for he high-density inserts, I will start epoxying them together and then the real build begins.  The wedge in the middle of the mold (upper left in photo) will form a recess in the beam for part of the beam folding mechanism.  I finished cutting the foam bits that encase the recess last Monday during a brief warm spell (I think it hit 30 F!).  This weekend I plan to finish cutting the foam for the sides.  I will also try to cut the foam for the top of the beam which is formed on the other mold to the right in the photo.  Hopefully Mother Nature will cooperate and give me some warmer weather so I can start mixing epoxy soon.

Building beam molds

 Happy 2014!  New year with new progress on the F-82R.  Here is a view of my new boat fabrication factory.  There is just enough room to lay out a 4x8 sheet of particle board, if I suck in my gut!  Nonetheless, I was able to assemble the three molds and stands needed to build the beams.    The one that looks like a skateboard ramp on the right is for the beam tops.  The box on the table is a support stand for the beams during fabrication.  The main beam mold is on the floor in the middle of the picture.  I also had to get some new tools since most of my power tools are also back home.

Here is a picture of the main mold for the beams.  The main side panels had to be recut since the originals are still at the "main factory."  The spacers and other bits were shipped (I am sure it would have been more economical to recut everything).  In any case, it all went together very nicely.  Now I just need my supplies to arrive from Noah's and I will be back to boat building.