Curved Panels for Pod and Cockpit

I have been bad about posting.  I started working on curved foam panels back before the holidays.

The pod and cockpit are assembled out of curved foam sandwich panels.  Most all parts that are above and outbound of the deck are divinycell cores with two layers of carbon on each side.  The external side gets an additional e-glass layer for durability.

Paul designed these appendages so that all of the sides use the same curve.  This greatly simplifies the building.  All seven or eight panels can be layed up on the same mold.

The mold was build out of three CNCed pieces of MDF that define the curve.  These were joined to a base plate and some lightweight supports were added.

The tool face is two sheets of 1/4 inch melamine glued down to the structure.  I added screws along the edges to strengthen things a bit.  There is a seam between two sheets of melamine that needed to be fairly smooth and airtight.  After pondering how to seal this, I settled on about five layers of overlapping packing tape.   The whole surface is waxed and has some mold release as the outer coat.

Panels are vacuum bagged to the surface.  The layup is either a two or three step process.  The best inside finish is obtained when the inner skin is cured separately from the core.  The core can be laid over the the inner skin in one step, but thickened epoxy used to fill the foam surface can be forced through the carbon clouding the finish.

In either case, excess cloth needs to be trimmed from the inner surface using the core as a guide for a router before adding the outer surface.

Here, the inner skin is laid over some peel ply.

The core is being bagged to the inner skin.  This panel is the leeward side of the pod.

I'll show more pictures in future posts.

Cabin Parts

Areas of the main hull that are above and outboard of the deck are made of composite panels.  The panels are divinycell covered with carbon and an outer skin of fiberglass.  Some of the panels are flat while the majority are curved.  One curve has been used for all of the panels so that the builder only needs one mold.

I had mold frames cut at Turnpoint Design out of MDF.  Using a CNC ensures the frames are identical and also had the side benefit of adding puzzle joints.   The mold surface is about 12 feet long, so the puzzle joints make it easy to connect the fairly large sheets.

Three frames will be anchored on sheets of OSB perpendicular to the shop floor.  The too face will be two sheets of 1/4 inch melamine attached across the mold's top curved edge.

The plans also call for a laminated beam to support the curved foam cabin top.  The line for the beam can be taken off of a  mold as shown above.


Prior to starting on the curved parts,  I have been assembling flat panels.  I can use a sheet of melamine on top of my work table while it is still flat.  Flat panels make up the cabin dome and the bunk.

This photo shows two pieces of foam that form the dome top.  I perforated the foam in a one inch square pattern to allow air escape in the vacuum bag.  I need to make a perforation tool that pokes more than one hole at a time.  Presently I used a cordless drill on matching panels that are clamped together.

A layup of 2 or three layers of fabric is done and then the sandwich is clamped to the melamine.

This is a fuzzy shot of an untrimmed panel coming out of the bag.  The outermost layer is fiberglass to add a little toughness to the skin.  The glass is visible across the window and on the edge.

I trim the excess cloth off the edges and then cleanup using a flush trim router bit.  The pattern is the part's twin clamped to the working piece.  Some parts don't come in pairs, so I'll have to use a batten.

This shows a cross section of the fir cabin beam molded off of the jig above.   The beam is 9 feet long and 30 x 50 mm thick.

Task time: 65 hours

Total project time: 919 hours

Ama Progress

The ama has been making good progress.  The keel panels went on.  Next the seams got cleaned up and filled where the wires had been.  The wire holes were closed.

A main task before moving on was fairing the chines, bow and keel.

Here is a bow filled and capped with a thin strip of glass.  I wanted to fully close the seam.

The bows and keel were about 20mm wide when joined.  The square shape did not look too sleek, so I decided to add a foam nose piece. The top picture show the foam glued over the glass, while the bottom is after shaping.  This is Divinycell H80.  It is strong, though I worry about cosmetic damage in minor bumps.

On the keel, I used the same concept with a strip of plywood.  The plywood has the corners on one edge rounded over.  A thin bullnose was then ripped on the table saw.  #17 finish nails are place prior to gluing.  The nails will act as alignment guide once the strip is wet.  Tape at 2 inch intervals worked pretty well as clamps.  I used fast hardener and added a little 5 minute epoxy to get the glue to stick and kick faster. This is a trick off of the West System site.  Sanding then faired it into the keel panels.

Here is the glass draped and partially smoothed.

The intersection of the bow and keel fairings.

The cloth has been wet out with a roller.  This shows how the bulkhead tabs were glued to the hull panels.

Here is the hull drying prior to the first fill coat.  The skirt will be trimmed off of the shear before the epoxy fully cures.  The skirt is also handy for catching epoxy runs during wet out.

Task time: 50 hours

Total project time: 660 hours

Fairing Stay Bulkheads

I decided I would fair in the cplate braces on the fore/aft stay bulkheads.  This would give it a little more finished look.  I added small strips of divinycell along the edges.

You can also see a flaw on the line to the left.  This was caused by using a piece of peel ply with a crease in it.  If you buy West System peel ply, get it bulk in rolls, not folded in bags.  Fiberglass Supply has a similar product in rolls.  It is impossible to get the creases to lay flat.

Once the epoxy was set, I sanded a bevel onto the foam.

There will be one light, cosmetic layer of carbon over the top.

Task time: 2 hours

Total project time: 304 hours

Got Wood?

I picked up the plywood and foam from Turn Point today.  It looks more like a giant Ikea purchase gone wrong at this point.

That is about 95% of the hull in the back of the pickup.  

Side view in the shop.

The Divynicell is cut as well.