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A template of the fin design was created by drawing an outline of the fin on some heavy poster board type cardboard. The cardboard template was then cut out with an Exacto knife.  This photo shows the white template laying on top of a sheet of green G-10 fiberglass.  A ruler is used to give some idea of the scale.  These fins are fairly large!

A fine point Sharpie felt tip pen was then used to trace the outline of the template onto the sheet of G-10.  We are now ready to cut out the fin.

I use an industrial jigsaw blade with carbide teeth for cutting G-10.  This blade is made for cutting stainless steel or Corian but works really great for G-10 too.  It is made by Vermont American and is part number 30003. It can sometimes be found in local hardware stores, but can also be purchased at an online hardware store at www.doitbest.com for about $14.  Their SKU number is 390801 for the 18 TPI blade and 390798 for the 24 TPI version.  I prefer the 18 TPI (teeth per inch) version since it makes very quick work of thick G-10.

A sheet of G-10 is clamped to the top of my Black&Decker Workmate platform while I use a handheld  jigsaw to cut around the outline of the fin.  Don't forget the dust mask! 

One done, two to go.

The G-10 fins need to be sanded to round over the leading edges and to remove the glossy finish so that epoxy and paint will stick to the surface.  I use a 100 or 150 grit sandpaper on a palm sander.  My workshop is in an unfinished basement and the sanding platform is positioned next to a window with a fan installed to pull all the G-10 dust away from me and exhaust it outside into the basement window well.   I hate sanding, but this makes it reasonably quick and convenient.   A dust mask is still a good idea too!

The three fins are sanded and ready for assembly.

This is the fin positioning fixture that I use.  It is a simple assembly of some wood pieces on a plywood base.  I use the clamps to hold the fins to the upright pieces.  The motor tube fits over a centering ring in the middle of the fixture.  This fixture will hold the fins at the proper angles and keep them aligned while the epoxy cures.

Once everything as been aligned, then the six outboard motor tubes were removed, and the centering rings were epoxied to the central motor tube and to the fins.  After that the fin roots were epoxied to the central motor tube.

The fin root was epoxied to the central motor tube using some strips of fiberglass cloth.  To begin this process I first wetted the root of the fin and the motor tube with West System Epoxy.  Then I pushed some fiberglass cloth strips into place and allowed the epoxy to saturate the cloth.

This shows one of the 8-ounce fiberglass cloth strips being put into place.  Brushing it lightly with a small epoxy brush will seat it into place and thoroughly wet it out with the epoxy that is already on the tube and the fin.

Once all the fins have been epoxied to the central motor tube, we can re-install  the six outboard motor tubes and epoxy them into place.  One thing to remember here is to recess the ends of these tubes into the rear bulkhead by the correct amount.  They should not be flush with the end of the rear bulkhead.  They should be recessed to allow the motor end closures to sit flush with the rear bulkhead.  Some small wood blocks (not shown) were used to hold the six outboard motor tubes at the proper height while the epoxy cured. 

Letting the fixture sit overnight to allow the epoxy to cure.

Once the epoxy had cured, the assembly was removed from the fin holder fixture and the bulkhead at the forward end of the fins was then installed. I actually turned it upside down (not shown here) to apply the epoxy on the fins and motor tubes at the forward bulkhead.  I even left it that way until the epoxy cured.   That made sure I didn't have any epoxy runs down inside the motor tubes that would create an interference with the motor cases.

The body tubing has fin slots cut into it so that it will slide over the fin can. 

Here we do a test fit.  It is starting to look like a rocket!

We are now ready for painting!