Saturday, September 29, 2007

Fillet and Tape

The construction of Dragonfly has now progressed to the "glue" portion of "stitch and glue" boatbuilding. First, a final check of the hull's alignment showed that everything was in place. Using a technique called "winding", the hull was checked for twist by placing two straight pieces of wood across the sheerclamps, and then sighting down the centerline. With the two pieces of wood superimposed, the hull showed no twist. The point of the bow and stern were plumb, and all appeared in readiness to permanently joint the parts of the hull with epoxy and fiberglass.

The first step is to apply a fillet of wood flour thickened epoxy to the joints which will provide a smooth radius for the fiberglass tape to come. The epoxy is mixed t0 peanut butter consistency, which makes it reasonably easy to apply with a wood tongue depressor, then smooth with a rubber spatula cut to the appropriate radius. The only difficulties I ran into was the fillet on the joint between the sheer panel and the bilge panel. Near the stern, this joint had almost no angle (or a 180-degree angle), which made a clean fillet more difficult.

With the fillets in place, and before they cured, I overlayed them with strips of 3" wide fiberglass tape. The tape was then wetted down with unthickened epoxy to form an integral, strong joint. At an ambient temperature of 85 degrees, the slow-cure epoxy is setting up fairly quickly, so the boat is done in sections; today I did the stern behind the aft bulkhead. Tomorrow- the bow and center compartments. Total hours: 11.75.

1 comment:

Jorge said...

Form Argentina, following your work. Excellent!. I am fun of wooden boats, and I am reading from some time the techniques of construction. Unfortunatelly, I do not have time to build my own (up to now...) but for sure one day I will. Thank you very much for sharing your work. Jorge