After the lengthy design phase it was time to manufacture the bulb. Some styrofoam was glued to blocks on a MDF board, these blocks were then milled. In order to obtain a usable surface the styrofoam was sanded, saturated with epoxy resin, again sanded and given a second coat of resin. Mold release wax was then liberally applied.
To reduce the necessary laminate thickness we used exclusively carbon fibre. The two shells were laminated and let cure in the oven. To protect the laminate from the high temperatures of the liquid lead, a coat of resin with very high content of Poraver was applied.
The shells were then removed from the molds and a channel was cut, by hand using a dremel, in the lower mold half. Once attached to a garden hose, water would flow past the shell cooling it during casting of the lead. This technique proved to be very effective.
The two bulb halves were then united and the seam was reinforced. Next threaded tubes were installed at the top and bottom of the keel, then the keel was filled with epoxy resin with foaming agent. Controlling the exothermal reaction proved to be quite challenging and the keel was filled at about 30 cm per time.
The bulb is attached to the keel with four M8 screws, a 10 mm 6060 T66 aluminum plate is attached to the top of the keel with five M8 screws, this plate rests on the deck.
The keel is now installed in the StarTruc22. Stay tuned for news regarding the launch!