RocketFeller
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Our giant Dragonfly is finally getting close to being ready to assemble. The fins are 27" x 10.8" elliptical. They are made of 1/2" Balsasud brand end-grain balsa sandwiched between sheets of 0.066" carbon fiber material from Protech Composites in Vancouver, Washington.
We used three .25" SS pins to keep both of the laminate skins aligned while we assembled the fin. One really nice thing about the composite sheet from Protech is that it is ready for adhesion, no sanding necessary. It has a matte, textured surface on one side and a glossy finish on the other.
After applying Aeropoxy laminating resin to the first 0.066" carbon fiber skin we laid down the 1/2" end-grain balsa sheet. Then we applied resin to the second skin and laid it over the balsa core. Several layers of plywood were used to spread the load of the clamps. We used wax paper covered particle board up against the fin, as it is much smoother and harder than the plywood.
We trimmed off most of the excess balsa on a band saw and then finished the edges on a belt sander.
The almost finished fin. The carbon fiber is still covered with contact paper to protect it during fabrication. The edge is going to have an aluminum strip bonded to it to finish and protect the balsa.
We used three .25" SS pins to keep both of the laminate skins aligned while we assembled the fin. One really nice thing about the composite sheet from Protech is that it is ready for adhesion, no sanding necessary. It has a matte, textured surface on one side and a glossy finish on the other.
After applying Aeropoxy laminating resin to the first 0.066" carbon fiber skin we laid down the 1/2" end-grain balsa sheet. Then we applied resin to the second skin and laid it over the balsa core. Several layers of plywood were used to spread the load of the clamps. We used wax paper covered particle board up against the fin, as it is much smoother and harder than the plywood.
We trimmed off most of the excess balsa on a band saw and then finished the edges on a belt sander.
The almost finished fin. The carbon fiber is still covered with contact paper to protect it during fabrication. The edge is going to have an aluminum strip bonded to it to finish and protect the balsa.
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