Tuesday, February 28, 2012

Formula 75 - the fins are in!


The fins have been installed in the rocket. The image above shows some water drops inside, the whole thing was cleaned after a final sanding. After the parts were fully dried, the fins were tacked on with CA, and secured initially with a small application of JB weld. A pour of 5 minute epoxy was used on the centering ring to hold it in place and get epoxy rivets going through the lowest fin holes that I drilled. Slowly, with a 24 hour curing time, JB weld fillets are being used between the fin and motor mount. These will see the worst of motor heat so JB weld is a good idea. For the fin to airframe internal fillets, I will either use 5 minute epoxy or 30 minute epoxy. Strength matters here, but heat exposure is minor. Once this is done, the rocket will be ready for foam, and the centering ring will be installed.

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