For easier sanding, the card stock overhanging the fin frames got a coat of medium CA glue.
I didn't cover the entire fin covering, just a little beyond the overhanging edges.
This stiffens up the card stock for easier sanding and removal.
When the card stock is sanded thin it will fold over a little.
I started with 220 and finished up with 400 grit.
Sand to the balsa sides, don't sand so much as to thin the frame sides.
Here's all three upper fins sanded and ready for sealing.
Look close and you can see some of the sanded card stock edge still rolling over the sides.
Those fins you built in step 6 will need reinforcement. The way I do this is to drill a tiny hole thru the fin root and inject with a capillary tube attached to the tip some super-thin CA to coat the entire inside. Let it dry normally without accelerant. This step will strengthen the units so they won't be as prone to twist or deform as the rocket lands on its side under chute. The Estes Saturn 1B fins built this way last a lot longer, too. Coating the inside makes finishing with paint easier, as well.
ReplyDeleteI am enjoying your build. In spite of some comments, these are great kits if you are prepared to make some improvements as you go. TLP's Nike Hercules is the same, with some scale mistakes one needs to fix for it to be 'right.'
To me, that's part of the fun!
Allen
I have already coated the outside with thin CA and it really stiffened things up. I don't know if an interior coat could make it any stronger?
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