Here is the repair of my Johnny Bravo rocket. After coming in hard, breaking a fin and some other body damage, I decided that I would rebuild Johnny Bravo. The nose would have to be taken apart and rebuilt and so would the fin can. The body tube was damaged and kinked so I will just replace the entire tube. I may even redo the Altimeter bay so it is in the body rather that the nose cone. I started with the fin can. The tube coupler was the first thing I started on. I used a couple of small straight blade screwdrivers to slowly wedge in between the body tube and the coupler. Taking my time working from the top down and working side to side, I was able to get all the TC out without much damage at all. Then using a Dremel with a shaft extension and a sanding disk, I got the rest of the epoxy out.
The fun started with the fin the had a six way glue point system. Using the cutting tool for my Dremel tool, I cut most of the fin away from the body tube. Then I used a sanding disk and sanded the tin area down to the BT. Now the fun part. I thought of several different ways to get into the BT to finish getting the fin out. Two of the best were using my table saw or using the routing table. I started off with using the routing table. This method got most of the fin out. I lined up the fence and slowly took out as much fin material as I could. This worked except the bit was only so long to reach up inside to clean out the old fin. So I tried the table saw. The blade was just the same width as the fin. Using the same idea I had for the router, I lined up the fence and measured the blade height so it would not come in contact with the motor tube. I also mark a place to stop so I would not go through the upper center ring. Slowly I used the saw with great success. Using the Dremel tool, I was able to get all the fin material out. I still have to do some more internal grinding, but it should work. I received the repair parts and I have started to rebuild Johnny B. I cut the fin out and sanded the edges and test fit it in to the fin slot. Next I epoxied the fin into place. This took a little time. I used 15 minute epoxy on the root edges. and 30 minute for the inside of the body tube to fin contact .With some small holes to feed the epoxy into and tilting the fin can to let it run in. I did this for both sides. Then I did the outside epoxy fillets. Using 30 minute epoxy on them they came out very even and smooth . Then I put the finish coat of epoxy on. Now comes the sanding. The fin can was almost finished when I epoxied the tube coupler on. I still need to fiberglass the fins and paint. The body tube has been glassed and ready for sanding. I'm looking for a way to turn it on my lathe without harming the handy work. I'm still working on that one.
Well after several months and getting past my ex motor phase, I started working on rockets again. This meant to finish Johnny Bravo. After cutting down the body tube (longer to accommodate the altimeter section) I was able to make some end plugs to work on my lathe to finish sanding the BT. I used a bond-O fiber glass mix to get out all the peaks and valleys of the glassing process. Having a lathe to sand, I turned a 4 hour job into about 40 minutes. Once the BT was finished I cut the BT to put in an altimeter bay and constructed the bay using plywood for the end caps. I then drilled all the holes at the same time using a drill press and having both end caps back to back to mirror the holes. U- bolts, t-nuts and terminal blocks were added for ease of use and three altimeter vents holes. I wanted the switch in a place were I could get to it easy so I put it right in the center. This is shouldered to almost fit completely flush with the body tube. The switch is from Missile Works and has a very positive detent and everything is sealed with silicone. I proceed to primer the BT with Kilts (working at Home Depot has its advantages) and let it dry. Then I taped off for the repainting of the BT.
