Neutronium95
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- Joined
- Jan 17, 2010
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I have a few high performance designs on the horizon, so I figured it would be a good idea to learn how to make my own tubes. I also have an old midpower rocket built out of a bunch of BT-80 tubes that eventually had to be retired due to fatigue, so I'm going to clone it in carbon as a learning experience. I would appreciate it if some of the resident experts could review my ideas before I waste a bunch of money on a bunch of unsuccessful attempts.
For the mandrel, I'm planning on using a 48" section of 2.65" Blue Tube coupler wrapped in 5 mil mylar as shown in the Jim Jarvis guide to composite rockets. My main concern is the tube spirals. I'm thinking about applying compression, and I'm not sure if the pressure could cause the mylar to bulge down into the spiral grooves. I'll probably fill them just to be on the safe side.
For the actual materials, I'm planning on using the Soller Composites 3k 2x2 Twill, mostly because it's cheap enough that I can afford to screw up some tubes. I think that I can get away with just two layers as this will be a midpower sport flying rocket. I'm not quite sure what Aeropoxy laminating epoxy to use though. Jim recommends using the 3665 hardener with the 3032 resin, but he says that it requires an oven to set up. The data sheet says that it sets up at room temperature, so I don't know if it has been changed at all since the guide was written. I don't have an oven, and I don't want to have a tube that won't set up on my hands. I live in Southern California, so the weather should be warm enough to get it to set up.
My final quandry is how to get a good surface finish. Peel ply is the obvious answer, and I'll probably use that for the fin can, but it looks like it will take a lot of work to get a really good finish with it. I've seen some people on here get good results with mylar film and with the Soller Composites heat shrink tubing, and I'd like to use those if possible.
For the mandrel, I'm planning on using a 48" section of 2.65" Blue Tube coupler wrapped in 5 mil mylar as shown in the Jim Jarvis guide to composite rockets. My main concern is the tube spirals. I'm thinking about applying compression, and I'm not sure if the pressure could cause the mylar to bulge down into the spiral grooves. I'll probably fill them just to be on the safe side.
For the actual materials, I'm planning on using the Soller Composites 3k 2x2 Twill, mostly because it's cheap enough that I can afford to screw up some tubes. I think that I can get away with just two layers as this will be a midpower sport flying rocket. I'm not quite sure what Aeropoxy laminating epoxy to use though. Jim recommends using the 3665 hardener with the 3032 resin, but he says that it requires an oven to set up. The data sheet says that it sets up at room temperature, so I don't know if it has been changed at all since the guide was written. I don't have an oven, and I don't want to have a tube that won't set up on my hands. I live in Southern California, so the weather should be warm enough to get it to set up.
My final quandry is how to get a good surface finish. Peel ply is the obvious answer, and I'll probably use that for the fin can, but it looks like it will take a lot of work to get a really good finish with it. I've seen some people on here get good results with mylar film and with the Soller Composites heat shrink tubing, and I'd like to use those if possible.