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- Jan 30, 2021
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How structurally sound is that? No exterior reinforcement necessary even if considering using 54mm L motors in the future? Next flight was going to be a small K.Got a great place for a joint. Just cut the tube around the middle CR and use that as the glue joint for either a chunk of new tube or the old one squared off. Will just be 4" shorter than before. If you use new tube add a chunk of joiner above the upper CR to slide the old tube over and then glue. A little bondo and paint, you could even add a new color stripe as that will kind of hide the 2 new joints.
Like this? I really only lose 2” this way.Got a great place for a joint. Just cut the tube around the middle CR and use that as the glue joint for either a chunk of new tube or the old one squared off. Will just be 4" shorter than before. If you use new tube add a chunk of joiner above the upper CR to slide the old tube over and then glue. A little bondo and paint, you could even add a new color stripe as that will kind of hide the 2 new joints.
But the coupler tube is the same outside diameter as the CR's. I'd have to sand down the forward CR then grind a step in the lower one with a Dremmel, wouldn't I? That's why in my sketch the coupler is butted up to the forward CR.In all honesty, if you just lay epoxy on the inside of the couple after you slide it over the upper CR, and epoxy on the inside at the top, it will form nice fillets as the glue settles. I would not use foam.
Piece of cake.Or should I just build a new booster? This thing looks pretty effed to me. Worse than i first thought.
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I didn't sand and clean the surface sufficiently. Simple as that.Absolutely repairable.
If need be, just observe for a while and go through the rebuild process in your mind until you see it clearly and are happy with how to move forward.
As someone previously mentioned, it is concerning that the epoxy broke so cleanly from the airframe.
What epoxy are you using? What is your prep method? Why did it fail looking like it never really bonded, especially given that the airframe broke so easily?
Wow, you need to tell us how this thing broke where it did. This is one of the most structurally sound areas of the rocket and usually if it came down hard or motor Cato it would be damaged above the top CR joint….very weird. Please tell what type of launch fatality this rocket experienced.Or should I just build a new booster? This thing looks pretty effed to me. Worse than i first thought.
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Wow, you need to tell us how this thing broke where it did. This is one of the most structurally sound areas of the rocket and usually if it came down hard or motor Cato it would be damaged above the top CR joint….very weird. Please tell what type of launch fatality this rocket experienced.
You just described my whole life.Chain of events and errors
Sometimes I get it right and have only one error or one bad event; otherwise I like to say, "One crisis at a time, please."You just described my whole life.
Thanks for the sketch. Makes more sense now. So you don't think the coupler is a good idea? I figured it would give more bonding area and strength. Any suggestions on making the dowel spacers accurately? I don't exactly have a full shop here.The alignment that's most critical is motor. Assuming the motor mount tube has no damage, use a long dowel through the whole thing to keep the motor alignment straight. Fit a temporary centering ring inside the new tube as far away from the join. ( at the new unglued end) just needs to be a good push fit don't glue.dowel through the whole lot. Not seeing any advantage from the coupler. Just adds weight.
From the pictures it doesn't look like you had good bonding with the tube. Measure inside the tube to where your glue joints are going to be and using a bamboo skewer you can get a long way in to apply glue around the area of the joint and pre wet the cardboard tube.
Best of luck. It looks totally recoverable. See below. Your dowel and spacers to motor mount just need to be an assembled tightish fit. No need to glue the dowel in.... and obviously Ive only shown where to pre-wet not the other gluey bits...
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know anyone with a 3D printer?Thanks for the sketch. Makes more sense now. So you don't think the coupler is a good idea? I figured it would give more bonding area and strength. Any suggestions on making the dowel spacers accurately? I don't exactly have a full shop here.
Good preparation of a glue joint is CRITICAL...... There's nothing difficult about the prep. sandpaper/ solvents/ long bits of bamboo skewers( satay sticks) masking tape to stop the glue going where it's not supposed to. You can get more strength from a joint with less glue and correct preparation, than a bucket load and no preparation..... If you are weighing out glue, do it all in the one cup. Measure part1, zero the scales and measure part2 into the same zero'd cup with part 1 in it. If you have a spot of dye that wont react with it, add a drop in and mix until you see NO streaks , it's just an even colour( whatever colour that its.Thanks for the sketch. Makes more sense now. So you don't think the coupler is a good idea? I figured it would give more bonding area and strength. Any suggestions on making the dowel spacers accurately? I don't exactly have a full shop here.
What do you think of filling the void between the CR's with 2-part foam to lock the joined area to the motor tube and make everything more solid? It's about 4:2 against in my little poll. I can calculate the volume pretty closely and mix less than needed. You can also apply that stuff in multiple (small) batches, too. It's tricky stuff, but I've worked with it before. Wouldn't it make a nice, solid, well adhered segment that is fully integrated into the rest of the rocket?Good preparation of a glue joint is CRITICAL...... There's nothing difficult about the prep. sandpaper/ solvents/ long bits of bamboo skewers( satay sticks) masking tape to stop the glue going where it's not supposed to. You can get more strength from a joint with less glue and correct preparation, than a bucket load and no preparation..... If you are weighing out glue, do it all in the one cup. Measure part1, zero the scales and measure part2 into the same zero'd cup with part 1 in it. If you have a spot of dye that wont react with it, add a drop in and mix until you see NO streaks , it's just an even colour( whatever colour that its.
This avoids getting all of one of the parts out if you use 2 measuring cups then mix. There's always some left in one cup. This gives you a wrong ratio at mixing. I'll stop there as I'm running the risk of annoying the glue gods
Your Avatar doesn't state where you are. We're all going to assume (ass u me) that you have access to a good store. If you let us know where you are and post a picture of your workshop/tool box we'd have a better understanding of your options. Plus we'll know where you live and can pop round to borrow some tools......
Regards
Norm
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