Level 3 Build Thread

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Finally I had a little time to get some work done. I used some Proline 4500 to epoxy the stainless 1/4X20 nuts into the back plates. To control the epoxy I cutoff a q-tip and used it for precise application to avoid getting epoxy in the threads of the nuts.

Learning: Not all rail buttons are designed the same. RailButtons.com have a #10 machine screw hole. Binder Design makes their 1515 rail buttons with a 1/4” in. hole. I went with Binder due to my back plate design for 1/4” in. nut.
 

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Experimented with the motor tube and centering rings to make sure I would be able to get it past the rail button mount. Lots of clearance by angling past the rail button mount. Looks like I have a good bond and I’m waiting for the epoxy to cure. (Note: Yes an oil was applied to all hardware to prevent accidental bonding of the wrong parts.)
 

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Real rocketry went on tonight! I had to use some hobby files and the Dremel to shape things for a final test fit. Before motor tube installation I will need to measure the estimated volume needed for each fin dam then the motor tube will be epoxied in.

Every small step gets me closer to my fall launch goal.
 

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Last step complete before the motor installation. This was much easier than I expected and none of the epoxy dams leaked! I used a big 100 cc syringe to measure the volume of epoxy needed for the fin dams. I made sure to eliminate as many air bubbles as possible to make the most accurate measurement possible.
 

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Well look at that, just look at it. The motor tube is installed. I used my paper drip prevention method, which worked out great. One of my kids held the motor tube up so I could apply some epoxy to the aft centering ring. I also test fit all of the fins just to make sure proper fit of the fins was maintained.
 

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Last step complete before the motor installation. This was much easier than I expected and none of the epoxy dams leaked! I used a big 100 cc syringe to measure the volume of epoxy needed for the fin dams. I made sure to eliminate as many air bubbles as possible to make the most accurate measurement possible.
That's what I did for my 4" test build that I'm doing on the 5" L3. About 1.75oz per fin to fill the dams. Made a darn strong and stiff bond on the 4".

Think I'm using a #8 needle to fit in the fin slot.
 
That's what I did for my 4" test build that I'm doing on the 5" L3. About 1.75oz per fin to fill the dams. Made a darn strong and stiff bond on the 4".

Think I'm using a #8 needle to fit in the fin slot.
What epoxy are you using? I have been using Proline 4500
 
I laid down 1 pice of masking tape at a time and drew an outline of where the motor retainer goes. I then used my hobby knife to trim the excess. This one fillet took 11.6 grams of epoxy. Now I just need to fillet the top centering ring tomorrow night. Getting closer to having a fin on every day.
 

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So why the picture of a trash can? The 100cc syringe was supposed to send Proline 4500 to fillet the top centering ring. I believe the pressure from the plunger caused the Proline 4500 to thicken too much in the tube causing failure.

I quickly mixed up more Proline 4500 and poured it straight down and used a dowel with a wide popsicle stick taped to it to make the fillet. The paper hat was used to protect the motor tube and Kevlar harness.

Fillets done and time to inject those fin dams once dry.
 

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So why the picture of a trash can? The 100cc syringe was supposed to send Proline 4500 to fillet the top centering ring. I believe the pressure from the plunger caused the Proline 4500 to thicken too much in the tube causing failure.

I quickly mixed up more Proline 4500 and poured it straight down and used a dowel with a wide popsicle stick taped to it to make the fillet. The paper hat was used to protect the motor tube and Kevlar harness.

Fillets done and time to inject those fin dams once dry.
Ok...

how long is your booster tube and how the heck did you pour it down there without getting it all over the sides? Curious because I do need to tweak my upper centering ring/booster filet, but my tube is 60".
 
Ok...

how long is your booster tube and how the heck did you pour it down there without getting it all over the sides? Curious because I do need to tweak my upper centering ring/booster filet, but my tube is 60".
The booster is 60" and my measurements come from the actual top of the centering ring; it's an Ultimate Wildman kit.
  1. Prepare EVERYTHING prior to mixing the epoxy!
  2. I measured from top centering ring (41" in.) to top of the motor tube (38" in.) this means the motor protrudes out 3"in.
  3. Taped 2 sheets of printer paper together and cut a 2 1/2" in. stip then formed a paper tube using a 4" in. body tube as a guide and made it almost 5"in diameter to cover the epoxied kevlar harness.
    1. Note: I made it 2 1/2" in. to give me a gap at the bottom where I do want epoxy.
  4. Used a hot glue gun to attach my tube to a flat piece of paper thus making a cap for the motor tube.
    1. Note: I used a yard stick with making tape to install the motor tube protection cap.
  5. To control the epoxy from going all over the body tube I joined 4 sheets of printer paper with tape and then used a heat gun and a body tube to make the curve. Tapped in place and poured on the protected side.
  6. Spread the epoxy by using a popsicle stick taped to a dowl rod to make that fillet. Use a popsicle that will work best for body tube and motor mount fitment.
  7. Clean up:
    1. Carefully remove the paper shield
    2. Use a yardstick with double sided masking tape (just roll a piece of masking into a loop sticky side out) to remove the motor tube protection cap
    3. Last is a blue shop towel with isopropyl alcohol to reach any small drips and then tape a blue shop towel to a yardstick with isopropyl alcohol to reach spots your hand can't.
 
The booster is 60" and my measurements come from the actual top of the centering ring; it's an Ultimate Wildman kit.
  1. Prepare EVERYTHING prior to mixing the epoxy!
  2. I measured from top centering ring (41" in.) to top of the motor tube (38" in.) this means the motor protrudes out 3"in.
  3. Taped 2 sheets of printer paper together and cut a 2 1/2" in. stip then formed a paper tube using a 4" in. body tube as a guide and made it almost 5"in diameter to cover the epoxied kevlar harness.
    1. Note: I made it 2 1/2" in. to give me a gap at the bottom where I do want epoxy.
  4. Used a hot glue gun to attach my tube to a flat piece of paper thus making a cap for the motor tube.
    1. Note: I used a yard stick with making tape to install the motor tube protection cap.
  5. To control the epoxy from going all over the body tube I joined 4 sheets of printer paper with tape and then used a heat gun and a body tube to make the curve. Tapped in place and poured on the protected side.
  6. Spread the epoxy by using a popsicle stick taped to a dowl rod to make that fillet. Use a popsicle that will work best for body tube and motor mount fitment.
  7. Clean up:
    1. Carefully remove the paper shield
    2. Use a yardstick with double sided masking tape (just roll a piece of masking into a loop sticky side out) to remove the motor tube protection cap
    3. Last is a blue shop towel with isopropyl alcohol to reach any small drips and then tape a blue shop towel to a yardstick with isopropyl alcohol to reach spots your hand can't.

ok, thats how I thought to do it. this was for my 4" rocket, building too many at same time I forget which one has what issues. :)

For my l3 I'm building out the 5" Drago XL. To make sure I got a good filet on it when I mounted the motor mount, I really lathered the inside of the tube with epoxy but definitely got to make sure you have a nice consistent thickness around the entire tube.
 
I had a Star Wars moment tonight with setting up to sink the first fin in Epoxy. The bright green light is a construction laser on my plumb bob string. I would have put in a fin tonight but I’m waiting for Amazon to deliver some T-88 epoxy.
 

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Thank you to my TAP for the best size syringe to use for injecting the epoxy dams. Amazon delivered some T-88 epoxy today and fin number 1 is mounted. I used my standard plumb line and also used a laser level for fun. Everything is nice and straight; just waiting for the epoxy to dry.
 

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I use the heated bed in on my 3D printer to warm the epoxy to 33C (91f) because my basement / rocket lab is 68f or cooler. So fin number 2 is curing in a bath of T-88 epoxy and tomorrow I should have all 3 fins on. 🤞
 

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Trued / ensured a flat cut on both sides of the nose cone coupler and mounted a U-bolt for the recovery system. I also started fin fillet prep. I’m trying to have a finished booster section by the end of this weekend.
 

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