3D printed retention?

Discussion in 'Mid Power Rocketry (MPR)' started by Sparrowhawk, Jul 14, 2019.

Help Support The Rocketry Forum by donating:

  1. Jul 14, 2019 #1

    Sparrowhawk

    Sparrowhawk

    Sparrowhawk

    Active Member

    Joined:
    Aug 27, 2018
    Messages:
    26
    Likes Received:
    1
    Gender:
    Male
    I'm designing a rocket with a 41.6mm (BT-60) body tube and a 29mm motor mount; I couldn't find any (cheap!) engine retention solutions for composite engines at these dimensions, as all the (cheap!) retainers I could find had an OD larger than 41.6mm. I found a great model on thingiverse (https://www.thingiverse.com/thing:3691731/files), and I was wondering if it's feasible to do something like this in PLA filament. Will it melt?
     
  2. Jul 14, 2019 #2

    cwbullet

    cwbullet

    cwbullet

    Obsessed with Rocketry Staff Member Administrator TRF Lifetime Supporter Global Mod

    Joined:
    Jan 24, 2009
    Messages:
    22,381
    Likes Received:
    1,330
    Gender:
    Male
    Location:
    Glennville, GA
    PLA is too flexible in the summer heat - go with petg.
     
  3. Jul 14, 2019 #3

    Sparrowhawk

    Sparrowhawk

    Sparrowhawk

    Active Member

    Joined:
    Aug 27, 2018
    Messages:
    26
    Likes Received:
    1
    Gender:
    Male
    I suppose I do need some new filament anyway... I’ll buy some PETG then.

    Will it melt from the heat of the engine casing?
     
  4. Jul 14, 2019 #4

    cwbullet

    cwbullet

    cwbullet

    Obsessed with Rocketry Staff Member Administrator TRF Lifetime Supporter Global Mod

    Joined:
    Jan 24, 2009
    Messages:
    22,381
    Likes Received:
    1,330
    Gender:
    Male
    Location:
    Glennville, GA
    It will melt but I have not had it melt from the motor casing.
     
  5. Jul 14, 2019 #5

    Sparrowhawk

    Sparrowhawk

    Sparrowhawk

    Active Member

    Joined:
    Aug 27, 2018
    Messages:
    26
    Likes Received:
    1
    Gender:
    Male
    Sorry that is confusing me a little. Are you suggesting that it will melt or won’t melt during a launch
     
  6. Jul 14, 2019 #6

    cwbullet

    cwbullet

    cwbullet

    Obsessed with Rocketry Staff Member Administrator TRF Lifetime Supporter Global Mod

    Joined:
    Jan 24, 2009
    Messages:
    22,381
    Likes Received:
    1,330
    Gender:
    Male
    Location:
    Glennville, GA
    The retainer should be mounted to a paper tube. It will retain the motor. I've never had one melt except around the end with the motor throat.
     
  7. Jul 14, 2019 #7

    Sparrowhawk

    Sparrowhawk

    Sparrowhawk

    Active Member

    Joined:
    Aug 27, 2018
    Messages:
    26
    Likes Received:
    1
    Gender:
    Male
    Oh when I said motor casing I just meant the heat from it going thru the mmt lol sorry if that was worded badly. So structurally it will still hold?
     
    Last edited: Jul 14, 2019
  8. Jul 14, 2019 #8

    cwbullet

    cwbullet

    cwbullet

    Obsessed with Rocketry Staff Member Administrator TRF Lifetime Supporter Global Mod

    Joined:
    Jan 24, 2009
    Messages:
    22,381
    Likes Received:
    1,330
    Gender:
    Male
    Location:
    Glennville, GA
    Yes. It will hold. I print with 100%i infill
     
  9. Jul 14, 2019 #9

    Sparrowhawk

    Sparrowhawk

    Sparrowhawk

    Active Member

    Joined:
    Aug 27, 2018
    Messages:
    26
    Likes Received:
    1
    Gender:
    Male
    cool, thanks!
     
  10. Jul 16, 2019 #10

    swatkat

    swatkat

    swatkat

    Well-Known Member

    Joined:
    Jun 25, 2014
    Messages:
    1,330
    Likes Received:
    117
    Print solid. PETG, or PLA Pro. I've not had one fail, up through level 2 motors. One kit has Nine 38mm H and I motor launches and the outer retainer is just a bit discolored. You can always print a new outer retainer...
     

Share This Page