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  1. #1
    Join Date
    18th January 2016
    Location
    St. Louis
    Posts
    848

    Jolly Logic Chute Release & EPDM Rubber Bands

    I'm on my 4th latex rubber band with my Chute Release. They tend to break over time after storage; as natural latex tends to do. I have a bag of EPDM rubber bands that I'm thinking of using. They don't wear out over time like latex does. Also, EPDM rubber is a little bit more heat resistant than latex (300 F vs 220 F) according to this sheet I found:

    https://www.professionalplastics.com...rsOverview.pdf

    Has anyone else tried using something other than the latex bands included?

    My last launch, the bands broke when I was bundling the chute, and I didn't have any other spares with me. It makes me paranoid that some time, they will break when the chute deploys on flight.

    FYI, a big ole' bag of 100+ EPDM rubber bands is only about $7 or so. Mine are too long, so I'll have to double over the bands.

    Mark
    NAR#: 100890 / TRA#: 16580
    L1 - Binder Design Excel Plus 38 - CTI I242 2,540'
    L2 - Binder Design Excel Plus 38 - CTI J330 3,672'
    L3 - Scratch built 8" PAC-3 MSE Patriot - Loki M1969 (ETA MWP 15)

  2. #2
    Join Date
    21st September 2017
    Location
    NY/NJ
    Posts
    67
    How long (months, flights) do they last you on average?

    I'm on my first band after ~6 months and ~15 flights so far....

    a


  3. #3
    Join Date
    18th January 2009
    Location
    Maryland
    Posts
    11,456
    My first band lasted a year and a half and on maybe 15 flights too (just a guess). It broke when I tried to wrap it around a 60" chute. I think any type bad will generically work but you will have to ground test to see what size chutes they will work with.
    Dick Stafford
    The member formerly known as the Pointy-Haired Moderator.
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  4. #4
    Join Date
    18th January 2016
    Location
    St. Louis
    Posts
    848
    Quote Originally Posted by afadeev View Post
    How long (months, flights) do they last you on average?

    I'm on my first band after ~6 months and ~15 flights so far....

    a
    I drop the CR into several models. I've been using it for a little over a year, I believe. Can't recall when I bought it. Not a clue on flight count. Maybe....6 flights per band? The BP charges on my smaller models is overpowered from the stock motors, so it's a bit harsher. I stuff a bunch of dog barf into the frame to help guard it.
    Mark
    NAR#: 100890 / TRA#: 16580
    L1 - Binder Design Excel Plus 38 - CTI I242 2,540'
    L2 - Binder Design Excel Plus 38 - CTI J330 3,672'
    L3 - Scratch built 8" PAC-3 MSE Patriot - Loki M1969 (ETA MWP 15)

  5. #5
    Join Date
    15th October 2016
    Location
    Huntsville AL
    Posts
    1,474
    A fellow club flyer used this weird band that looked like a bungie/hairband hybrid.

    I borrowed his chute release before getting my new one. Unfortunately, the band felt a bit slick and totally slipped the chute at apogee (only 1/4 mile up, could have been worse!). He told me I probably hadn't made it tight enough, but then it did the exact same thing to him lol.

    Whatever you try, make sure its grippy enough when tight, but doesn't grab the chute upon release.
    "I'm at least 70% confident about whatever I say (90% of the time)"- college me

    NAR 101195
    Level 1: Big SAM, 9/10/16

  6. #6
    Join Date
    15th October 2015
    Location
    Minnesota
    Posts
    1,217
    My first factory-supplied band broke after only a couple flights and a few months storage at room temp. It even left behind chunks stuck to the ring that had to be peeled off. After that, I decided to add that to the launch checklist as well as to just use a new one if the flight is expensive.
    NASA success rate since 2000: 94.7%
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  7. #7
    Join Date
    18th January 2009
    Location
    Maryland
    Posts
    11,456
    Quote Originally Posted by Cabernut View Post
    My first factory-supplied band broke after only a couple flights and a few months storage at room temp. It even left behind chunks stuck to the ring that had to be peeled off. After that, I decided to add that to the launch checklist as well as to just use a new one if the flight is expensive.
    Latex will be sensitive to both heat and sunlight so people's launch environments will have varying impacts. Also, as much as possible, I always make sure mine is in a box when not in a rocket. After my first one broke, I always inspect and overstretch it before use. If on a new chute/application, I do the shake and release tests.
    Dick Stafford
    The member formerly known as the Pointy-Haired Moderator.
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  8. #8
    Join Date
    26th October 2009
    Location
    Sheboygan WI
    Posts
    1,204
    I had a fresh out of the box band break while attaching it to the unit. I did not over stretch it or do anything that should have caused the break. They are kept in the room with my motors etc. I guess the bands can have defects whatever. Did inspect and stretch the second one, works fine.
    _______________________
    Jeff - NAR #76531 -L2

  9. #9
    Join Date
    10th July 2007
    Location
    Melbourne, Australia
    Posts
    1,036
    What about just buying a bag of them and using a new one each launch? Easy decision for me if I were using them.
    TRA 13430, Level 3

    "Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

  10. #10
    Join Date
    21st September 2017
    Location
    NY/NJ
    Posts
    67
    Quote Originally Posted by OverTheTop View Post
    What about just buying a bag of them and using a new one each launch? Easy decision for me if I were using them.
    They aren't THAT cheap ($13 for a bag of 15), and why waste money if the old ones are still good?
    It's fairly easy to inspect them during attachment, and determine if they rubber is cracking or not.

    I've been flying mine in all the rockets big enough to fit the CR (low, mid, and HP). Still yet to break the first band.
    Not to say it will last forever, but I inspect it each time I strap it around the chute, then test it more when shaking the chute to make sure it's held tight. Not hard.

    I was curious to learn that others are using alternative bands and materials, with a seemingly highly frequency of trouble with alternative bands.
    I would love to learn what motivated them to switch, and which alternative band materials they selected, and why.

    a

  11. #11
    Join Date
    2nd October 2011
    Location
    South Dakota
    Posts
    259
    Bands like these........... for like $5.00 for a ten pack of assorted.
    Glasspack

    "Don't forget the motor casing"
    NAR 93397 - HPR Cert: LVL 1

  12. #12
    Join Date
    18th January 2016
    Location
    St. Louis
    Posts
    848
    Well I have a box of 100 EPDM bands that I'll test out. They're a bit long, so I have to double them up for small chutes.
    Mark
    NAR#: 100890 / TRA#: 16580
    L1 - Binder Design Excel Plus 38 - CTI I242 2,540'
    L2 - Binder Design Excel Plus 38 - CTI J330 3,672'
    L3 - Scratch built 8" PAC-3 MSE Patriot - Loki M1969 (ETA MWP 15)

  13. #13
    Join Date
    7th August 2013
    Posts
    301
    Silicone cooking bands, stole a couple from my mom, excellent!!!
    John Haught L3
    VP Tripoli Pittsburgh

  14. #14
    Join Date
    15th February 2009
    Location
    North Texas
    Posts
    495
    Weigh the expense of the rubber band vs. the expense of losing a rocket and the CR because the main deployed at top and it drifts out of sight and gets lost. Seems like a pretty easy decision.

    But then I'm one of those guys that uses a new 9 volt battery in my altimeters for every flight. I would much rather pay a little up front than a lot later.


    Tony
    why do people put so much stuff in their sigs?

  15. #15
    Join Date
    27th January 2015
    Location
    Rochester, NY
    Posts
    1,972
    I've used up all of the small bands that came with mine, some of which failed pretty quickly. I think they also get nicked by the split ring that attaches the pin. I've been looking for suitable replacements that are the correct size; they would seem to be #61 bands, though that isn't a common size. But a 1lb box of them is available on Amazon.
    Rick
    URRG, MARS
    Tripoli #15706
    http://www.rocketreviews.com/rick-barness-page.html

    There is a theory that states that if anyone figures out why the universe is for or why it is here, it will suddenly disappear and be replaced by something even more bizarrely inexplicable.
    There is another theory that says this may have already happened...



  16. #16
    Join Date
    5th June 2010
    Location
    Danville, CA
    Posts
    708
    You can use whichever bands or other elastic you'd like with Chute Release, as long as:

    1. They are stretchy, and stretch or break before the mechanism binds or the pin snaps
    2. They hold the chute firmly (do a shake test)
    3. They release from the chute well

    The smaller bands are #61 (2" x 0.25").
    The larger bands under the tray are #74 (3.5" x 0.375").

    In another post, someone used fabric elastic in a 38mm rocket so that it didn't "catch" on the fuselage (tight fit). And it was tight enough that it worked in that case.

  17. #17
    Join Date
    30th January 2016
    Location
    US > OK > NE
    Posts
    3,112
    Hrmm, sport headbands ( 1 side rubberized, other cloth ). I'll try and remember next time I'm at the sporting goods store.


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