Does anyone know where I can buy a low-priced 38mm engine retainer? If someone is willing to 3D print one for me, we can discuss terms.
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Wanted Low price 38mm engine retainer
- Thread starter Joekeyo
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Launch Lab Rocketry makes a molded plastic one. They have in Blue or Gray. Here is the Gray one.
https://www.launchlabrocketry.com/shop/p/38mmplasticmotorretainergray?rq=Retainer
https://www.launchlabrocketry.com/shop/p/38mmplasticmotorretainergray?rq=Retainer
You just missed discounts from Launch Lab Rocketry. Their 38mm hard plastic retainer is normally $17, I think.
3D printed would be cheaper, but I haven't found a nice screw type 38mm one. You could scale one of the many 29mm STLs, but that would require some experimentation to get right.
3D printed would be cheaper, but I haven't found a nice screw type 38mm one. You could scale one of the many 29mm STLs, but that would require some experimentation to get right.
The cheapest retainer is tape.
What diameter rocket? If large enough to fit, these are the same as the Z clips provided with many high power kits. I ditch the wood screw and install a t nut....which is a couple bucks for a 25 pack at the local hardware store.
https://a.co/2GZg2aC
https://a.co/2GZg2aC
jimzcatz
Boss, Carolina Rocket Mafia
This is the correct answer. Its called friction fit,comes stock on your Este's Mosquito. We have been using this method since the civil war!!
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I even friction fit an N motor this year!
I did such a good job @tjsnakez had to use a come-along to get the case out of the rocket.
Braden
Tape is your best friend
Second best and cheapest is the Launch Lab retainer. I have a few of these and they are REALLY nice. The 38mm one is a bit bulky but that's not a bad thing. I really like them, they are very high quality injection molded parts, and their price point is fantastic. I plan to use them on new builds where I don't need the extreme robustness of an Aeropack.
Second best and cheapest is the Launch Lab retainer. I have a few of these and they are REALLY nice. The 38mm one is a bit bulky but that's not a bad thing. I really like them, they are very high quality injection molded parts, and their price point is fantastic. I plan to use them on new builds where I don't need the extreme robustness of an Aeropack.
Has anyone mentioned to you the old Z clips from old timey rocketry days? Just a couple if bucks at the hardware store and two screws.
Missed that, sorry and thanks! Multitasking (working lol).
No worries. There are also similar mirror clips that can be found at hardware stores more readily (at least in my experience) and those seem to work just fine and may fit smaller body tubes than these table top fastener clips.
bibbster
Well-Known Member
I use the Launch Lab retainer for the same reason you are asking. Best bang for your buck. Aluminum retainers are pretty, but I can't justify the cost.
Tape works. Some folks like it and some don't. For me, it looks like a last minute 'fix' and it has to be removed and added every flight. Just not my thing.
Tape works. Some folks like it and some don't. For me, it looks like a last minute 'fix' and it has to be removed and added every flight. Just not my thing.
I you are going to pay for a reusable trainer, buy Aeropack. I you are going cheap, use tape.
bibbster
Well-Known Member
Why Aeropack over Launch Labs?
It is aluminum. It is more durable. I like the PC Launchlabs, but it is not as durable in my book.
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Those work too, but you can get two rolls of tape for that.
ThirstyBarbarian
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I bought a couple of the launch lab plastic retainers. They remind me of the Estes plastic screw-on retainers, just bigger for 38mm. I think they will work well, and I know a few people who use them and are happy with them. These were to replace some z-clips that came with some LOC kits.
Unless you roll your own from scrap!
A pair of needle nose pliers will easily transform one of these here things (scarfed from a hanging file folder at work) into these here retention clips, gratis.
The top one is for a 54-38 adapter, thus the double step.
Use what you have.
I think I'd pick tape over z-clips all day. But I prefer quicker change retainers like Aeropacks or Slimlines.
ThirstyBarbarian
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If anyone wants the z-clips I replaced with Launch Lab retainers on my two LOC rockets, I can save you 47 cents with my low, low offer of 6 bucks each! Supplies are limited! Don’t miss out!
beeblebrox
8 C6-0, 12 D11-9, 20 D20-0, 20 E5-0, 3 Cinerocs
3/4" Masking tape thrust ring for non reloadables. Two wraps of tape around the joint at end of motor mount tube to prevent motor eject. Tried and true for half a century and counting... Z-clips are good, but not for minimum diameter...
Heck, on Amazon, you can get enough masking tape for a lifetime of flights for less than $20.
Thanks everyone for your suggestions. I was really looking for screw on retainers only. I am a big fan of friction fit (tape). I got my level 1 using it. I just like the aesthetic and reliability (?) of the screw cap retainers. I am aware of the Launch Lab product. I think it is over priced. The price is almost right, if it included shipping. Just how I feel about it. I know they have to make a living and all.
Keep asking. Someone can print one for you. We see a lot of college students with 3D printed screw on retainers. Someone can give you the file and someone else can print it for you.
bibbster
Well-Known Member
You gotta buy more stuff and get free shipping! 
With some testing, I could print one for you for a few bucks.
LithosphereRocketry
Pining for the Fjords
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If you want something more positive than tape for cheap, I like using a piece of allthread rod epoxied to the motor mount with a nut threaded on it that sits against the edge of the motor. If you're feeling fancy, use two nuts jammed against each other to prevent slipping - I wouldn't recommend locknuts as the nylon insert tends to get toasted by motor splashback.
