Terminal blocks vs twist-and-tape for ematches

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cerving

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Cris, link for plugs.


I am still in need of a couple beepers for Quarks. if you could send an invoice, that would be great. Thanks, Dave.
Thanks, I'll look these up.
 

Dad Man Walking

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Have you ever had the wires fouled by recovery components shifting, or catching on something?
This happened to me on my first DD flight. I used a cardboard tube charge container that Wildman carries, and left it dangling a few inches in the lower section. It must have gotten fouled up with the shock cord, because after the flight we saw that the wires were yanked out of the terminals. No apogee event, but the flight was saved by the motor backup and the main event worked. Learned a lesson on that one.

Back to the topic of T&T vs. external terminals, a while back I started doing T&T for the deployment charges on one of my rockets, but then found a bunch of Scotchlok connectors in my electrical parts box and decided to give them a try. Quick and easy, no need to strip the wires. Then I'll organize and tape up all of the excess wire, and the connectors, so they can't move or flop around, and are protected from whatever chaos is going on inside the tube. It's all I use now.

 

FredA

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Don't you need to cut those Scotchlok connectors off?
 

Rocks&Rockets

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Has anyone else used these WAGO 221"lever nuts" in place of terminal blocks? Come in various sizes and they are easy and secure for connecting different guage wire. I've used RTV or another "plastic approved" glue to set on a 54mm bulkhead. I like 'em !
Screenshot_20210827-112210_Firefox.jpg
 

dvdsnyd

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This happened to me on my first DD flight. I used a cardboard tube charge container that Wildman carries, and left it dangling a few inches in the lower section. It must have gotten fouled up with the shock cord, because after the flight we saw that the wires were yanked out of the terminals. No apogee event, but the flight was saved by the motor backup and the main event worked. Learned a lesson on that one.

Back to the topic of T&T vs. external terminals, a while back I started doing T&T for the deployment charges on one of my rockets, but then found a bunch of Scotchlok connectors in my electrical parts box and decided to give them a try. Quick and easy, no need to strip the wires. Then I'll organize and tape up all of the excess wire, and the connectors, so they can't move or flop around, and are protected from whatever chaos is going on inside the tube. It's all I use now.

Do you have a picture on how you use these? Confused as to your attaching to the altimeter?
 

jmuck78

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This happened to me on my first DD flight. I used a cardboard tube charge container that Wildman carries, and left it dangling a few inches in the lower section. It must have gotten fouled up with the shock cord, because after the flight we saw that the wires were yanked out of the terminals. No apogee event, but the flight was saved by the motor backup and the main event worked. Learned a lesson on that one.

Back to the topic of T&T vs. external terminals, a while back I started doing T&T for the deployment charges on one of my rockets, but then found a bunch of Scotchlok connectors in my electrical parts box and decided to give them a try. Quick and easy, no need to strip the wires. Then I'll organize and tape up all of the excess wire, and the connectors, so they can't move or flop around, and are protected from whatever chaos is going on inside the tube. It's all I use now.

Do you have to cut wires to remove the connectors/deployment charges after each flight, or is there a way to separate the connector?
 

tsmith1315

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Do you have to cut wires to remove the connectors/deployment charges after each flight, or is there a way to separate the connector?
A Scotchlock? You can open them and pull the metal connecting "blade" off the wires with pliers. Put it back together and re-use a time or two.
 

Rocks&Rockets

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Yes, they are a little big for 2"/54mm if you use "charge wells" and other hardware to keep your e-bay together. I find them perfect for my 3" rockets.
 

Scrapmaster87

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Lift the lever, remove e-match, replace with new charge... very simple and secure .View attachment 479505
I love this, I'm using speaker terminals myself: https://www.amazon.com/gp/product/B07QR5XSJX/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I have 20 flights on 1 set, but they're starting to look pretty charred. I'm working on something right now that doesn't require stripping wire in the field, I keep my pre-prepped charges in an ammo can until I'm ready to fly.
 

Not Quite Nominal

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Lift the lever, remove e-match, replace with new charge... very simple and secure .View attachment 479505
Those look incredible, especially for use w/ centrifuge canisters. I try to fiddle with the canister as little as possible once it's filled, and this looks like the perfect solution.

What's a good source for genuine ones? Half the ones on Amazon appear to be fake.
 

RocketScott

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Anyone else use brass machine screws through the bulkhead?

I solder a ring terminal to the lead from the altimeter and leave it with the av bay if I move the altimeter to another. Brass knurled nut on the charge side to hold the ematch leads then rubber screw caps to protect them
 

Rocks&Rockets

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What's a good source for genuine ones? Half the ones on Amazon appear to be fake.
I bought a couple boxes of 50 direct from the source... but mostly use the smaller 2wire.
You'll never use wire nuts again! Samples here-
 

OverTheTop

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Please shoot me if I ever use twist-and-tape instead of terminal blocks.

I have been eyeing-off those Wago flip connectors for a while. I might buy some for a build.
 
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OverTheTop

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A Scotchlock? You can open them and pull the metal connecting "blade" off the wires with pliers. Put it back together and re-use a time or two.
I would bet your left testicle that the reuse of insulation displacement connectors is not condoned by the manufacturer. You will be doing this at your own risk.

I have seen failures over the years for these sort of insulation displacement connectors. 3M is a very reputable brand and likely quite reliable, but you must have the correct wire for the correct terminal for reliability. I have seen on one occasion a failure in a 3M IDC connection. They are better than the generic no-name terminals but I am struggling to think if I have ever thought using IDC in a rocket is a reasonable idea, even if I were to use 3M devices.
 

tsmith1315

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I would bet your left testicle that the reuse of insulation displacement connectors...
MINE? Ohhhh no, we're not placing THAT bet!

FWIW, my experience with the 3M Scotchloks and their reputation in the old world of car audio was about the same as what you describe. Very rarely used by pros, only in certain circumstances.
 

cerving

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IDC connectors are designed for one-time use. The prongs deform along with the wire to provide a tight connection... as long as there is no stress on them. They are designed for stationary use and cannot handle any vibration, flexing, pulling, or any other kind of movement. I can't imagine a worse application for them than rocketry.
 

OverTheTop

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They are designed for stationary use and cannot handle any vibration, flexing, pulling, or any other kind of movement.
Generally, but it depends. Krone have a range of industrial IDC designed for high-vibration environements, including on vehicles.
 

Grog6

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I would worry about the wego connectors with igniters; the nichrome wire is so small it can pull out of the connector easily. 20awg is about the smallest wire that works well,imho.
 

bdureau

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This is what I a experimenting with for the ematches. The screws are also doing the electrical connections between the terminal blocs
IMG_20201223_152754.jpg
IMG_20201227_182620.jpg

IMG_20201227_182603.jpg

IMG_20201227_182624.jpg
 

Rocks&Rockets

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I would worry about the wego connectors with igniters; the nichrome wire is so small it can pull out of the connector easily. 20awg is about the smallest wire that works well,imho
The smaller Wego connectors are rated to hold a 24AWG and up securely. Not ideal for a 36ga NiCr bridge wire.
 

ep29030

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At hardware stores, you can buy a blue putty that is intended for sticking posters, etc. to walls without damaging the paint. It works very well for plugging the bulkhead hole. Usually in the section where they have picture hangers, etc.

I don't like terminal blocks--I run the ematches through a hole in the bulkhead, and seal the hole by packing the blue putty around the match wire. The flat of a screwdriver blade works well for compacting the putty into the hole.
Education stores sell good quality plasti-tac for bulletin boards and altimeter bays.
 

Grog6

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The smaller Wego connectors are rated to hold a 24AWG and up securely. Not ideal for a 36ga NiCr bridge wire.
Agreed; thats why i like the fehrenstock clips; if they don't hold tight enough, they are field adjustable with a fingertip. :)
 

OverTheTop

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The smaller Wego connectors are rated to hold a 24AWG and up securely. Not ideal for a 36ga NiCr bridge wire.
Who inserts a 36AWG nichrome bridgewire directly into terminals! The insulated wire on igniters will be closer to 24 or 26AWG. I will measure some later.
 

heada

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Solder a section of shooters wire to an electronics terminal block like these.

https://www.amazon.com/dp/B01MT4LC0...abc_9440PMD6NRWHY76JJ8T7?_encoding=UTF8&psc=1

Then drill a hole just big enough for the wire through the bulkhead and connect to electronics. Epoxy the term block to the top of the bulkhead. Gives very good connection to ematch wires, cheap and small and epoxy holds it in place and gives an airtight seal. Need a #00 Phillips screw driver to tighten the ematch wire in the block.
 

Scrapmaster87

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Please forgive me for my blasphemy...

My speaker terminal solution has been kinda nice so far. I have 20 flights on my Tubetastic with the only failures related to the power wires to the altimeter. I am starting to get worried about the accumulated ground impacts on lower bulkhead and charge residue on the upper. I'm also seeing some of my backup charges not firing on another build. I've been greasing the speaker terminal contacts to help keep the junk out, but I see that I need a new solution.

My philosophy is that any delicate preparation should be done at home. Field prep should just consist basic assembly, preferably without tools. As I'm doing about 4 dual deploy flights per day. That's 8 to 10 charges I'm stripping wire for, which isn't always perfect (and the stripped insulation doesn't always make it into my trash).

Enter my discovery of the XT30 power connector and the fact that is shares the same 5mm pin spacing as common PCB screw terminals. I can now have a low profile 100% tool-less charge installation in the field. I just attach my charges to my connector terminals when I'm prepping at home (with a shorting plug of course). In the field I just have to pull off the shorting cap, do a wrap around my e-bay anchor loop, and plug the end into the bulkhead.

PXL_20210904_022049654.jpgPXL_20210904_021752937.jpgPXL_20210904_021729749.jpg

I love building and solving problems, but when it's launch day I want to spend my time flying. I don't believe in transporting my rockets with motors or charges installed: if it can relate a "projectile" situation, then it must be avoided. My charges live in an ammo can until they're ready to be used, and I only make what I plan to fly plus 1 spare set.
 
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