Terminal blocks vs twist-and-tape for ematches

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Not Quite Nominal

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I've used twist-and-tape for altimeter switching, second stage igniters, etc, with zero failure. I've had terminal blocks pull off the bulkhead, wires come loose, etc. on terminal blocks. I'm starting to think that terminal blocks have a whole lot of tiny, fiddly failure points.

Any reason why twist-and-tape isn't a more popular method of attaching ematches?
 

Titan II

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I am also a TnT person. It seems a lot of people think making AV bays with lots of parts/gadgets make it look cooler, or more professional, or it makes them feel more like a rocket scientist.
 

cerving

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I rarely use terminal blocks anymore, most of my builds have pigtails soldered to the altimeters, and exiting out of the AV bays. I plug the hole with putty, and twist-and-tape the ematches. I'm still looking for some kind of easily removable rubber plug for the holes.
 

jmuck78

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Any reason why twist-and-tape isn't a more popular method of attaching ematches?
I can tell you why I use terminal blocks - although I am considering twist-and-tape for some future builds. I like the reusability of the terminal blocks and the fact that they are secured away from the harness. I have tried twist and tape for temporary connections and have a hard time keeping the connections from breaking just under bench conditions. I'm obviously doing it wrong, but that means I have more confidence in the terminal block connections. I'd be happy to have some suggestions on how to twist and tape in securely, to be quite honest.
 

Steve Shannon

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In 23 years around technicians I never ever heard one extoll the virtues of twisted connections rather than terminal blocks. Personally I avoid any extra connection points when possible, but I’ve never had a problem with a terminal block. There are some things to avoid though. Read the data sheets for any electrical components to see what they are.
 

Not Quite Nominal

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I rarely use terminal blocks anymore, most of my builds have pigtails soldered to the altimeters, and exiting out of the AV bays. I plug the hole with putty, and twist-and-tape the ematches.
That's what I've been considering (minus the soldering). It saves on bulkhead space, and I used it for an LPR DD rocket for that reason. I plugged the hole with epoxy though, which committed me to building a new bulkhead if the wires got damaged.

Putty solves that problem.

Have you ever had the wires fouled by recovery components shifting, or catching on something?

I can tell you why I use terminal blocks - although I am considering twist-and-tape for some future builds. I like the reusability of the terminal blocks and the fact that they are secured away from the harness
Secured away from the harness seems to be a good feature, especially if you're also using charge wells. Since I tend to use centrifuge canisters, I already have some loose wire hanging around. Charge wells and terminal blocks do start eating up quite a bit of bulkhead real estate though.
 

Buckeye

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I'd be happy to have some suggestions on how to twist and tape in securely, to be quite honest.
Me, too. My electrical tape jobs are a mess and often come loose in both hot and cold weather.
 

Buckeye

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Another risk with terminal blocks is cutting the wires. This is especially true for those that use a set screw to clamp the wire. The set screw may be very small in diameter or have sharp edges that can cut ematch wires. Cheap, Chinese "European Terminal Blocks" sold on Amazon are more prone to this than quality blocks sold by Mouser, etc. Better yet are the terminal blocks like those on altimeters that have a large surface area to clamp the wires.
 

FredA

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Another risk with terminal blocks is cutting the wires. This is especially true for those that use a set screw to clamp the wire. The set screw may be very small in diameter or have sharp edges that can cut ematch wires. Cheap, Chinese "European Terminal Blocks" sold on Amazon are more prone to this than quality blocks sold by Mouser, etc. Better yet are the terminal blocks like those on altimeters that have a large surface area to clamp the wires.
My ONLY airstart failure out of probably something close to 100 has been due to this - the wire was broken by the screw on the terminal block. Since it was on an airstart channel I had disabled continuity checking for a precaution.

Once burned, I now know to check for this and will continue to use terminal blocks on Ebay's with enough bulkhead space.

Having term blocks for ematches allows me to turn around the Ebay quickly if I'm not unloading the data which is usually the case.
And no, I don't change the battery but once a season unless it ran a long time due to an extended recovery time.
 

Bat-mite

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I don't want wires sticking out of my sampling ports. Plus, I have bad fingers, and twisting wire out at the pad is not my idea of fun. I come to the launch with everything ready to go except turning on my tracker and inserting shear pins.
 

Antares JS

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I use terminal blocks, but I see nothing wrong with twist and tape; it's just a matter of personal preference. I suppose it's true twist-and-tape doesn't look as nice in pictures, but I don't see many people caring about that.
 

Buckeye

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I don't want wires sticking out of my sampling ports. Plus, I have bad fingers, and twisting wire out at the pad is not my idea of fun. I come to the launch with everything ready to go except turning on my tracker and inserting shear pins.
No, we are talking about TNT vs. terminal blocks for ematch leads on the bulkheads, not TNT as an altimeter switch.
 

jimzcatz

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Everyone will have their own opinion on this matter. My choice is Gorilla tape, not electrical tape on both ematch connections and altimeter switching. I have never used terminal blocks nor switches.
 

David Schwantz

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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.
 

rdrown

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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.
The above plugs will not ship to the USA
 

Grog6

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Look up Fahrenstock clips; I use those as they're easier to attach remove, and never fail s connection.
I use gold plated ones for igniters.https://external-content.duckduckgo.com/iu/?u=http%3A%2F%2Fi.ebayimg.com%2F22%2F!BdSw0ogCGk~%24(KGrHqMH-EUErfFbc%2BuvBK4OzBJ!Yw~~_35.JPG&f=1&nofb=1
 

David Schwantz

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Because Cris asked what kind of plugs could be used. There are many different kinds, types, shapes. These were the best looking I could find. Sorry you were so offended by my trying to help someone.
 

MoreCowbell

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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.
 

Art Upton

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I seal the hole with "tub and tile" caulk. Peals back off easy.
 

David Schwantz

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I will have to look. Thanks Greg. By the way, were going to make it to a launch. Sept is just a couple weeks out. I have been looking for another M2050X for the V 2, but all out of stock.
 

Greg Furtman

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I will have to look. Thanks Greg. By the way, were going to make it to a launch. Sept is just a couple weeks out. I have been looking for another M2050X for the V 2, but all out of stock.
Hi David, I'm having a hip replacement next week so I'll be laid up for awhile. This getting old crap! :(
 
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