Extending E Match wires?

Running into a problem where I need longer e match wires than the standard length. Ordering new ones isn't an option right now. Can I cut lead lengths from other e matches and solder them to extend and heat shrink them? Anyone done this? Any info?

Done it and it works great. Stagger the joint and apply heat shrink tubing over the solder joint. Twist the leads if needed.......

I use old CAT5 cable. Solid core. Comes in twisted pairs. I just twist and tape the joint.

pondman said:

Done it and it works great. Stagger the joint and apply heat shrink tubing over the solder joint. Twist the leads if needed.......

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As pondman says, this does works great - stagger the ends and use heat shrink. Sometimes I just twist about a 1" section if I don't have time to solder. But always use heat shrink over the joint.


Tony

As already stated it works fine, I had some E-Matches with a 7' lead but ran out of those so I had to attach an extension when doing Air-Starts etc.

Rob702Martinez said:

Running into a problem where I need longer e match wires than the standard length. Ordering new ones isn't an option right now. Can I cut lead lengths from other e matches and solder them to extend and heat shrink them? Anyone done this? Any info?

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I just did this on a recent flight, but I consider soldering to be home on the bench. Is there any other solution? I can see where twisting without solder and covering with heat shrink could work, but I would like to find out if there are any other solutions.

manixFan said:

As pondman says, this does works great - stagger the ends and use heat shrink. Sometimes I just twist about a 1" section if I don't have time to solder. But always use heat shrink over the joint.


Tony

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I do it all the time, I just don't solder them. IMO that is a waste of effort. A solid mechanical joint and a bit of electrical tape is all you need for this to work. If you offset the joints by a few inches, the tape is not even necessary.

Based on recent experiments with the wire-wrap method common in the (guessing) 50-80's, I speculate that using some safety wire pliers to do an extension vs solder would be ok for ground started motors. I'd be very concerned about that option on air starts without more study for sure.

Safety-wire pliers are cool too, so if you don't have a good pair, maybe hunt on ebay, as I think the old school versions are available and probably better than something that is low cost produced in recent years. With my pair, you feel a flex in the handle that was there by design, not by accident and I'm sure they were used for years building aircraft before I got them.

Again, my suggestion is just a guess and not an accepted method by any form of code or electrical engineer. I speculate it could be a quick and easy way for field work and ground starts only.

Notes about pics: 1st is the twist with the pliers, 2nd is the resistance of the joint, 3rd is the resistance of the meter leads. Additionally note that using a DMM (even a good one) to measure super low resistances is a bad practice. Usually extremely low resistances are less than the meter shows, so assuming 0.15 ohm in the leads and 0.16 ohm on the joint means that it is likely less than 0.01 ohm, which isn't half bad for joint in such small wire. Not real science, but kinda correct in my mind. . .

Sandy.

Just cut off a piece from a used ematch and strip/twist/tape the ends. I do it all the time, especially with AT 29mm igniters... which are way too short for most HPR pads. H_Rocket is right about offsetting the twists, but I tape them anyway so they won't short on the pad itself (vs each other).

I do it all the time, I never bother with heat shrink or solder. Just stagger, twist tightly, and wrap with tape.

these are wire connectors made specifically for igniters

https://electricmatch.com/rocketry/see/38/6/duplex-wire-connector

I carry a battery powered soldering iron, but for what you’re doing I would just splice the wire using the splicing method described here:
https://armymunitions.tpub.com/MM01...Using-The-Western-Union-Pigtail-Splice-21.htm