comfortcat

comfortcat

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For my Dynon autopilot, I need to have two wires connect to a third (Red, Yellow and Black). Two into one. The one is a 1/4 spade connector. I also need to do this for my NAV lights.

Do I use a butt splice or a heat shrink with solder? Here are my options:

sg01t4.jpg


Thoughts?

Dkb
 
Not an expert here (but I have lots of experience soldering relatively fine electonic wires).... I've done it both ways on my RV. I prefer the solder method and pay extra to the details.

1) Make sure the wires are well twisted and tight to lay the foundation for strength. The solder is not intended to make the connection physically strong, but to make the connection electrically sound.

2) Smooth the ends of the twisted strands into the joint so they are not poking out which can later protude through the insulation of the final joint and touch other wires or the airframe.

3) Heat the joint and let the joint melt the solder. Let the solder solidify on it's own ( takes a few seconds) before allowing it to move so as not to contribute to a "cold solder" joint.

4) Heatshrinking (I do double heat shrink) or otherwise insulate the finished joint.

5) Secure the finished joint from vibration on both sides of the joint. Such as tywraping it to other wires in the bundle. I sometimes apply a third tywrap over the middle of the joint to further imobilize the vibratory movement.

6) You may want to document the joint on your drawing including location and what method was used to make the joint. Particularly if there is a wire color change. This may come in handy for troubleshooting or tracing wires years down the road.

Bevan
 
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Neither! Use an environmental splice. They are much faster than soldering and are much more secure than standard type butt splices due to the shrink sleeve. The shrink sleeve of an environmental splice contains adhesive bands in the ends that provide excellent strain relief for the wires at the splice crimp, as well as environmental sealing.

Buy a used set of crimpers for these splices and keep them after you are finished. Once you have used these types of splices, you WILL Not go back to standard butt splices on anything.

http://www.newark.com/webapp/wcs/st...003&langId=-1&storeId=10194&gs=true&st=M81824
 
Something NEW! (to me)

Mike H said:
Neither! Use an environmental splice. They are much faster than soldering and are much more secure than standard type butt splices due to the shrink sleeve. The shrink sleeve of an environmental splice contains adhesive bands in the ends that provide excellent strain relief for the wires at the splice crimp, as well as environmental sealing.

Buy a used set of crimpers for these splices and keep them after you are finished. Once you have used these types of splices, you WILL Not go back to standard butt splices on anything.

http://www.newark.com/webapp/wcs/st...003&langId=-1&storeId=10194&gs=true&st=M81824
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I was thinking solder sleeves as the glue seals the ends and provides strain relief, but I like this option. I just about done with wiring, but thanks, I will get some for inventory!
 
As I recall Boeing/Douglas specified standard Amp splices throughout the airframe, the environmental splices were spec'd only in certain locations like pylons and engines. So use them if it makes you feel better but the enviro splices are overkill on an RV IMO (not to mention they are rather expensive and you have to drag a heat gun around with you).

Solder sleeves are for terminating shielded wires, not made for splicing.
 
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Walt said:
As I recall Boeing/Douglas specified standard Amp splices through out the airframe, the environmental splices were spec'd only in certain locations like pylons and engines. So use them if it makes you feel better but the enviro splices are overkill on an RV IMO (not to mention they are rather expensive).

Solder sleeves are for terminating shielded wires, not made for splicing.
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I fully concur.

I see where lots of builder use solder sleeves to splice wires, which they were never designed to do. Solder sleeves do not contain enough solder to make a good solid mechanical connection most of the time, but they sort of work.

Standard aircraft grade AMP butt splices are sufficient if you use the correct crimper, but they are bulky. For the few extra dollars I prefer environmentals.
 
I have no technical argument against high quality all-in-one sealed crimp connectors, as long as the operator has the required tool. I think sealing is of great value, right after crimp quality.

However, at well over $1.00 per terminal, it's a expensive way to join wires. The assumption that makes them cost effective is that they save labor costs. If I was paying Mike to wire something, I'd want him to use the Raychem splices rather than pay his hourly rate for a slower process.

If we treat labor cost as zero in legitimate EAB construction, a little more time is no big deal. It's pretty much a case of separating the crimp and sealing functions by using non-insulated splices and terminals, combined with adhesive-lined polyolefin heat shrink.

Brazed seam terminals (butt, spade, and ring) are available in tin plated copper and nickel plated steel. Nickel plated steel is intended for high temperature applications, but I tend to use them when I suspect vibration might be a factor. You should still use a ratchet crimper, but only a basic one is needed. You're not crimping through an insulation layer, so crimp control and inspection is easy. Quality adhesive heat shrink does a good job of strain relief and sealing. The finished connection is not bulky.

Lots of places to buy. Here are some examples:

http://www.delcity.net/store/Non!Insulated-Butt-Connectors/p_801870

http://www.delcity.net/store/High-Temperature-Butt-Connectors/p_801893

http://www.delcity.net/store/Dual-Wall-Tubing/p_327

Mike H said:
I see where lots of builder use solder sleeves to splice wires, which they were never designed to do. Solder sleeves do not contain enough solder to make a good solid mechanical connection most of the time, but they sort of work.
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Or sorta not ;)

Tried them once...never again. Months later I was chasing intermittent connections, and wound up replacing them all.
 
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Dan, I have a spare set of enviornmental crimpers I can let you borrow. Once you try them....you'll never go back!;)
 
Nothing wrong with splices but... I'm sick of hearing people say a solder joint will fall apart. They don't. The average spam can has about a thousand solder joints. An electronics pro friend of mine used to do avionics on F18's and he would solder for days because THAT WAS THE ONLY JOINT ALLOWED. You know who makes all the claims that solder joints are inferior? It's the guys who make the splices. There's no rebuttal from the "solder makers", so everyone just parrots the company line. So, lets hear about some good solder joints gone bad. Few and far between I'll bet.
 
I agree

High reliability soldering actually works very well. The only areas I see consistently-failed solder joints are on DB connectors. those take some practice, and it is far more reliable there to use the crimp pins and sockets. Besides failures of the solder joints here, the use of pins and sockets negates the chance of shorted wires unless heat shrink is used between all of the pins when soldering.

Vic
 
The old saw that I always heard about solder joints in aircraft was that they will develop wire breaks at the end of the solder joint, since the wire is confined from moving in the solder and thus makes more movement in a very small area right at the edge of the solder, weakening the wire. This is simply a matter of proper strain relief. I have quite a few solders connections in my wiring, each of them supported with heat-shrink tubing for at least an inch either side of the joint, this supplies quite a bit of stiffness in that jointed section that discourages flexing there.

Having said that, I am not a fan of solder terminations onto plugs, since those are exposed to quite a bit more handling an flexing. I crimped all my connectors, using pins and socket in my DB's.
 
There is also what is called a piggyback quick disconnect. I've been looking into these to join 3 wires in certain locations. Basically it is a female faston with a male tab. I think it would work for you.
 
Back to the original post and splicing three wires..

Since people are referencing specifications... do any of the crimp specifications actually allow for two wires into one barrel?
 
az_gila said:
Back to the original post and splicing three wires..

Since people are referencing specifications... do any of the crimp specifications actually allow for two wires into one barrel?
Click to expand...

How about moving up one size on the butt connector. Twist 2 wires together into one side, strip a longer section and double back on the single wire. Or, as suggested, solder and heat shrink. I did that on quite a few 3-wire connections on my Dynon setup. In a loom with a zip tie either side of the joint, I fail to see how it can possibly come apart.
 
In my day job (non-aviation), I have had to find and repair many wire joints gone bad. Most were due to improper techniques of initial electrical bonding allowing corrosion to further degrade the connection causing gremlins. In aircraft, vibration is an additional concern which is easily mitigated by proper physical support. The challenge of any crimp connector (in my opinion) is that of obtaining sufficient contact area which will never be subject to degradation for whatever reason. Solder solves this challenge easily.

In my opinion, the aircraft environment is harsh due to corrosion caused by moisture (condensation) and chemicals. Therefore sealing the point of electrical contact is extremely important. This is something I believe solder does quite well.

I fail to see how a wire joint properly soldered, insulated and imobilized in a wire bundle will suffer from vibration at least on our type of aircraft.

If soldering was not sufficient, all those circuit boards with their gazzillion solder connections would be failing at a much higher rate due to the sheer numbers of connections involved. Which is obviously not the case.

As previously mentioned, one downside of soldering is the labour, but that doesn't really count in our world especially if you have to chase gremlins in the future.

Bevan
 
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RVDan said:
Ironcally Raychem solder splices do allow for 2 into 1 wire. Like others, I have had problems with these for splicing wires. http://www.farnell.com/datasheets/667378.pdf
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Yes, these particular solder sleeves are specifically designed for wire splicing. I have only used them a few times before with mixed results, although that may be due to poor technique on my part. I see pictures posted where some builders use the solder sleeves designed for shield termination to solder slice wires.
 
az_gila said:
Back to the original post and splicing three wires..

Since people are referencing specifications... do any of the crimp specifications actually allow for two wires into one barrel?
Click to expand...

The MIL-S-81824/1 enviornmetal splice shrink sleeves are not designed for two wires into one side. There are different part number Raychem environmental splices that have shrink sleeves containing sealing bands designed for two and even three wires per end, but they are not common, and are prohibitively expensive. Even though the 81824/1 splices do not meet milspec with two wires in one end, they work and seal very well if you simply use the next larger size. I use the blue splices for three 20-22 gauge wires quite often.
 
Mike H said:
No....what am I missing here? I usually use a Snap-On butane soldering iron with the shrinking tip installed.
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Which one do you use? I've never been a fan of using open flames around aircraft but I may have to have a look at one of these if you use it.
 
As an avionics tech in the Navy. And, 4 years as an avionics tech at a repair depot, doing wiring mods on Boeing 7XX and MD-80s, I can say the Raychem environmental splices are the standard butt-splice and shield splice. Use the right crimper, and a proper heat-gun and its as solid a connection as you'll get. The old style Amp butt splices will work just fine, if done correctly and with the proper tools. But, I haven't used them on military or commercial aircraft since the '80s.
 
Walt said:
Which one do you use? I've never been a fan of using open flames around aircraft but I may have to have a look at one of these if you use it.
Click to expand...

I use one of these. https://store.snapon.com/Butane-Sol...-Soldering-Iron-25-to-125-Watts--P647908.aspx

I didn't pay nearly as much many years ago. There are lots of similar butane soldering irons on the market that come with a shrinking nozzle that replaces the soldering tip and blows hot air. There is no "open flame" but of course it should not be used near open fuel lines or fuel vapor.
 
N804RV said:
As an avionics tech in the Navy. And, 4 years as an avionics tech at a repair depot, doing wiring mods on Boeing 7XX and MD-80s, I can say the Raychem environmental splices are the standard butt-splice and shield splice. Use the right crimper, and a proper heat-gun and its as solid a connection as you'll get. The old style Amp butt splices will work just fine, if done correctly and with the proper tools. But, I haven't used them on military or commercial aircraft since the '80s.
Click to expand...

I concur. I have not seen a standard aircraft grade AMP type butt splice used on an aircraft built after the late '80s. It has become "standard practice" to use enviornmental splices.
 
Walt said:
As I recall Boeing/Douglas specified standard Amp splices throughout the airframe, the environmental splices were spec'd only in certain locations like pylons and engines. So use them if it makes you feel better but the enviro splices are overkill on an RV IMO (not to mention they are rather expensive and you have to drag a heat gun around with you).

Solder sleeves are for terminating shielded wires, not made for splicing.
Click to expand...

Mike H said:
I fully concur.

I see where lots of builder use solder sleeves to splice wires, which they were never designed to do. Solder sleeves do not contain enough solder to make a good solid mechanical connection most of the time, but they sort of work.

Standard aircraft grade AMP butt splices are sufficient if you use the correct crimper, but they are bulky. For the few extra dollars I prefer environmentals.
Click to expand...

Funny, I did have to use a few solder sleeves to make a three wire connection (unavoidable 3 wire), and the test piece did indeed not have enough solder (USAF) so I soldered it, then added the sleeve, primarily for strain relief and sealing. Using shrink alone left a gap between the wires, and I did not like that for a splice.

Dang - thought I did a good thing - it was what Steins guys did.
 
BillL said:
Funny, I did have to use a few solder sleeves to make a three wire connection (unavoidable 3 wire), and the test piece did indeed not have enough solder (USAF) so I soldered it, then added the sleeve, primarily for strain relief and sealing. Using shrink alone left a gap between the wires, and I did not like that for a splice.

Dang - thought I did a good thing - it was what Steins guys did.
Click to expand...

There are some solder sleeves that are specifically made for wire splicing. These partcicular solder sleeves have a long, small diameter shrink sleeve similar to an environmental splice sleeve, and they also contain a fairly large solder band. I have used these a few times with mixed results.

I often see pictures of builders using solder sleeves made for shield splicing to splice wires which never works out very well.
 
Mike H said:
The MIL-S-81824/1 enviornmetal splice shrink sleeves are not designed for two wires into one side. There are different part number Raychem environmental splices that have shrink sleeves containing sealing bands designed for two and even three wires per end, but they are not common, and are prohibitively expensive. Even though the 81824/1 splices do not meet milspec with two wires in one end, they work and seal very well if you simply use the next larger size. I use the blue splices for three 20-22 gauge wires quite often.
Click to expand...

I looked at the spec sheet for the MIL-S-81824/1 (D-436-36,-37-38) environmental slices again, and they ARE approved for up to two wires in each end of the splice. So yes they are approved for splicing three wires together.
 
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