Soldering wire connections not recommended.

GoldenMotor.com

ericbowie

New Member
Aug 23, 2015
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Cedar Park, Texas
Hi all.
New guy here. I've been reading through the forum and seeing many members advise soldering their wires together. I respectfully disagree. One should use quality sealed connectors that crimp onto the wires in vehicle applications.

I'm not saying those cheapy little butt connectors are any good. If you're dropping coin on a quality build, a few bucks on a good automotive grade connector is the way to go. Crimping the pins can take a little skill and creativity if you do't have the correct crimping tool.


The problem with soldered joints in a vehicle application is vibration-induced fatigue. the transition point between bare wire and solder, strands will crack and fray.
If you have an electronics device of some sort on a vehicle, it may have headers at the circuit board rather than bare wire soldered to a pad, or the wire is kept from vibrating at the joint with some sort of strain relief. In any case, the idea is to prevent vibration at the joint.

If you're not worried about weather, molex connectors are fine. Shoot a little silicone in the ends to seal it is not a bad idea. If you're an uptight, anal retentive perfectionist, Deutsch are as good as anything. The crimp tool is major $$$ though. If you don't plan on rewiring a lot of vehicles, probably not worth it.


That's my story and I'm sticking to it.
zpt
 
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crassius

Well-Known Member
Sep 30, 2012
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I build some bikes for dealers to sell when repairs are slow. One dealer wants connectors soldered, so I do it that way after explaining to him how hard it makes on-road repairs. For my builds, I make a terminal strip with two sections and put spade connectors on wires. One section takes the blue circuit, other takes the black.

Just a screwdriver needed to unhook a wire for testing.

easy to make by sawing off two sections of 20 section strip

EDIT: oh yeah, strip gets stuck to side of CDI with double sided tape
 

ericbowie

New Member
Aug 23, 2015
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Cedar Park, Texas
I build some bikes for dealers to sell when repairs are slow. One dealer wants connectors soldered, so I do it that way after explaining to him how hard it makes on-road repairs. For my builds, I make a terminal strip with two sections and put spade connectors on wires. One section takes the blue circuit, other takes the black.

Just a screwdriver needed to unhook a wire for testing.

easy to make by sawing off two sections of 20 section strip

EDIT: oh yeah, strip gets stuck to side of CDI with double sided tape
I like the term strip.

BTW, You can solder pins / connectors if you strain relief between the end of the solder joint and the loose wire so there is no relative motion between them. I think the difficulty here is that solder flows up the wire and you have to know how far up it traveled. People with little experience soldering will have a harder time, and it really is overkill.

You can have the same issue with a crimp pin too, really. The exit of the wire from the crimp is a point that can fatigue.

But if you look at the pins of a molex connector, for example, there are two parts that secure the wire. You crimp onto the bare wire for the electrical connection, and there is a part that crimps around the insulation a little farther up for strain relief. This isolates that 'transition point' from relative motion -- no fatigue.

Personally, I do flow solder at a connector pin, but just a bare minimum coating at the crimp only to protect against corrosion. A good crimp is mechanically sound, and electrically it makes no real difference.
 
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bairdco

a guy who makes cool bikes
Aug 18, 2009
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living the dream in southern california
I've soldered at least 25 motors. The only time I had a wiring problem was on my first bike, using the stock connections.

There is a proper way to solder wires together. I'm surprised at myself for never posting it.

So here goes:

1. When cutting the existing wires, stagger them, for example, cut the blue wire off at the connector, and the black one off 1 1/2" farther back. On the other side, cut the black wire off at the connector, and the blue one 1 1/2" back.

This staggers your solder joints so you don't have a big ugly lump with the two wires rubbing together at their joints.

2. Slip the correct size heat shrink over each individual wire, and a larger piece over both wires and shove them down out of the way.

3. Strip at least one inch back on each wire, making sure you strip the same amount from each wire to prevent one being longer than the other to maintain a clean appearance.

4. Bend the stripped portion of each wire in half, and hook them together, twisting the cut ends back on themselves.

This will give you an interlocking joint, of minimal size, that will never come apart. Just twisting the two wires together is ugly, and not as secure.

Before soldering, put a small piece of electrical tape temporarily over your connections and start your bike to make sure it's all hooked up correctly. If it is remove the tape and proceed.

5. Using the thin, flux-free electrical solder, cleany solder the two wires together completely, keeping the wires in a straight line.

I'm not going to detail how to solder. If you don't know, google it, practice, use an iron, not a torch, and get that nice shiny silver joint, not a cloudy, yellowed mess with the jacket all melted.

6. Let it cool, slide the individual heat shrinks on, heat 'em up (again, properly, don't melt them,) let that cool, then slide the larger piece of heat shrink over the whole thing and heat that up.

You should have a perfect, small, aesthetic group of wires that'll stay together forever.
 

Davezilla

New Member
Mar 15, 2014
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I've soldered all my connections on all mine as well as everything else I've owned in the last 30 years... When done right like already stated above, so no need to repeat what he said, the connections will out last the vehicle the soldering was done on.

Soldering combined with heat shrinking makes for a very clean looking install with no issues of poor contact.

If there is a wire that may need to be removed later on I'll use terminals but I solder the terminal to the wire as crimping has already been proven to be unreliable... unless you do use the really expensive terminals and the really expensive proper tool for each terminal.

Soldering has been around for several decades and when done properly it'll hold for several decades with no adverse issues... Now if you don't know how to solder properly read up on it online or take a class because there's a right way to do it and all other ways are wrong. If you're melting the solder on the iron and trying to get it to stick to the wire you need to take a class in a really bad way.

Same goes for crimping, there's a right way and a ton of wrong ways, and each type of connector requires the right tool or it won't hold, those $10 terminal kits at the auto parts store will surely get you a poor connection, but if that's all you got to work with, you can remove the plastic barrels, solder the wire to the terminal, and use a little heat shrink to complete the job and it'll work.

Just gotta remember to stagger your splices like mentioned above and don't forget to put the heat shrink over the wire Before soldering. If something needs to be more resistant to the weather they do sell glue lined heat shrink so it insulates And seals the connection.
 

ericbowie

New Member
Aug 23, 2015
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Cedar Park, Texas
4. Bend the stripped portion of each wire in half, and hook them together, twisting the cut ends back on themselves.
The technique I prefer for end splice is to fan out each end, interlock the facing ends, then weave them together. Following that, take a single strand and wrap it around it tight -- the idea being to make it mechanically solid without solder. Then flow over it and it goes nowhere. An OG technician taught me this when I was first starting out. For illustration sake, I found a guy online that does close to the way I do it...
http://jaguar.professional.org/electrics/splicing.php



IF you guys are having good results, I'm not one to say you should change for change's sake. Even though I generally advise against it, I sometimes choose to solder depending on situation and careful attention to detail.
 
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bairdco

a guy who makes cool bikes
Aug 18, 2009
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living the dream in southern california
I learned my method from the Lucent techs who wire up all the equipment for cell phone towers. Figure if it's reliable enough for millions of phone cals, it'll work on a junky chinee bike.

Quality bullet connectors are fine, but I hate the look of wires of any kind on my bikes, and everything else, so i do whatever I can to hide everything, or make it as visually pleasing as possible.
 

ericbowie

New Member
Aug 23, 2015
18
0
0
Cedar Park, Texas
I learned my method from the Lucent techs who wire up all the equipment for cell phone towers. Figure if it's reliable enough for millions of phone cals, it'll work on a junky chinee bike.

Quality bullet connectors are fine, but I hate the look of wires of any kind on my bikes, and everything else, so i do whatever I can to hide everything, or make it as visually pleasing as possible.
Hide the connector! :)
 

ericbowie

New Member
Aug 23, 2015
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Cedar Park, Texas
I have about 4 decades of soldering under my belt. Works great.
Your anecdotal experience is no defense against the opinion of an anonymous person on the internet! :)


Srsly though, quality work = winning all around. We all have different levels of experience -my profession is in this field and I've been at it a long time as well, if not quite as long as you. I've wired several motorcycles, scoots, and a couple cars from scratch. (Sorry if that sounds like derk-waving, I really don't intend that). I wouldn't every say
"hey, you, lead technician with decades of experience making electrical connections on cars by soldering... stop that!".

But, I definitely advise regular joe shmoe against it. IMO, it's better for most, like 99.9%, not to mess with it. I would argue you are the exception, not the rule.
 
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Davezilla

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Mar 15, 2014
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Same here... I learned to solder the right way in the air force back in 87... Got a degree in electronics in 89 and worked in that field of work for about 3 years before going to automotive maintenance, at the time the job market in San Antonio was totally saturated with electronics techs and most grads from these trade schools were stuck doing assembly work for next to nothing, it happened to me too but I got a lead position after working at one place for about a year. Thinking now that I got a better position I would make more was just a wishful thought... everybody else was making just above minimum wage and I was making about another dollar more than them, It was really sad when I was passing out paychecks and saw this lady's check that she was making 4.90 per hour and was working there for over 10 years. And most the others that were there that long or close to that long were making even less. A lot of them were getting annual raises of between 5 and 15 cents per hour, and all the other places in the area were paying similar wages.This was when I decided to get out and go automotive which doubled my income almost overnight.
I stayed in automotive repairs for about a year when the opportunity to work for Lockheed as a jet engine mechanic came around so I stayed there for about 3 years then moved over to Boeing where a stayed for 15 years as a flightline mech, got laid off about a year and a half ago and used my severance package to open up an auto repair shop.
Having some electronics skills did help both in the auto repair and aviation industries as I could diagnose and repair some of the electrical issues or splice a wire etc without needing to wait for the avionics guys to show up, most the time I would find the problem and get things set up then let them take over when they got out to the plane but I've also done more than my share of repairs when there was no time to wait for them.
I've also seen some of the nastiest solder connections when running the assembly line ,for that first place I worked, they usually hired people either fresh out of electronics school, the military, or from other electronics places but they would also hire just about anyone if they needed a big job filled.
It was not uncommon for me to find finished products with cold solder joints or wires with the solder wicked up under the insulation etc, but trying to show some of these people the right way was pointless, they would do it right until whoever was showing them the right way walked off, then make a few comments about them and go back to melting the solder on the tip of the iron and sticking the ball of molten solder on the components etc, or using the wrong size iron to solder the bigger wires which let's too much heat go up the wire and the solder follows etc...

So far everyone in this conversation I can tell know what they're doing but I wouldn't recommend soldering to just anyone and it's probably better they use other methods to connect their wiring. Of course, it's also a lot easier to show someone who don't know how to solder than it is to show someone who worked on an assembly line for a year or so and was never shown the right way.
 
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2door

Moderator
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Sep 15, 2008
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Thanks guys. This is a useful thread with lots of good points on both sides. I'm also a solderer and rely on that method on my motorized bicycle wiring. However, I have some experience too and know how to do it correctly. When we advise a new builder to solder his connections, all too often we assume it will be done correctly. If it isn't then the results will probably be worse than the kit supplied bullet connectors.

The potential for a broken wire from too much solder (deep wicking), especially one subjected to vibration is a viable concern. We would be wise to examine our advice and maybe add some soldering information when we suggest soldering the ignition circuit wiring.

Thanks again. Good information here and food for thought for a new builder to consider.

Tom
 

Goat Herder

Gutter Rider
Apr 28, 2008
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Your anecdotal experience is no defense against the opinion of an anonymous person on the internet!
Got nuttun to proove simply put I have done it all and worked on it all. My father is a electrical engineer for starters. I learned early on a young lad. My solder jobs don't break. So I am doing something right. This is a point I aim to make..Oh yeah for about four decades now too but I already said that.... I would not have piped in if it was not working lol.


I should add I am proponent of soldering everything ''I care about.'' If it's a car going to a used car lot. Meh use butt connectors without any dielectric grease either. Think Yanky land with water in the air for starters. Desert climate pretty forgiving. Back to the butt connectors..

So some poor sob can have a bad day a few years down the road and spend all day tracking down the issue.

Butt connectors can be great. Done nice with Dielectric grease tho


Machines rattle that which rattles tries to come apart. Do it right and you will not have to cry later.
 

Davezilla

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Mar 15, 2014
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The electrical systems in most aircraft run 3 main busses, a 400 volt, 400hz bus, a 115 volt, 400hz bus, and a 28 volt DC bus in order to run all of the components and systems.
As far as soldering in aircraft, Most the wiring is pinned and connected via cannon plugs, these is some soldering but mostly when a wire is fed into a circuit board, the crimping and pinning process is totally different from automotive and the crimping tools are even required to be calibrated so the gold plated pin doesn't get crimped too loose where the wire could come out, but not so tight that it crushes and cuts the wire. I didn't do any of the crimping of any wiring while working on the flight line since each electrician had to hold special training certs to be allowed to do any crimping or pinning, for soldering only qualified and certified people could solder, and it doesn't matter how much previous experience from other jobs the person has, they do not touch anything until they are trained and certified to do so.
I held over 100 training certs while at Boeing, and what I was certified to do on one aircraft I may not be certified to d on another, and yes, they were that strict. The best cert I had while working there was being engine run qualified on the KC 10. That was both the hardest cert to get and the hardest to keep, and we could lose our run cert just by not doing an engine run every 45 days, if we went 45 days without doing an engine run we had to re test and run under the supervision of an instructor before getting the cert back.
Back to the soldering or crimping process on aircraft, Everything has to be done Exactly the way the book tells you... how to strip the wire, how to clean the wire, how to twist the strands on multi strand wires, how to pre tin it, then how to twist the wires together before soldering, then finally how to make the solder joint, as well as what brand and model soldering iron to use. It's nothing like working in an electronics shop or automotive... every step of the process has to be followed exactly, and in some cases, you need quality checks done in between steps. It could easily take all day just to connect a few wires that would normally take a few minutes, but some of these systems are critical to flight safety so they don't take any chances.... if anyone has seen the price of a small plane these days and wonder how they could cost so much... this is why...
 

Pablo

Master Bike Builder & Forum Sponsor
Dec 28, 2007
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Man I've seen some nasty "crimps" on bike wires over the last 7 years. I always solder and I believe I mentioned it in a thread or two in 2007-2008. I learned to solder around 1985 at China Lake NWC, and you are correct, a stress point is created where your wire tinning ends, and if too much solder wicks up the wire, of course you will create a stress point inside the insulation. But done right with proper stress relief, solder joints outlast the engine.
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
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So some poor sob can have a bad day a few years down the road...
So it was you who wired my caddy. :)

The 65 cadillac coupe deville I had was wired up by a "pro electrician," I was told.

Everything is electric on that car. seats have a two way switch, windows have a master control on the driver side with 4 individual, lockout, and emergency switch to lower them all at once, 3 cigarette lighters, self dimming hi beams, etc...

On any given day, something stops working.

Found out the "pro" used wire nuts, taped splices together, re routed wires...

Total nightmare.
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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I was a big advocate of soldering the wires for many years, but there's been a huge problem with the reliability of the magnetos from many of the Chinese factories in the past few years!

I pretty much just use the factory plug-ins on all my bikes now because it makes diagnosing ignition problems & replacing the defective parts a whole lot easier.

'Lightly' zip-tying the wires to the frame is a good way to prevent damage to the connectors from heavy engine vibrations. ;)
 

ericbowie

New Member
Aug 23, 2015
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Cedar Park, Texas
'Lightly' zip-tying the wires to the frame is a good way to prevent damage to the connectors from heavy engine vibrations. ;)

I'm down with this. Really, we're just talking about bicycles here so it's not like it's a big deal even if someone does muck it up.

I am an electrical engineer, and was a tech before that - I get it. For vehicles I still use Deutsch connectors even though I trust my soldering skills.

E.g., I just resoldered my magneto coil last night, but there's not really a choice. You know darn well I shrink-wrapped the wires to the coil to isolate vibration. I had to wire bikes and cars for track use - it's become a habit to be paranoid. You don't want to lose power in a turn with another car to your rear or inside - it's gonna get ugly.
 
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Davezilla

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Personally on these things I found it best to just solder the bullet connectors to the wires because like somebody mentioned, ya never know when a magneto is going to go out on you and leaving the wiring semi removable definitely helps here.

I did one a few months back where I soldered all the wiring together and heat shrunk everything for a nice pretty clean looking install, the customer loved it but came back a few weeks later with the bike because his brother was too rough on the throttle and pulled the cable end off. No big deal, but when the new throttle came in he wanted the kill switch wired in... This meant cutting off the heat shrink, cutting the wires, re stripping, then cutting the kill switch wires to size, and repeating the whole process. It left the shop again looking nice pretty and clean, but if I would have just soldered the bullet connectors it would have saved me a lot of time and work.