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Soldering vs Butt-Splice conclusions (AUX light wiring w/photos)


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My PIAAs 1100s were not reliably functioning so went in and checked it out.

I stripped the bike, unwrapped the splice, turn the lights on

and check the heat generated at the butt-splices with my fingers. Quite hot!

Heat was created by the "LOOSE" connection which wasn't actually loose, it passed the pull test and thats the point of this thread. BUTT-Splice vs Solder. Read on.



Below are the ground connections which were not warming up.





i'd already started when i thought about posting some DIY info that might be helpful.

this is one of the "hots" previously butt-spliced, i stripped about 3/8" and linked em together....


...wrapped em up...


and soldered, DONT FORGET TO INSTALL THE HEAT SHRINK FIRST (but i think everyone does that at least once)

I applied some liquid flux on the splice, put a dab of solder on the iron and held that dab on the rear of the splice while applying the solder to the front.

(no photo of that though, i only have 2 hands, solder iron & camera)














Upon completion I re-tested the PIAAs, wires were BARELY warm!

All Good!

Thought this info might be useful to someone.










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A good reminder about less than reliable connectivity with solderless connectors in general, as well as 3M Scotchlok (or cheap knockoff) connectors especially which this topic doesn't address. Since my moto buddy Ed ("yattr" :wave:) turned me on to them not long ago, I'm now a convert to minimally invasive Posi-Tap connectors. With multiple wire gauge sizes available, curious if these would have produced similar results to soldered connections? Perhaps not, but no damage issues for reversal if necessary having only produced a "pin prick" into host wire harness insulation...

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Butt-splice connetors are not a problem _Provided_ they are properly made. This needs the right tools. In fact, as soldered joints make the wire more brittle at the point of soldering, butt-crimps can be better. In my industry - defence aviation - soldered joints are not usualy made. We use crimps.

A crimp joint made with the correct (read expeensive!) tool is the best way to do it. Squish up the crimp with a pair of pliers and it will fail.


So, if you have the correct tools and know how to use them, make crimp joints. Of not, then solder is the next best thing.




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Something to keep in mind is that a butt splice connector makes two connections (and two places to fail) and the crimp should always be made with a quality tool designed for the job...something like this.


I worked as an installer for systems where crimp connectors were used heavily. I've made tens of thousands of crimp connections on small gauge wiring. Something I have noticed over the years is that the quality of connectors available has drop off significantly. We would only use very high quality connectors since any problems with the connections could be very difficult to find. The boss tried to go cheap on the cable and connectors a few times, but the installers/technicians made it clear to him that the lower quality crimp connectors were a concern during installation and even worse would continue to be a concern after installation was completed.


I pretty much solder all connections now, but that is a something that can be tedious and sometimes access is a problem. A proper soldering job requires specific techniques, equipment, and supplies. There are some good written tutorials on line as well as good videos on YouTube.

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Off topic:


I can't put it off any longer! In the avatar, is that CVN65?? Island looks square, like pre-her last overhaul. Bet her CO loved seeing a pic taken at that range!


/back to the thread

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I live near salt water... I like solder as it less susceptible to corrosion.


I do use crimps with heat shrink when in a hurry.


Issues with solder-

1- cold solder joints- the solder didn't flow right and it looks frosted. Very prone to failure.

2- yes, it can be stiff, but I've not had one fail..


If I have time/patience, I will slide heat shrink on, solder, then slide hear shrink over. Before I shrink it, I like to put some RTV into the joint. When I shrink it, the RTV squeezes out, and seals the joint. I've wired several boat trailers this way....BIG improvement in wiring reliability.



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