Soldering question

[jussi]

How you solder 2 wires together for maximum strength but still keep a small profile. I'm working on my multirotor and have some experience but wanted to know the proper way to do it. There might be some stress on the wires as I work on the copter over time and I want to make sure the joints don't fail. I will be working with 16 and 14 gauge mostly. I would also like to make the joints as small as possible as the wires have to go through a boom arm so I can't have the joints take up too much space. From the videos I've seen it seems like most people either braid the wires together without tinning first then solder or tin the wires first the fold each into a U shape and then solder. I tried the latter first but the resulting joint was too big. In sure a lot of that was my lack of technique.

[dkerfoot]

If you have room, offset the soldered joints so that one wire is soldered 1/2-3/4" before the other. In these cases, I prefer to not tin the wires first, but wrap them tight, then solder. You don't need anything approaching a solder glob - the joint should be no larger after soldering than before. The goal is that the wires provide the mechanical connection and the soldering just works to preserve the electrical connection.

Jump up one page from this link and view the "Western Union Splice" and the "Staggered Splice"

https://books.google.com/books?id=Kg...0wires&f=false

[LCHIEN]

Wow, 14 to 16 gauge wire in an model aircraft? Seems huge to me, what is the current carried in this wire?
WHat is the voltage and length of the wires? (Electrical engineer curiousity)

I assume this is stranded wire? I also presume UL standard PVC insulation of 300V (not 600 would be overkill...)

For compact wiring of thick wires like you have I would simply slide a piece of 1" long heat shrink tubing over the insulation to one side and strip about 1/2" off each end, twist the stranding to keep it tight and tin lightly so you can see the stranding. Then (this takes three hands) put the two ends side by side (from opposite sides) and tag with the soldering iron (don't add solder) so that the two ends sweat together parallel. Blow on it to cool the solder in place before letting go. You should see a nice shiny joint that is every bit as strong as the wire.

One of those third hand holder thingys can help.
I'm still surprised you wire is so big... unless its a huge drone.

Then slide the shrink over the joint and hit it with the heat gun for insulation. You'll have a splice only about .020 bigger than the wire.


If you can get teh wire down to 22 or 20 ga then this method works to twist the wires to gether
http://www.instructables.com/id/Mast...ice-everytime/
I think that's the same as Dkerfoot was recommending. But its hard to do with 16 ga.or 14 ga wire!

[jussi]

Thanks dkerfoot. I used your suggestion and it worked out great. Looks like plenty of strength with minimal bulk.

[jussi]

Loring. I was mistaken it was 16 and 18 gauge. The ESCs and Motors are already wired so I'm just using the same gauge they came with. The ESCs max out at 30A but I think the max the motors use is like 18A at full throttle. The battery I'll be using for now is 6s 4500mah 25-50C. Though in the future is like to go to twin 6000mah (or higher). It's a somewhat medium/large quad. 650 class. So 650mm from center of propeller to center of propeller diagonally. Using 14" propellers but only because I couldn't find any 15" locally. I'll take a pic when I'm done. Thanks for the advice and thanks for hakko fx-888d recommendation. Love the soldering iron

[cwsmith]

One of the first solder joints I learned as a kid was the "Western Union Splice". It's stong and can be done on very small wire. What I like best is that if done properly, it can be mechanically strong and even if the solder-joint is poor, vibration won't tear it apart.



I hope this helps,

CWS