golf4two

Seems that every plane I build requires servo lead extensions and "Y" cables. Most of the way thru a new build that requires both, Since servo connectors become oxidized (which requires unplugging and replugging several times to clean them) I though I might clean up the installation and eliminate at least some of those connectors by soldering in servo wire (for the extension) and, while I am at it, just connect the two leads into a "Y" connection that would reach right to the receiver. First question: Both 22 and 24 gauge wire is available in rolls. Since I use all manner of servos (micro to standard size digital) I would assume that the heavier (22 gauge) wire would be the best for general use? Second question: At the juncture ("Y") point is it OK to just solder the appropriate wires together, properly insulated of course, or is some sort of electrical device required on any of the wires? Although I own many of them I've never taken one apart to investigate--some appear to be just solder joints, others are encased in some plastic case. Also: Any precautions other than the obvious? TIA. G42

KW_Counter

G42,

Yes, the 22 gauge would be better.
No electrical device is required unless you're trying to reverse one of the servos.
Make sure you twist the wires together tightly before soldering.
Soldering is an electrical connection, not a mechanical one.
The twisting gives more mechanical strength than just soldering.

I usually bend each wire into a j-hook, hook them together and then twist.
Plenty of strength and less bulk.

Good Luck,

KW_Counter

jetmech05

As an Avionics tech twisting the wires is not always a good thing.
Make the j hook tin the wires then hook together and solder.

JohnBuckner

My Feedback: (1)

Yes doing custom harness is a normal approach for many of us and is a perfectly safe perhaps even safer approach to some airplanes. My standard method with a high percentage of my airplanes as well as the ones I do for others is for example to: on ailerons of most airplanes simply cut the lead of the new servo in two and solder in a new length of servo wire as needed. This obviously requires six solder joints and can be done quickly with the right tools and a little practice.

For this simple extension do not twist the wires that will only cause difficulties. Instead just remove the insulation back no more than 1/8th at each end and tin the lead then hold one side of the lead with a clamp some like the extra hands tool, I just use an old wooden furniture clamp and hold the other tinned lead straight along side the clamped lead and heat the two leads with the iron to flow the solder. Oh do not forget to slip a 3/8ths length of electronic shrink wrap before soldering the lead and then simply shrink with a lighter after soldering.

Now for the custom Y cord. I have done a lot of these all the way up to a six way Y for a six engine airplane (yes it works just fine) as well as four and three engine airplanes plus many twins.

This is the one time that I do not try to do an inline solder joint but when three leads are to be soldered in paralell doing so inline is difficult and in some of the more complicated situations you may be soldering on the airplane itself. So in this situation I do trim the leads back further and twist the three wires together lightly as if one were going to use a wire nut but of course shrink wrap was just slipped over the three solder joints of three leads each and heated to shrink.

Oh and I always buy servo wire in bulk and use the heavier gauge even if the servos original gauge is smaller.

John

Rodney

John's advice in post #4 above is right on, an excellent way of doing it. It is easy to make a jig to hold wires together by using the snap cloths pins readily available in most areas. Being wood, they do not create any problems in sapping the heat away from the joint when reheating the tinned wires.

JohnBuckner

My Feedback: (1)

Here is an example for a harness to be used for one half of a six engine airplane and looking from the plug end the first two throttle servos for the inboard engines are soldered with three a three way twist and (as if a household wire nut were to be used but then just shrink wrapped. The last servo on the string which is the most outboard engine requires only a simple two way in line splice and soldered with out any twisting but of course the three joints are each protected with shrink wrap.

The same technique can be used for any kind of extension whether in the fuselage or wings, what ever. Just remember to allow planning for a plug wherever absolutely necessary to allow for simple component separation to meet transportation needs.




John

golf4two

Thank you all for your comments and advice, especially you John for all of the detail. I guess I was on the right track.
I'm not the world's greatest solderer so when making a critical connection I usually cut a small length of the stranded wire then remove a single strand. Tin both ends to be joined, lay parallel, then wrap the single strand tightly around both, then solder. Makes the joint a little thicker but it works for me. (Is there a soldering tutorial out there??? Deans connectors drive me batty!) Thanks again Gentlemen, G42

jetmech05

A good solder connection begins with a good mechanical connection

jester_s1

golf4two- assuming everything is clean and your iron puts out enough heat, problems getting solder to flow into a joint are usually caused by a lack of flux. I pulled my hair out trying to do simple electrical connections until I bought a can of paste flux for electrical wiring. It doesn't take much, but with pre-fluxed wires the solder flows in instantly. A little dab on a Deans connector works too. I actually just put a ball of solder on my iron for them and touch it to the flux to tin the connector. It's easy to see when it's hot enough to stick properly because the edges change shape. I've always been told you're supposed to heat the material then let the material heat the solder, but with Deans connectors I've sat there for 2 minutes before trying to get solder to flow that way.

Rodney

Jester has given you some good advice on suggesting that you use some good flux. It makes soldering well so much easier. As to strength, when soldering wires together (like when extending the length of servo wires) just pretinning the bare ends, lay them side by side and reheat to flow the solder is more than adequate for strength. It does not nead a mechanical attachement first like twisting or making interlocking hooks. Just make sure the wires do not move relative to one another until the joint has resolidified.

golf4two

I have a pencil type (40W I think) and a gun type (40/60W I think). I believe that I'm supposed to use a ?resin? (sp) as apposed to acid type flux, correct? Any particular brand that's especially good or bad? Also that I should be using a silver solder? Like most homeowners/hobbyists I've accumulated several types of both solder and flux and not sure what type any of it is anymore. Maybe I should just can it all and start anew with a trip to Radio Shack for a new supply. Need more shrink wrap anyway. Thanks for the tip on the Deans connectors.

JohnBuckner

My Feedback: (1)

Never ever use acid core solder on electrical wiring only use 'rosin' core solder and/or a paste type flux labeled for electrical wiring. Acid core solder is quite effective for soldering structural situations that are not subject to causing corrosion to wire conductors. Things such as piano wire landing gear or cabine sturts with soldered joints and copper wire wraps to flow solder and secure piano wire joints.
Flux and solder is not really subject to going bad so no reason to discard them if you know what types they are. Even paste type flux that has be left with the cover off years and is no longer really a paste any more will work fine just by sticking the tip of the hot iron into it.

John