Soldering Bus Wires

[ACL Wayne]

This discussion seems to have started with the question of connecting 12 g [insulated] copper wire to a second length of insulated copper 12 g wire. Then a contributor brought up connecting 22 g to 12 g. In both cases we are talking about "splicing" wire together. How you make the splice should depend on its configuration and whether or not you have need in the future to take apart the splice.

I am assuming that the 12 g copper is continuous and the idea is to tie in the 22 g wire at various locations along the 12 g wire run. If this is the case, what is needed is what we call a "tap splice". Wire nuts (solderless connectors) cannot be used because we are not breaking the 12 g bus wire. After we shave away the insulation on the 12 g wire and the end of the 22 g wire, we have our choice of soldering the cnnection of using a mechanical device. If you expect strain to be put on the 22 g tap wire, solder the splice. Using a big, high wattage iron and rosin flux with 40/60 or silver bearing solder is good. We have used resistance soldering units on large splices. You clamp onto the bus as close to the splice as you can, flux it, and touch the probe to the splice. Usually, in a few seconds the solder flows and the splice is ready to wrap with tape. I have wrapped a short length of small diameter solder around the joint before fluxing to good advantage. If you use a soldering iron, apply it to the bottom of the splice.

There is a good variety of clamp-on devices for making tap splices, as others have indicated. They work by forcing small, sharp points through the insulation of the wires when the devices are clamped together. This saves time by not having to remove insulation, and nicking the 22 g wire, as well as not having to solder and reinsulate the splice. "Pilot" is right about crimp type connectors.

[Anonymous]

Suitcase connectors are available at Home Depot. Even better are positaps, but you have to order them. Make sure you get the right size for YOUR wire. Houses are wired with crimp type connectors with very few problems.

[BlueHillsCPR]

I use a pair old lineman's pliers to twist the wires together and then use wire nuts to secure them. I figure if they're (wire nuts) good enough to wire a house together, they should be good enough to wire a low-voltage MR layout. and they have been for over 25 years.

Wire nuts or Marrettes when used correctly, are fine for wire that is 18GA or larger.  When working with 20GA or smaller wires I would not use them because the small wires are more prone to breakage as a result of mechanical stress/damage. Just my

[modelmaker51]

I use a pair old lineman's pliers to twist the wires together and then use wire nuts to secure them. I figure if they're (wire nuts) good enough to wire a house together, they should be good enough to wire a low-voltage MR layout. and they have been for over 25 years.

If you are soldering, be sure your soldering tip is clean, tinned and shiny. If it isn't it's not going to transfer heat well. Radio Shack sells tip cleaner.

[wccobb]

Been my experience there are two things needed for a good solder joint:  Preparation & Heat.

The surfaces have gotta be clean.  Even copper & brass can "oxidize" - which don't solder good.

You gotta have a good mechanical connection between the wires.  Think of the solder as the something which reinforces that connection.

Cover the connection with a rosin soldering flux.  It goes on BEFORE the heat!!!  Metals "oxidize" much faster when they are hot & the flux seals the joint from the air (read that: oxygen).

Several of the guys got it right: get that iron or gun HOT before you touch it to the connection.  While its heating, "tin" it.  Get some molten solder on that iron or gun. I've got an ancient WEN gun -- pull the trigger & count to 5 -- build up the molten solder on the tip while counting -- then lay it on.  With this deliberate "super-pre-heat", in one or two seconds the solder will begin to flow into the joint & I feed more a bit more from the solder spool -- on the opposite side.  One or two seconds more and its done. Done so fast that often with no visible effect on the wire's insulation. 

I can't stress enough that it's good preperation and a really fast touch with a very hot iron (or gun).  I've even soldered 12 ga wire joints with a propane torch.  The guy didn't trust wire nuts, so, OK -- I soldered all the connections in his whole house, then wire nuts.  And, with lots of heat, never melted any insulation!!!

Good preperation & plenty of heat -- the two "tricks" I learned some fifty seven years ago at EMD while soldering the connectors to the cables which feed the power to the traction motors of the GP7s and the SD7s.  Works well then & works well today. 

[C&O Fan]

I used simple wire nuts as a temporary fix till i was sure all my track was where i wanted it to be

I still haven't done any soldering 2 years later

BTW i hate Soldering

[chugchug]

Yes, I think you guys have summed it up right.

Rosin core solder is a must and a very clean solder iron with the tip "tinned"

with a slight amount of solder (so that it transfers heat to the wire) is also

very important.

I am not a fan of suitcase connectors either.

[Beowulf]

Suitecase taps and various other crimp-on connectors have been workibg great for me since 1995.  On a previous layout which my father and I started in 1953, we used 60-40 solder, "No Krode" brand rosin paste flux, and a huge old soldering iron.  I never knew its wattage but it would easily melt bar solder which was about 1/4" x 3/8" in cross section and a foot long.

We never had problems from cold solder joints but after a couple decades did have corrosion problems.  We were told it was from the natural acids in the tallow which was mixed with rosin to make the rosin paste.  We switched to dissolving rosin powder in alcohol -- a bother as it kept drying out.  But we continued to experience failure of the original solder connections until a move necessatated that the layout be dismantled.

[jim22]

You need an iron with plenty of power AND a fairly large tip.  A temperature controlled iron might be best.  That way, it heats up to a settable temperature (maybe 650 for this job) and then doesn't overheat the tip.  The large tip can supply it's stored up heat to the wire for soldering.  It is important to use enough heat or you may get a "cold solder joint".  These are usually frosty looking and the wires are not bonded together.  Flux really helps too.

I tried to think of a better/cheaper/faster/easier to debug/reliable way to do this, but ended up just soldering.  I don't think I trust the suitcase connectors, and I had trouble finding any that would join 12 ga to 20 ga (maybe 22, not sure).  I had considered the bus bars you can purchase a the home centers for wiring neutrals and grounds to circuit breaker boxes, but even those were a bit expensive.

I used an old Ungar element with a chisel shaped tip about 1/2 inch across.  It was not temperature controlled and got so hot I had to unplug it periodically.

Jim 

[betamax]

Hi group,

Well, (Kevin) we got our new forum. I'm glad it worked out. Thanks to Bergie for making it possible. I just started hooking up my new Super Chief system today. I'm taking my time doing it to avoid as many mistakes as I can. I started soldering 12ga. solid copper wire from my 12ga. bus lines to the DCS-100. I had a heck of a time getting a good solder job. I cleaned the wires good, used flux, 50/50 solder and a good gun. I'm proficient at soldering so I must be missing something. Wrong solder?.............??? Any ideas?

Thanks, Paul

You need a lot of heat. The wire can soak up a lot before it gets to the melting point of the solder.

The wires should be clean, and twisted together if possible, and a little flux (ROSIN!) will help. But for that gauge of wire, you need a hot iron, preferably with a large tip (for the thermal mass.) Solder labelled 60/40 may be a little easier to deal with in terms of it's freeze point.

I had a ton of fun trying to solder feeders onto a transformer, using 12 or better wire. I had an iron with a tip at least a half inch across, and it still wasn't easy getting a decent joint. I could live with less than perfect, as I scrapped the transformer as soon as I was finished testing it. Just needed a connection.

[yankee flyer]

Well guy's I'm still using my Airforce issued "resin" core solder from 1969 to solder my 14 gauge buss wire and I had to resort to my propane torch with solder tip to get enough heat for a proper joint. Just watch out for that sideways flame.

Snow is coming down so I'm really

wishing for Blue Skys

Lee

[Rotorranch]

I use the liquid rosin flux, marketed by "Specialty Race Tires", and commonly sold at slot car raceways, and Radio Shack 60/40 rosin core solder. It works for me!

I have several Ungar/Weller 45 and 50 watt soldering irons with different size tips. Also a Haako 50 watt iron. I use a ceiling fan speed control to lower the temps if needed, for lighter jobs.

Rotor

[BlueHillsCPR]

The rosin (not resin) in rosin core solder...

Rosin, Resin, it seems to depend on who you talk to/deal with.  Dictionary.com seems to find the terms Resin and Rosin, fairly interchangeable.  Either way it's the goo that flows out of the solder when it's melted.

[BlueHillsCPR]

FYI:

Rosin IS flux.  Rosin core solder has flux in it, separate flux application will not hurt anything, but is not required.

For the most part I agree, although in some cases the "core" flux is a case of too little too late, though not all that often. Usually if a connection is properly cleaned before soldering the core flux is good enough.  Either way it should only be resin core.

Incidentally, Tim Warris of Fast Tracks, uses acid flux in his his demo video and only advises washing the completed turnout under running water and perhaps some soap.  Can't do that with bus and feeders.

Thanks, fellas, for taking the time to tell me that I made a mistake.  

BTW, it is resin core solder, and only the flux is acid.  Won't make much diff, I suppose.

-Crandell

Washing the connection would help.  I don't know if that would absolutely prevent the acid flux doing it's stuff but it would help.  There are liquid and paste resin fluxes available I believe.  The bus wire connections may be ok for a long time.  Where you really want to avoid using the acid flux is on electronic circuitry.  That is a nono.

 

[howmus]

FYI:

Rosin IS flux.  Rosin core solder has flux in it, separate flux application will not hurt anything, but is not required.

Right on the spot.  I worked for a phone company during college and would also advise - NO ACID CORE solder.  The rosin (not resin) in rosin core solder is only an acid when it is liquid so it will not corrode wiring.  The rosin is the flux...  If you want to add more flux to the joint, you can buy rosin flux like this one from MicroMark: http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=83473

I have never used the suitcase connectors, but think you would be better off with them than trying to solder on #12 solid to #12 Solid.  I have used terminal strips to make troubleshooting much easier.  I can very quickly isolate a problem on the Bus without cutting wires and then having to solder all over again. 

[Pruitt]

Another problem, Paul, might be your iron. It might not be putting out enough wattage to heat that big a connection sufficiently, or it could be that the tip temperature is too low to give sufficient "overhead" to the job, so it and the work don't have enough heat to do a good job melting the solder. (Two different problems with the same result - not hot enough at the joint).

In the first, the iron can't heat as fast as the joint sucks the heat away, so the joint won't heat up enough.

In the second, the tip starts out just barely hot enough, but cools as the joint sucks up the heat. Again, the joint is too cool. But this time, if the iron has sufficient wattage it will recover and finally heat the joint, but by that time you've fried all the insulation around the joint and you still have a mess.

 Solution - an iron with a tip temperature high enough to provide a big impule heat to the joint, heating it enough to melt the solder well. Even as the tip is cooling down under the heat sink of the joint, it heats the tip beyond the melting point of solder, so you still get a good solder joint. When you remove the iron, it recovers and in a few seconds is ready for the next big joint.

I have a Weller 35 watt professional soldering iron which reaches a tip temperature of a bit over 800 degrees. Plenty of overhead, so it can handle the big joints.

[Phoebe Vet]

FYI:

Rosin IS flux.  Rosin core solder has flux in it, separate flux application will not hurt anything, but is not required.

[selector]

I haven't lived long enough in the hobby to have to come back, hat in hand, and admit that you guys were right.  I wouldn't for a second disagree with you...enough of you have told me to expect problems.  So far, though, so good.  I have to learn this one the hard way, I guess, but that means waiting until I start to get the failures.

Incidentally, Tim Warris of Fast Tracks, uses acid flux in his his demo video and only advises washing the completed turnout under running water and perhaps some soap.  Can't do that with bus and feeders.

Thanks, fellas, for taking the time to tell me that I made a mistake.  

BTW, it is resin core solder, and only the flux is acid.  Won't make much diff, I suppose.

-Crandell

[ChrisNH]

For my bus lines I used stranded, it takes the solder very nicely.

Just curious, why are you soldering to your DCS100, it would seem that just using the strip they provide (I presume you get the same one that came with my DB150)  would allow you to more easily remove the unit if you needed too..

 

Chris 

 

[BlueHillsCPR]

Selector:

It's your RR, so I would not presume to tell you not to do it, but in US Navy Electronics School, I was taught that acid flux and acid solder are a giant no-no.  As a result, I have never tried it, and never will.

I didn't learn this in the Navy but I would have to say

Everything I have ever read/heard says that your electrical connections WILL corrode and cause headaches and actuall damage eventually.

Just my though...maybe being a mod gives selector other special powers enabling him to contradict the rules the rest of us must live by?

 

To each his own of course, but I have never cared for suitcase connectors myself.

[jamnest]

I use 12ga solid copper wire for my DCC buss. I use 18ga feader wires.  I use terminal strips and suitcaese connectors between the buss and feader wires.  At one time I ran a short section of 18ga wire from my DCS100 and DB150 to the buss and used a suitcase connector to connect the wires.  The system ran fine with no problems.  I found that the 12ga soilid copper wire will connect directly to the DCS100, which is what I now do.

JIM

[Phoebe Vet]

Selector:

It's your RR, so I would not presume to tell you not to do it, but in US Navy Electronics School, I was taught that acid flux and acid solder are a giant no-no.  As a result, I have never tried it, and never will.

Of course, that is the same school where they told me "...and if all else fails and you just can't figure out what's wrong with it, put 220 across the antenna and tell them lightning struck it."

lol

[BlueHillsCPR]

You got it in one - wrong solder.  For wiring, you really want 60-40 (or 63-37) electronic solder.  50-50 is good for soldering plumbing with a torch, but rather less than ideal for electrical work.

Chuck (modeling Central Japan in September, 1964)

That would do it allright.

[BNENGR]

Thanks Chuck. That makes sense. I'll get some 60/40.

[tomikawaTT]

You got it in one - wrong solder.  For wiring, you really want 60-40 (or 63-37) electronic solder.  50-50 is good for soldering plumbing with a torch, but rather less than ideal for electrical work.

Chuck (modeling Central Japan in September, 1964)

[BNENGR]

Hi Selector, Thanks for the comeback.

My main bus wires are 12ga.solid copper. I was trying to solder 10" lengths of the same 12ga. wire to the bus wires. The drops went to the DCS-100. Make sense? Could you recommend what type of solder would work best for this application?

Thanks, Paul

[selector]

Hard to say.  I don't understand, first, quite what you describe....12 gauge to 12 gauge?  Hmm.  Anyway, I wrap bared 22 gauge ends (I use solid) around bared sections of the heavier bus wire, and then swipe it with an artists paint brush impregnated with flux.  Then, with 35 watt pencil iron good and warmed up, I lay the tip along the wrapped 22 gauge for a slow count to five, then touch the solder to near the tip of the iron.  In a second I have enough solder there to keep a good claw wrapped around that join.  Mine stay put...well, except for one that was awkward to do in the first place.

Shhh...don't tell anyone, but I use acid flux.....SSHHHHHH!! 

[BNENGR]

Hi group,

Well, (Kevin) we got our new forum. I'm glad it worked out. Thanks to Bergie for making it possible. I just started hooking up my new Super Chief system today. I'm taking my time doing it to avoid as many mistakes as I can. I started soldering 12ga. solid copper wire from my 12ga. bus lines to the DCS-100. I had a heck of a time getting a good solder job. I cleaned the wires good, used flux, 50/50 solder and a good gun. I'm proficient at soldering so I must be missing something. Wrong solder?.............??? Any ideas?

Thanks, Paul