Soldering Track Drops...

[Sumner]

Soldering Track Drops...

With the track down for the sawmill scene area it was time to do a lot of wiring. There are track drops from all sections of track since I don't solder the rail joiners between the turnout ends and the ME code 55 flex track. With 17 turnouts in this area that meant a lot of wires running to them, to the frog polarity servo bracket limit switches and to the flex track between the turnouts (over 40 track drops).

 

I drill holes just big enough for the 22 awg solid wire I use. Then from the wire spool I run wire down through the hole. Reach under and pull it to the side of the layout where it will later be soldered to the buss. Cut the wire off, pull it out from the hole a bit, bend it over and strip about 1/2" of the insulation off.

 

I pull it out further and put a short 90 degree bend in the end and bend it back so that it will contact the side of the rail easily. I hold the wire to the rail and put a small drop of Superior #30 liquid flux on the wire/rail joint. The flux is crucial as the solder will flow very quickly onto the wire/rail joint when the soldering the joint. This is not an acid flux and doesn't have to be cleaned afterwards but if you are using one that does need to be cleaned be sure and do that. I love this flux and use it for all my electrical projects. A little hard to find but do a Google search.

 

In the next step I'll solder the wire to the rail but first. Between almost every solder joint I make, here or on other projects, I clean the iron right before it. I dip the hot iron in one of the small tins of tip cleaner (not shown above) and then wipe it on the wet sponge. The tip should then be shiny silver. It is isn't you are going to have a hard time soldering. Again, I do this for every solder joint just before using the iron. It is a lot of quick cleaning but pays off in easy soldering. I've tried other tip cleaning methods but the sponge still works best for me.

Also I have more expensive irons but these are only $15 on the internet and work great and extra tips are really cheap and quick to replace. Once you can't get solder to stick to your iron change to a new tip. I use a 100 watt iron for these track drops so that I'm on and off in a second or less which then doesn't melt the ties unless you touch them (which I do occasionally). I use a 60 watt for all my other projects. I keep both irons on 'full' hot so that the solder joint time is very short. This keeps the ties or other components from overheating.

I'm using .8mm rosin core solder for the drops and .6mm rosin core for everything else.

 

With the wire pre-bent and the flux on the wire and rail and a clean iron with a small drop of solder on the tip the soldering will happen in one to two seconds. Hold the wire on the rail. Touch the iron tip to the end of the solder for just a touch of solder. Push the tip with the drop of solder on the tip against the wire/rail and the solder should flow almost instantly. As soon as you see it flow pull the iron away. No melted tie unless you touched.

With an iron at a lower temperature you will be on the joint a longer time and the heat will transfer to the tie.

 

If you want to solder to the bottom of the rail you could do that also. Slightly different steps. I have too much to do to take that approach and with a drop of paint on the solder joint I can't imagine very many visitors ever seeing the drops. They are too busy looking at everything else. At least that seems to be the case so far.

 

Above you can see half the drops in the sawmill scene. These go to solder pads ......

 

..... on one side of the layout with another set of solder pads on the other side. The outside main track here is in a different power district that the majority of the track in the scene. Since a DCC-EX Command Station can put out DC and DCC to different districts (8 in my case) at the same time I'll be able to run a DC loco on the outer main track and one or more DCC loco in the rest of the scene at the same time.

I didn't go with buss wires...

 

.... like I did on the lower level (above and ( HERE ) ) as the fascia isn't wide enough on the upper level here so that there is good access to the hidden staging below. The solder pads work well as I can connect a lot of wires together and the DCC from the command station in a very small area.

To be continued and a link to this whole build ( HERE ) .

Sumner

[robert3985]

On feeders that I solder to PCB ties, to make them less visible, I flatten the end of them enough so that I can put a 90deg bend on them, snip the very end square and a little shorter than the width of the tie, and solder it down.  This is much less visible than round wire.  I use my "precision" flat-nose pliers for this, so it doesn't require much force.  Most of the time, using Superior No.30 Supersafe, if the top of the tie is tinned a little from soldering the rail on, that's enough to secure the feeder.  I also use 96/4 Tin/Silver silver-bearing solder because it's at least 5 times stronger than Tin/Lead electrical solder...and also has much better conductivity.  The extra strength means I don't have to worry much about pulling the feeders off...or if my cats decide to do chin-ups on the wiring down below!

I really enjoy watching your layout progress!

Cheerio!
Bob Gilmore

[peteski]

Sumner, I would like to present some observations.
I also consider myself a king of overbuilding, but as I see it (even from that angle), there still is a degree of overbuilding which would be excessive to me.  Here is some technical information for someone who might read this thread to make up their own mind about the degree of overbuilding the want to achieve.  As I just mentioned in another thread, here is the info:

Getting the technical info  from https://www.powerstream.com/Wire_Size.htm here are some examples.  Assuming the feeder length is 3' (6' round trip), here are the voltage drops in the feed itself:

6' of 22 AWG  wire - total resistance 0.097 ohm - voltage drop @ 0.5A = 0.048V or @2.0A = 0.19V
6' of 24 AWG  wire - total resistance 0.154 ohm - voltage drop @ 0.5A = 0.077V or @2.0A = 0.31V
6' of 26 AWG  wire - total resistance 0.245 ohm - voltage drop @ 0.5A = 0.122V or @2.0A = 0.49V

In N scale, an average sound decoder-equipped locomotive with a conventional permanent-magnet motor will draw less than 0.5A of current (even less with coreless motor). I also gave voltage drop @ 2 Amps for multi-unit lashups.  To me even 24 AWG wire would not result in excessive voltage drop. Of course with shorter feeds, the voltage drop will even be less, and more for drops more than 3' long.

Even for longer feeds I would not feel the need to go higher than 24AWG as I consider using 24 AWG wire for short drops in N scale as having very comfortable current carrying headroom. For shorted feeds (like 16"), even 26AWG wire would be more than sufficient.

Also for some reason the 22AWG wire you have has what seems like extremely thick insulation which requires rather large diameter holes in the layout. If it was me I would have tried to find some withe with thinner insulation to make things easier for myself.

I also like to mention that the electrical bus made up from conductors which carries electricity (just like the vehicle carrying passengers) only has one "s".  "Buss" is an old word for "kiss". See https://www.merriam-webster.com/dictionary/buss  and https://www.merriam-webster.com/dictionary/bus .

I see this misspelling fairly often. I suspect it might have originated because there is a Bussmann brand of electrical components, like fuses, so people assume that the electrical bus is spelled with two esses. The brand is now owned by Eaton. https://www.eaton.com/us/en-us/products/electrical-circuit-protection/fuses-and-fuse-holders.html

[JeffB]

Sumner, I would like to present some observations.
I also consider myself a king of overbuilding, but as I see it (even from that angle), there still is a degree of overbuilding which would be excessive to me.  Here is some technical information for someone who might read this thread to make up their own mind about the degree of overbuilding the want to achieve.  As I just mentioned in another thread, here is the info:

Getting the technical info  from https://www.powerstream.com/Wire_Size.htm here are some examples.  Assuming the feeder length is 3' (6' round trip), here are the voltage drops in the feed itself:

6' of 22 AWG  wire - total resistance 0.097 ohm - voltage drop @ 0.5A = 0.048V or @2.0A = 0.19V
6' of 24 AWG  wire - total resistance 0.154 ohm - voltage drop @ 0.5A = 0.077V or @2.0A = 0.31V
6' of 26 AWG  wire - total resistance 0.245 ohm - voltage drop @ 0.5A = 0.122V or @2.0A = 0.49V

Pete...

I was always under the (possibly incorrect) impression that stranded wire is better for DCC than solid.  Is this really the case?  Or just an outdated line of thinking?

Jeff

[$2 Bill]

If using 5w to 40w irons... Often the tip will mater like 25-40w iron to get track joint hot without melting more plastic ties etc.
Pointed tips often heat big parts, track or big anything, slowly.
Various Chisel tips may work better including ones that look like pointed tips at quick look but end is sort of small "screw driver" shape.

"Weller" Inductive guns can heat fast and without sucking power for hours. Real Weller and "Knockoffs" have so many kinds and watts to list easily here. Many get/have used Wellers and think all are same but no. Even Weller Guns have different Watts from ~ 70w to 200w depending on model. Some Weller guns are 1 step triggers while others are 2 step triggers with low & high watts.

Problem with "Weller" guns like with iffy Tip clamps then the tip will heat slowly or never. If you have Nuts on "Vintage" Weller guns to hold the tip then many just use force when tips don't heat but just cut the copper. Current Weller Guns got "cheap" many years ago and tip is held by screws and easy to wreck the clamp, tip or both. In either case you need to take out/off the tip and clean or replace iffy parts to get it working again.

Often need Flux even with Flux Core Solder. Yes more cleaning after but added flux often helps a lot more so on parts that are hard to clean before soldering. "Rosin" & other "Electronic" Flux while not Acid can cause corrosion problems as can help moist air attacking parts so still need to clean.

If a cat etc can pull a joint off easily, is something wrong when you solder. Standard 60/40 lead solder will not do that unless the joint is "Cold" or have other problems making the solder to seem it's "sticking" but not really. Sim to solder to a battery and more might "stick" now then fails because of the metal or coating/plating of the parts.

If you can get Eutectic solder, common is 63% Tin and 37% Lead melts @ ~ 360°F, can work faster then other types. May wet better but big issue is when done they don't go "slushy" during cooling. This solves many "cold" joints because wires etc won't have time to move. ⚠ If you find old "Mil Spec" solder is possible is a Eutectic formula but be careful because those formulas can be Worse then Lead solders for your Health.

Low Temp Solder Paste maybe a Eutectic formula and also may meet RoHS too but not rated for potable water plumbing. While most made for Surface Mount Electronic parts, low temp solder "micro beads" mix with Flux is very easy to use elsewhere.

Contrary to common Myth... "Lead Free" Solders Are Not Safer for you when working on whatever. RoHS "Spec" is mainly for Finish Products during it's use and after so when end up in a Landfill etc doesn't "leak" so many HAZMATs. IOW if the Solder is "Lead Free," Soldering can often will try to kill you breathing in metal particles or Flux Fumes. Same for "Lead Free" solder for Plumbing required by current Code in most places. That's mainly to stop Lead Poisoning after when water, worse water with Chlorine, Chloramine, Florine, etc, push thru them.

[nickelplate759]

Pete...

I was always under the (possibly incorrect) impression that stranded wire is better for DCC than solid.  Is this really the case?  Or just an outdated line of thinking?

Jeff

I'm not an electrical engineer, but... it won't matter in the real world.

The main benefit of stranded wire is that it is more flexible.   This matters in applications where the wire needs to be able to move, including due to vibration (think transporting modules).

Arguments around signal integrity being better (or worse) with stranded wire don't apply at the frequencies we use.   Also note that ethernet cables use solid wire (usually between AWG 22 and AWG 26) and they run at much higher frequencies (250 MHz for 1 Gb over Cat 6) than DCC (about 8 kHz)

If you want a good get-your-popcorn moment, get two or more rabid audiophiles going about the merits of stranded vs. solid wire for loudpeakers.

<edited to correct ethernet speed to 1 gigabit (Gb), not gygabyte (GB)>

[MK]

If you want a good get-your-popcorn moment, get to rabid audiophiles going about the merits of stranded vs. solid wire for loudpeakers.

Would that be regular or oxygen free?   

[Maletrain]

For soldered drops, I much prefer solid conductor instead of stranded wire. 

The solid wire does now expand in diameter when the insulation is removed, so it looks smaller when soldered into the rail between the head and the foot.  And it is easier to shape the one solid strand so as to make it conform tightly to the foot and side of the rail. The drop wire comes out of a hole right next to the rail foot and goes up just high enough to go over the foot before bending into the side of the rail between the foot and the head, where it bends 90 degrees to go along the side of the rail. 

I start by scratch cleaning the side of the rail with one of those glass fiber "pencils".  I then get the wire shaped to fit tightly onto the rail.  I then put a drop of liquid flux on that spot on the rail. Then I use a small stick of wood to hold the tinned wire tightly against the rail.  Soldering is done with a brief touch with the tip of the just-cleaned iron tip that has a small amount of solder clinging to it. As soon as the solder flows to the side of the rail from the iron tip, I remove the iron from the rail, but continue to hold the wire in place with the wooden stick for a couple of seconds to make sure the solder is totally hard before there is any movement. 

The skill part is learning just how much solder to have on the iron tip in order to get a good joint without any excess solder.

[peteski]

For general wiring stranded wire is a better choice as it is more flexible, but for static short lengths of wire like track feeds, solid wire  is easier to deal with, and results in a neater (read: less visible) solder joint. Strands of a stranded wire can "fan out" when soldered, which results in a larger ugly solder joint will not be easy to hide. Trying to re-solder to fix it will often result in melted plastic ties and even more mess.

As for electrical properties, at DC or the frequencies used in DCC power there is no difference between solid and stranded wire. Also stranded wire of the same gauge as solid wire has very slightly higher resistance since its cross-section has less metal (there are tiny open voids between the solid round strands.

[JeffB]

For general wiring stranded wire is a better choice as it is more flexible, but for static short lengths of wire like track feeds, solid wire  is easier to deal with, and results in a neater (read: less visible) solder joint. Strands of a stranded wire can "fan out" when soldered, which results in a larger ugly solder joint will not be easy to hide. Trying to re-solder to fix it will often result in melted plastic ties and even more mess.

As for electrical properties, at DC or the frequencies used in DCC power there is no difference between solid and stranded wire. Also stranded wire of the same gauge as solid wire has very slightly higher resistance since its cross-section has less metal (there are tiny open voids between the solid round strands.

Thanks Pete and George...

Concerning solid wire being easier to hide...  I solder my feeders to the bottom of the rail, rather than the side of the rail or PC ties.  One of my biggest pet peeves is seeing a really well done model railroad with highly visible blobs of solder and feeder wire on the outsides of the rail.  Soldering your feeder wires to the bottom of the rail is a little bit more work, but it looks so much better!

Jeff

[robert3985]

If a cat etc can pull a joint off easily, is something wrong when you solder. Standard 60/40 lead solder will not do that unless the joint is "Cold" or have other problems making the solder to seem it's "sticking" but not really. Sim to solder to a battery and more might "stick" now then fails because of the metal or coating/plating of the parts.

I was making a JOKE about a cat pulling feeders off.  My last cat bit the dust about three years ago, and the layout room has been cat-free for at least a couple of decades...after Cally decided my scratch-built telegraph poles needed to be munched on.

My preferred solder for my 6" 24AWG solid copper feeders is 96/4 coreless silver-bearing solder...which is also what I use to solder my trackwork and also all of my brass & NS projects.

My preferred soldering instrument for attaching my flattened & tinned feeders to the bottom of both my Code55 and my Code40 rails is my American Beauty 250W resistance soldering station with the tweezer tool.  Since my track was already laid, this worked perfectly as it both holds the feeder to the bottom of the rail and applies heat very quickly, not melting my Rail Craft ties...and keeps holding after I step off of the pedal until the solder solidifies.

The only flux I need is Superior No.30 Supersafe Soldering Flux...self-neutralizing and I did not clean either my already laid rails nor my bare feeder ends...and I always got a perfect joint.  However, on my hand-laid turnouts and my cut-down super-short rail joiners, I clean where the solder joints will be, and scrub my PCB ties with a pencil eraser to get rid of oxidation before using them.

The six inch feeders get attached to my sub-buses with appropriate (red) genuine 3M Scotchlok "suitcase" connectors, and the sub-buses get attached to 12AWG fine-stranded, oxygen-free pure copper main buses in red/black zip-wire format, also with appropriate (brown) genuine 3M Scotchlok connectors. I prefer these over soldered joints when possible.

Cheerio!
Bob Gilmore