soldering track


brubakes

Member
I've never soldered my track before (this going back to when I was a kid) and now that I am going to start a "real" model railroad I know its a must. However, I'm looking at my flex track now and the rail joiners I have installed while I start playing with my test test and I see no room for solder to fit in the rails. Is there a special rail joiner for this or is this again one of those simple things I'm making way overly complicated.
 
Id like to see what others with more knowledge have to say about soldering the track. I have been wondering about that myself.
 
Some of the others can probably give a good rule of thumb on how often to solder the joints. I soldered all and then had to cut expansion gaps to allow for the effects of temp/humidity. I have expansion joints on the "dog bone" ends and in the long runs of track- both mainline and long sidings. Either jumper across the expansion or drop wires on both sides to connect to the track buss.
Regards,
Jon
http://www.dollhousedesigns.com/ModelRR/ModelRR.html
 
Soldering track can become a psuedo-religious argument, like N-scale versus HO, etc.

Anyway, I only solder long flextrack curves. Other people insist on soldering almost all joints.

Put a heatsink (mini alligator clips work well) on each side of the rail joint to avoid melting the plastic ties. Apply flux to the joiner, put your iron near the joint and touch the solder to the heated joint. The solder should flow smoothly into the joint / joiner. Remove the iron.

Like anything else, you get better with practice and some people don't bother with flux.
 
perhaps not the best way but i decided to solder track without the joiners and like the result on the few that i did. left 0.5-1mm gap between the rails, held them level, heated with the iron and filled the gap with solder. filed the blub of solder flat with the track and on sides, now the joints are seamless, not a slight wheel clack just how i wanted . i intend to fill the isolated joints with plastic pieces (ala isolating the frog of old shinohara turnout) so they are not clacking as well. i intend to solder everything.

as for expansion, perhaps i'm in for surprise but i just don't see it as that important on small layout.. will see, its in single digits outside so today the garage is the coldest it will ever get.
 
There are things to keep in mind:

1) use a good iron (I like the Weller ones)
2) keep your tip tinned and clean (a clean and tinned soldering iron tip is more efficient in heat transfer)
3) use heat sinks (those black and silver paper clips work nice)
4) get some flux (helps the solder flow into the joint)
5) use rosin core solder only (acid core is very bad for electricity)
6) get the track as straight and level as possible
7) wear eye protection
8) all it takes is a little solder
9) clean your soldered joints well after the joint has cooled (remove the flux residue, especially from the rail heads, so that it won't hurt electrical conductivity).
10) let the solder melt into the joint, instead of using the soldering iron to melt the solder directly.

I experimented, and what I found is that I would heat the joint a little, then get the solder out, and when the solder began to flow onto the rails, I'd remove heat, add some flux, and then heat the joint again until the flux had the solder flow into the rail joiners. If the solder was resistant to flow, I would add more flux, and more heat. With some practice, I can sometimes get it done without using heat sinks, but sometimes not. I've got a few curled up ties that will be replaced, which you usually have a spare or two because of cutting the track.
 
I've just started laying track. I take 2 peices, cut back 2 ties on each end. I then slide a rail joiner on, flip both pieces over and solder the rail joints underneath the track so you dont see any soldering at all. So far its worked just fine.
 
There are things to keep in mind:

1) use a good iron (I like the Weller ones)
2) keep your tip tinned and clean (a clean and tinned soldering iron tip is more efficient in heat transfer)
3) use heat sinks (those black and silver paper clips work nice)
4) get some flux (helps the solder flow into the joint)
5) use rosin core solder only (acid core is very bad for electricity)
6) get the track as straight and level as possible
7) wear eye protection
8) all it takes is a little solder
9) clean your soldered joints well after the joint has cooled (remove the flux residue, especially from the rail heads, so that it won't hurt electrical conductivity).
10) let the solder melt into the joint, instead of using the soldering iron to melt the solder directly.

Excellent list! The only one that I do differently is #10.

I just did a clinic for the District NMRA Meet in my area last Saturday. The subject of the presentation just happened to be Basic Reliable Soldering for the Modeler. I learned the technique I use from the professional electronics repairman. He learned it from his Father who ran a TV repair shop for many years. His Father learned it in the Service.

In addition to using extra rosin flux (I use the liquid from MicroMark), I put a drop of solder on the iron. This allows a much faster transfer of heat into the joint when the iron is placed on the joint. Most times I don't need to add any solder besides what is on the iron. The solder will flow almost immediately into the joint. When it flows remove the iron. You are done. You will have a good, solid, reliable joint, and you will not melt ties. The idea is to heat the area as fast as possible and get out before you have more heat than needed to make the joint. The molten solder on the tip of the iron makes that possible. The time is about 1 second from the time you touch the iron to the work and when it is finished. You do not need a large iron to do that either. I use a 25w standard iron for almost all my work. (I have close to 5,000 solder joints on my layout done this way and I have never had a failure.) A good solder joint will be smooth and somewhat shiny in appearance. Oh, and heat sinks are not necessary with this technique.

Here is the rail joint I did last Saturday. Notice that the only damage at all is a slight softening of the "rail spike" directly below the joint. Took less the one second.

Soldering1w.png


From the top:

Soldering2w.png


BTW, in my "audience" last Saturday were 2 MMRs and a retired Electrical Engineer from Kodak. One of the MMRs is a retired Telephone Co. employee with many years of soldering experience, and the other is a retired mechanical engineer. All said the technique is excellent and is how they do this type of soldering.

Practice, practice, practice!
 
How do I know where and how much space to leave for expansion. I never even thought of that until I read it here.
 
I leave every other 3' section of flex unsoldered with about 1/16" space. You really don't have to have (nor want)a large gap. I drop feeders as I showed above to each 6' section of flex that has been soldered. BTW I also only solder one end of turnouts for ease of removal if needed. Most of the expansion and contraction that causes problems is caused by change in humidity rather than temperature change. I try to keep as small a range in humidity change as I can in the layout rooms. That means humidifier in Winter, and dehumidifier in Summer....
 
Ray, that sounds cool (adding solder to the iron) but I have not been able have success with that technique. Many times the solder sticks to the iron tip instead of the track. I find such especially when using a fine solder tip for doing hardwiring in my locomotives.
 
Ray,
I've had the same problem as Trey when I tried to solder my joints as well. Is this a problem with the tip not being clean or something else?
Dave
 
Ray,
I've had the same problem as Trey when I tried to solder my joints as well. Is this a problem with the tip not being clean or something else?
Dave

I have not had that problem at all. Are you using a separate rosin flux? You want to get the hot tip of the iron firmly on the materials to be joined. The solder flows into the joint making a solid solder connection. You will see the solder flowing. The tip of the iron should be well tinned before you start, and hot! Also the work being soldered needs to be clean. I use a small metal brush to clean the rail prior to soldering.

People will tell you the technique will increase the chance of having a "cold solder". Funny thing is as soon as I learned this technique, I stopped getting any cold solder joints....... My guess is that you are not getting the tip (and the molten solder) firmly on the work you are soldering. If the molten solder doesn't touch the joint, it will stay on the tip of the iron.
 
Ray, that sounds cool (adding solder to the iron) but I have not been able have success with that technique. Many times the solder sticks to the iron tip instead of the track. I find such especially when using a fine solder tip for doing hardwiring in my locomotives.

Trey, if you are soldering little fine wires to other little fine wires, the technique doesn't work very well.... For that, I would put a drop of rosin on the twisted wires, then use a well tinned iron under the wires (heat rises.....;)), and then add a bit of solder from above. I use different techniques for different circumstances. You may also be using too much solder on the iron, it doesn't take much. For the track, you may not be getting the molten solder in contact with the joint. You will see it flow into the connection.

The one I explained before works very well soldering to PC board, the lugs on toggle switches, spade lugs (I crimp and then solder), and for rail connectors and drop feeders. I would not recommend it for putting metal models together that require soldering, and certain other applications.

If I have time I will see about putting up a video of the technique. (I had the camera recording in order to be able to project what I was doing on a white wall in the room we did the clinics in.)

[edit] For any of you who might be interested, here are a couple clips from the clinic I did on the subject last Saturday. The first one shows me soldering wires into a spade lug. The second is soldering a feeder to the rail.

th_SolderingTech1.png


th_SolderingTech2.png
 
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Thanks for all the help so far guys. I think I have the process down for premade straight and curve track. I'm actually amazed at how much of a difference soldering the track makes. I'm sold on the idea now.

Now I have to work with flex track. Do you just make your curve and cut off the "extra" track then connect the next piece? What is the best tool for cutting the rail?
 
Spend the money and get a rail nipper especially made for the purpose. Some people use Dremel tool cut off wheels but I find a nipper like the Xuron rail nipper to be a good compromise between price and performance.
 
My battery powered Dremel died so I've been using the Xuron nippers. I still have to dress the cut a bit with a needle file but not as much as when hacking through the rail with a razor saw.
 



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