Cork roadbed is laid for my mainline loop and I’m loosely pinning my turnouts and flex track.
Haven’t started nailing the track yet because I need to find a drill bit tiny enough to drill through the ties (Atlas code 83 flex; holes are not drilled all the way through). But I already see an issue. Some of the track segments necessarily meet on the curves, and the last inch of rail does not want to conform to the arc, so I can tell that the joint here will want to have a slight kink.
This effect is amplified by the fact that I had to remove the end tie to be able to fit the rail joiner on, so the rails protrude a little bit, which means there is even less incentive for them to be curved right at the end.
Here’s a visual aid.
Obviously I’ll be cutting the inside (right) rail a bit to match the other, but you can see how it’s taking all these thumbtacks just to force the rails to even PRETEND to curve at the end, and there would still be a kink here if the next section was laid.
I did find this advice online…
To prevent a kink at the joint, join the next section while the joints are straight. Apply a small amount of solder flux to the rails and solder both together at the joint. Using flux and working quickly, you can solder the rail without melting ties.
…but I don’t know what flux is, and I cannot envision how this would help.
What are your tricks to maintaining the proper curve through these joints?
First, flux is a chemical cleaner that removes metal oxides when heat is applied. It is usually in a paste form but there are liquid forms as well.
The trick to eliminating the kinks is to join the ends of your flex track pieces together before laying them in the curve. Start laying the flex track in the curve, but leave the last 10" to 12" straight. Then solder on the next piece of flex track. Once the rails are soldered you can then lay them in the curve just like it was one continuous piece of flex track.
To solder the rail ends together, join the rails in a straight line with rail joiners. Then apply a small amount of flux to the rail joiner, and then heat the joint and apply solder quickly. If you are quick enough you won’t melt the ties. You don’t need a lot of solder. There shouldn’t be any blobs on the rail joiners or the rails.
One important point is that you must have the right flux! There are two kinds: rosin and acid. Never use acid flux on anything related to model railroading!! The acid continues to eat away at the joint long after the soldering is done, and eventually it will do a lot of damage.
A few other points:
Most solder for hobby work comes with the rosin already built into the core. However, it is usually beneficial to have some flux separate as well, especially if you are just starting out.
Smaller diameter solder is easier to control and melts faster. Stay away from solders intended for plumbing.
Learning to work quickly is the key to avoiding melting the ties. If you prepare the work properly, i.e. everything is clean, the solder should flow into the joint in just a few seconds. As soon as the solder flows into place, remove your iron.
For soldering rails you need a decent sized iron. It doesn’t have to be huge but a 15 watt iron intended for fine electronics won’t work.
You must keep the tip of the iron clean. I use a copper sponge like the ones intended fo
The advice you found is sound. I soldered all my curved joints while the flex track was straight (tangent) at the area of the joiner, then carefully aligned the remainder of the curve. As you note it is a multi-step process since you have to trim and dress both mating ends of the inside rail.
You’ll get the hang of it very quickly.
Flux is a chemical that cleans and aids in the flow of the solder. DO NOT get plumber’s acid flux but rosin flux for electronics and wiring. For track work I use Superior #135 paste and apply it with a toothpick. The initial heat from the iron will cause the flux to melt and flow all around the rail joiner, then as the solder melts it will flow and follow the flux.
There are liquid fluxes and some that are water cleanup and such. It helps to clean off the excess flux after the joint is cool with a cotton swab and soma alcohol.
From Wikipedia:
In soldering of metals, flux serves a threefold purpose: it removes any oxidized metal from the surfaces to be soldered, seals out air thus preventing further oxidation, and by facilitating amalgamation improves
In building my last two layouts, I would solder two track sections together (making sure the joints were staggered) and lay out the curve first, and then cut the ends to fit the adjacent tangent trackage. It worked like a charm.
I’ve done the same on my last 3 layouts, except I cut the rails so the joints were even/parallel (not staggered). It also worked like charm. I’ve found no compelling reason to stagger joints.
I have joined as many as 4 pieces of 36" flextrack together and soldered the rail joints on the work bench. If you don’t solder the rail joints while the flex track is straight, there is no way to avoid kinks which will cause derailments for sure.
Looks like you have some sound advice here about ironing out the kinks on your radiuses by soldering them prior to laying them down. Has been the solution as long as I can remember here.
Just an FYI for you as I’ve done several experiments on gluing down track after it’s laid with T pins. Exactly what I’m going to do when I ever get to that point as these experiments were quite successful.
The first experiment I diluted wood glue with water and applied the solution in-between the ties with an eyedropper and let it dry overnight. It worked very well as the solution seeps under the track ties as the water evaporates as it dries. The track was adequately secure but could be removed without damaging it with a putty knife. This works out well if you ever want to change your track routing plan sometime down the road.
As I thought about the interior wood glue solution that is water soluble even after it’s dry, it would later get soaked by ballasting. It occurred to me the track could possibly come loose on the radiuses where there is retention. I thought of using waterproof exterior wood glue but felt it would become too permanent on the track ties if ever removed. Once dry, that stuff doesn’t like to come off of anything. I never tried that experiment though because I didn’t have any. It may favor the cork and be the ‘Cat’s Meow’ for all I know.
I did a final experiment with Alex Plus diluted with water and it worked just as well. Alex is water soluble when wet but becomes waterproof after it is dry. After it set overnight the track could be removed and the caulk was left stuck to the cork as the track came up clean. Alex sticks to both surfaces being fastened together but favors the more porous surface to adhere to when pried apart.
A couple of additional points I may have missed above:
It is not essential to have the joints directly across from each other, as both will be part of a rail unit once soldered and each rail will curve nicely.
If ties are close to where you will be soldering and there is concern about tie melting, use heat sinks on the rails next to the joint soldering point. I used two alligator clips, one on each rail. That minimizes the heat seen by the next ties.
It sounds like you have not soldered much yet. If that’s true, before you solder some of your track, try practicing on some scrap ends of track you may have. Ruin the scrap while you learn so you don’t have to use bad words ruining some good pieces of flex track.
Something that hasn’t been mentioned yet, is to let your soldering iron get very hot before you touch it to the rail. That way you can be on and off the joint very quickly.
One trick I do is to wet 2 pieces of paper towel and put them on either side of the joint. When you hear them sizzle you have probably gotten the joint sufficiently hot enough to solder.
As mentioned practice before you do it for real. Also, use the solder sparingly, then there is no to very little cleanup of solder blobs.
As an aside, and not intended as a “rabbit trail”…
The current issue of MR has an article about Resistance soldering irons. It was an eye opener for me, and if I was starting a new layout, I would definitely have to have one.
You’ll need to clean up the cut ends of each rail with a needle file both to slide the cut piece of four ties off the flex track ends and slide on these finishing ends.
Also, drilling the same size tiny track nail holes into the tie end just outside of the rail will allow you to insert a model spike rather than a track nail which will hold the curve better than a track nail in the center of the tie.
3/64" bit gives a clearance hole for track nails or spikes. I use a model maker’s hand drill or a pin vice with spring loaded helical drive to drill these holes. The plastic is hard but thin so starting the hole accurately is the main challenge. The drill bites through quite quickly. You don’t want the clearance hole to enter the roadbed!
You’ll find you need more tie holes than Atlas provides.
Atlas flex track is very springy and wants to return to straight. Try adding a piece of sectional track with joiners to the cut end in order to apply the necessary force to complete the curve at the end. Then remove the sectional track to continue laying.
I find that Atlas “universal” Code 100/83 joiners just aren’t. I need to squeeze every single joiner in order to get a firm sliding fit onto the Code 83 rail end. Every darned joiner. And it’s really easy to squeeze too far. Best tool I’ve discovered so far is a pair of flat face snub nosed model pliers by Zona (apparently no longer made). Squeeze from one side and then the other so as to allow for the fact that plier jaws aren’t parallel. Squeeze only the center portion of the joiner in order to keep the ends open for ease of fitment.
Wow. Just… wow. So much vital info here. I’m feeling like I need to take out a student loan and go back to college as a Model Railroading major with minors in Physics, Electrical Engineering and Not Getting Discouraged.
Thanks fellas. I’ll have to read this thread over several more times. I don’t have an “iron” yet, so thanks for the tips about that too.
Here’s the embarrassing part: I don’t remember soldering rail joints as a kid and we had a lot of joints because our first layout was all sectional track. I do remember soldering little wires to the rails, and I learned not to solder over my head by having solder drip onto my hand (luckily not into my eyes) while working underneath the train table.
But in general I thought that the rail joiners were conductive, so the newest question bubbling up into my head is… are we soldering the joint because ALL joints need to be soldered, or are we soldering the joint in this case only because it will help retain the curve?
Again, I am grateful for all this help. I’ve had good results from listening to you guys so far, right through to laying cork for turnouts.
Unless they’re insulated (plastic), yes, the rail joiners are conductive. However, over time, their surface can oxidize enough that they’re either less conductive or not conductive at all. I solder all of my rail joints (except those where there are bridges, as I build the bridges so that they’re removeable - handy when the “water” under the bridges needs to be cleaned vacuumed or dusted).
As others have mentioned, if you do the soldering before the curve is completed, the soldered-together track will bend just as well as the portion that’s already curved.
We’ve had numerous threads on this subject over the years, full of useful information. It only seems like a firehose because you’re getting all the options at once. Take notes and quietly plan what of the advice given you want to use – then do that.
I second the resistance-soldering idea for this use: this gets around most of the concerns with tie-melting or time to avoid cold joints and such. Use a good no-clean flux and, ideally, one of the eutectic solders (which “harden” quickly to form the joint) – and yes, this is a perfect excuse to solder a small feeder wire into the joint while making it.
As an introduction to the wide world of soldering, read some of the material here as you have time:
There are other specialty soldering sites, including those catering to the jewelry industry, that are useful resources in ‘learning at low cost’.
If you want, you can pre-bend the ends of the joint slightly using a curve gauge, while the track pieces are still straight and otherwise ‘uncurved’, before applying the joiner so there isn’t a short ‘hard spot’ in your curve. This may be overkill to most modelers, though.
A general rule, if you’re planning to keep expansion joints in trackwork, is to solder your curve and transition joints religiously and leave the open joints in straights and at turnouts. We’ve had threads on that too.
Welp, it looks like I’m dead in the water (or maybe dead in the canyon) until I have acquired ye Ancient Art (and Tools) of Soldering Magick. I’ve been researching today and there’s no way I can justify the cost of a resistance solderer, nice as that would be. So I’m considering two other options; 1) buying the “good enough for a beginner” X-Tronic #3020-XTS-ST (link) online and weeding my garden while I wait for it to arrive or 2) running out and getting a 60-watt wand for couple of sawbucks (and some flux and solder for few fins more) so I can get started practicing my soldering wizardry tomorrow.
Thoughts on which route to take? Really, I can’t afford half a house payment for soldering equipment, so the resistance stati
Wait a sec. What do you mean by “late”? Did something happen to Randy? He was among the first people to respond to my first posts and welcome me aboard.
You don’t have to start the whole piece of track where the last one stops, if that’s going to leave you with a bad kink. Use shorter pieces that start and finish on straights and avoid joints on curves.
But yeah, you will have to learn to solder sooner or later. Sooner is better.
