Okay, admittedly this issue can be like discussing politics or religion or possibly the Chevy vs Ford vs Mopar debates back in the 50's and 60's. But it is probably more entertaining that some of the other controversial discussions going on these days. Personally, I don't favor soldering rail joiners. I like to allow a gap of .015 inches between Flex track sections and other track work such as switches. I prefer to have at least one drop feeder for every piece of track no matter what its length is. That gap is for thermal expansion of the rail due to temperature change. That is sufficient for a temperature change of about 100F degrees. Some like to solder all the joints while others only solder the joints on curves. On curves the danger is from both thermal expansion as well as contraction. I don't worry about humidity affecting the benchwork. Wood will expand a lot more across the grain that along the grain. A good primer/sealer followed by a coat of latex paint will prevent any problems there. So, what is your preference, solder or no solder and maybe tell us why?
I've been soldering mine but only have maybe a 7 degree temperature swing in the shop where the layout is (68-75). So far no problems and some of the track has been down over a year. Sumner
I have to wide of temperature swings to even consider anything more than a few feet. I make sure the joiners are snug, and apply a liberal coat of molylube to help conductivity.
It depends upon the individual situation. Someone learning to lay track and not the best joints; or a well experienced person with a higher quality outcome. Controlled environment, where you do not have much chance of expansion, contraction, or humidity causing corrosion at a joint. Versus a garage, outbuilding, or?
The type of track and rail joiners you use also makes a big difference, in powering the track. Kato Unitrack "Unijoiners" surround and support the metal rail joiners in two layers of plastic (a plastic housing that is then held inside a pocket in the plastic roadbed. There are some Unitrack users that solder every Unijoiner to the rails, some that solder none. Track power is fed through the powered Unijoiners (with wires soldered to the bottom of the metal rail joiner inside the Unijoiner,) yet some still solder feeder wires directly to the rails. The bigger question for Unitrack users is "How how many unpowered Unijoiners between powered Unijoiners?" Because 'how far" is typically measured in number of sections of Unitrack, rather than linear feet/inches.
I solder every other joint so one feeder electrifies 2 track pieces. Then I leave the standard gap on both ends. Rinse, lather, repeat....
I use a silver-containing epoxy. Ensures electrical conductivity, challenges neither my limited soldering skills nor the melting temperature of plastic rail ties. Is fairly low-strength, so I can pull joints apart if need be. Tarnishes in a few months to color of “nickel silver” or brass rails. Does require filing, which is easy due to its low strength. Never has clogged any of my files. My layout is under construction, inner loop is approximately twenty feet long with precisely one feeder hooked up for temp power. (Out of four total feeders sunk through the table) Makes me question the need for the other feeders, but wire them up anyway, I will.
When I used Atlas code 80 flex, I soldered every other joint. I now use Kato track and have a feeder about every four feet. Don
I haven't ruled out soldering down the road, but currently no. When I laid my track, I put in feeders every other piece of flex.....when I got ready to power up, I couldn't wait, and had to try running a train when I hooked up the first feeder to the buss.......so one feeder powering 200ft of track. Its a big loop, so it's only 100' in each direction from the feeder, but the train ran perfectly and I couldn't detect any slowing at the farthest point from power. Soldering wouldn't have improved on that...........I figure if I start to have any issues down the road, I'll address them as they pop up, which may involve soldering.
Don’t mind at all. It’s: MG Chemicals 8331D Silver conductive epoxy. 20-minute working time. I found that enough time to make up two joints, three if it’s straight track, or if you’ve got your inside & outside rails clipped to length & filed smooth. So, mix up small batches. But now for the part that hurts: $97.30 on Amazon. Bought mine in late 2021 for~$60.00. I’m still using what I bought then; it’s hard to tell how much is left because the stuff is so opaque that you can’t see the heads of the plungers in the syringes.
Pretty much everything on my flex track layout is soldered except the duckunder bridge and at the ends of a very long straight viaduct. But the room has fairly constant temp and humidity. Couple of comments on things mentioned above: Soldering curved tracks is the best way to avoid kinks at the joints, but as far as expansion and contraction go curves are not as problematic as straights. Curves can slightly increase or decrease radius under the stress caused by length changes while straights have nowhere to go. From what I've seen the expansion and contraction of the benchwork due to humidity changes is much more of an issue than expansion and contraction of metal rails due to temperature changes.
Ok, that’s it…I’m takin’ apart all my table and benchwork…white pine, plywood, OSB - ever’thang, and I’m gonna soak it all in PEG-1000 for six months and let it dry and then put it all back together. Ain’t gonna let no more moisture back into NUTHIN’!!!!! Ok, a bit silly, but it would work. (Hmm, wonder if my foam board will stand up to PEG-1000, too?)
Now this idea intrigues me - do you use a dry moly powder, or are you using it in a grease form? I’m thinking of putting moly powder in some 99% isopropyl alcohol, then put that in one of those squeeze bottles with a needle-tip cap, then squirt a bit of that in at the joints. Would dry out quick. This has to be a product already, right?
All those nasty chemicals. Yuk!! We should go to formed and reinforced concrete. No dangerous chemicals, warped and unstable wood which deletes the forest. Etc., etc., etc.. Anybody up to it? I was thinking of using plastic stackable shelving with foam boards and a facia to hold controls. I have a big selection. Then I would have lower shelves for storage.
My layout is 99% Unitrack with a couple of sections of flex track where Unitrack just didn’t work. I have soldered some of the joiners in areas where there were height differences in the rails, which happens sometimes with Unitrack. The majority remain unsoldered without any conductivity issues. I do have feeders averaging about 2 feet apart over the entire layout. If I were to do it again, I’d use code 55 rail joiners in place of the Unitrack ones, they fit snug and eliminate any rail height issues between sections. Much more work, but worth it if the track is permanent.
Let me add to your last sentence above: AS LONG AS "...the room has fairly constant temp and humidity." One good power outage could change that situation. On the contrary, curves are very susceptible to contraction, more so than straights. Those little plastic numbs will not hold the rail in place Humidity changes are easily solved by a good a good application of a primer/sealer and possibly an application of a white latex paint. The paint doesn't have to be white but white will make it easier to do any work under the layout. Then all you need to worry about is thermal expansion of the rail. The prototypes have the same problem with welded rail. They try to force the expansion vertically rather than horizontally. But it doesn't always work and "sun kinks" develop. See below:
