There is good conversation on soldering rail joints in a layout.
Most recommend leaving some joints unsoldered to allow for expansion due to heat/cold changes.
What is the recommended number of joints unsoldered or how often. I am assumig the unsoldered joints should be on straight runs and not on curves.
Can rails be soldered when they are already glued in place?
Yes, except on curves I solder my joints after placement. Makes everything a lot easier.
Magnus
At the club, we solder every other rail joint on our flex track. This allows for expansion. We also solder small sections to the longer 36" sections. We then solder a feeder to each remaining rail(usually about 72" of rail). The track is glued to cork roadbed(which is glued to 2" foam). We have had no expansion issues so far.
My home layout has only a few soldered joints(on flex track curves). Again, there is a feeder soldered to each rail. My flex track is spiked to Homabed, which is glued to 1/2" plywood.
Jim
I solder two 3’ sections of flex track with a 18ga jumper wire, resulting in a continous 6’ section of track. Between the 6’ sections I just use rail joiners to provide for some movement in the rails. With this set up, my locomotives are never more than 3’ from a jumper wire.
I use cork roadbed glued to a plywood subroadbed with yellow glue. I attach the flex track to the cork roadbed with latex caulk.
A pictures worth a thousand words…
USE EXPANSION JOINTS!
Hi John,
I solder every rail joint in curves, and I do it before bending the rail so the joints can’t kink. I leave every straight rail joint unsoldered, and use the edge of my NMRA gauge to make sure there’s space between the ends of the rails.
But when you talk about rail joints, there’s another point I think is important. I never depend on rail joiners to carry current. I solder a feeder wire to every length of rail, and connect all the feeders to heavy-gauge bus wires under the plywood subgrade.
So long,
Andy
This photo shows a soldered rail joint. A small amount of non-acid paste flux was brushed into the rail joiner just before the track pieces were joined. When the pieces were properly set a hot soldering iron was applied to the joint and solder applied. The solder followed the flux into the joiner, effectively welding the joint together. If it’s done properly, the soldered area should be nearly invisible, as this one is (circled in red). This is a typical soldered joint on my layout. I have insulating gaps about every six feet (the layout was originally set up for DC block operation). These gaps also serve as expansion gaps.
Expansion and contraction happens when the trackwork is sublected to extreme temperature changes. Humidity changes will cause the wood benchwork to expand and contract. If your layout is in a climate controlled environment, your problems should be minimized, right? I’ve soldered all my joints on my 4x8 layout, and left the turnouts un-soldered for ease of replacement. A 4x8 doesn’t have a lot of track, but I’ve never had a problem with my alignments.
So, it depends where the layout is (environment changes), and the size of the layout. Solder a feeder to every piece of rail and every frog, even if it’s joints are soldered (no guarantee every joint will be solid forever).
From a “mrhedley”, who posted this on modelrailroadforums in December last:
The Mark’s standard handbook for Mechanical Engineers lists the coefficient of Thermal Expansion for Nickel Silvers as 9.5 x 10 -6 inch/inch per degree F. For a thirty degree difference between the temperature at installation, that is approximately 1/4" in 100’.
I think we should be able to dispense with any worries about temperature causing problems with nickel silver track unless it is monolithic and at least 50" in length, and held down quite well with nothing but track nails. For sections 3-6’ long, our problem will rest entirely with benchwork changes, and if wood, due to humidity or structural integrity.
And it always amazes me the tiny amount of expansion that will cause a kink of that size. I repaired one where I trimmed no more than 1/32" of an inch to make it go smooth again. Tiny expansion - huge kink.
You should have seen the kink I got on my layout after Rita ripped off part of my roof, the part right over the layout, naturally. It made that little kink look like nothing. It was several weeks before the electricity was restored but after I got the place cooled off (it was really hot here that year) and got the layout dried out the kink went away.