Question about flex track and track connectors

[Frisco's_Iantha_Branch]

To further explain my setup. I have a bare 4x8 sheet of ply wood for a base. I don't use road bed to cut cost. It works just fine for me. After I have the track how I want it I come back with white glue. Yes, white school glue. It's cheap and it works just fine. It holds a curve in place, but allows track to come up easily with out breaking the ties apart.

 

[Selector]

Okay, pay attention...

We mostly build on wood of some kind...ply or milled.

Wood absorbs moisture, and when it does, it increases linearly, but mostly transverse to the grain. It swells across its width typically.

If you solder every rail to the one next to it via joiners, and fix the rail elements solidly to the wood, what will happen when the wood under the tracks swells? It'll do weird things, to be sure, probably straighten some curves.

Now, the season passes, and the space dries a fair bit. The wood dries, and shrinks. Above it, any solid rails will want to compress as the wood grains below it come closer together due to shrinkage. Your rails will have to give someplace to the compressive forces, and what happens typically is that they'll deflect to one side, but they are known to buckle upward. So much for tracks following your centreline.

So, there are two things about track...keeping them put and aligned, and keeping electrons flowing continuously through them.

If you solder every other joiner and leave the two on either side of it to slide freely, you will accomplish 90% of the problems encountered with the two processes above...continuity and alignment. You can solder feeders to every rail length, no matter how long and where it is joined...or ends itself...or you can solder two lengths at the joiner, and add the feeder there. Two lengths, one joiner with added feeder = as much as 6' of continuity and solid rail that will stay aligned. At each end of this 6' length of solid rail, with power, are a single sliding joiner whose dual purpose is to provide the usual desired alignment, but it also allows the rail system to contract and expand as the wood below it does the same thing.

It boils down to allowing some joins the freedom to compress and expand, and soldering many of them for the purposes of continuity between them and rigidity, particularly at curves.

-Crandell

 

[tankist]

Crandell, correct about wood properties but lots can be done to minimize the effect.

but when wood is engineered ie chipboard those fluctuations are minimized. ordinary plywood can be sealed with polyurethane to dimnish this effect as well. then on top that surface of engineered wood, lays surface of insulation that changes very little (if at all), elastically glued so to float with any change. then on top of that lays cork roadbed which is flexible and is glued, more or less elastic adhesive caulk. i think there is plenty of buffer to compensate for any issues with the base. garage went all the way down below freezing this winter and as humid as it gets in summer. apart of plastic insulating joiners between detection sections, everything else is soldered with no gaps and polished to be "continuous weld " rail - i don't lilke clickety clack much. so far - all good.
but i do have smaller layout then you guys, so...

 

[Selector]

Anton, I believe the guys who experience all the kinking are the ones who use nails and screws to keep their rails in place, often without any roadbed at all.

I agree that moisture-proofing wood should alleviate about 95% of the unwanted changes and their resultant (unwanted) effects. I also agree that using acrylic caulk, for example, between the tracks and roadbed should pretty much reduce the squirrelies to zero. I have only MDF non-sealed spline roadbed and a thin layer of caulk between the ties and the splines. I also ballast my tracks, of course....so between all those things, I just don't get track movment. The only difference I see, and have had to make allowances for, is where my diagonal swing-up bridge meets the yard module. It is hinges on the module across the operating pit, runs diagonally for about 4', and then is held in place via two barrel locks. When the vertical 1X4 swells with moisture it swells transversely, with the effect of making the receiver for the barrel lock further away from the tracks above it. I do end up with about a 1/16" height difference before I begin to run the dehumidifier.

-Crandell

 

[tankist]

and thats why frisco's setup puzzles me a bit (to say the least). i don't think i can recommend anything like this. besides potential warping of wood down the road, running track on framed plywood is like runnig it on a guitar - resonates like crazy. after half an hour of running, headache is guaranteed. tried gluing the track with white glue. seemed to become even noisier and snapped in a pinch when i tested how strong it was held down.

frisco, try installing roadbed. the difference to the ears will be like - aaaahhhh

 

[jeffrey-wimberly]

Jeffey, even with the gap, if you soldered both rails to joiner it is still rigid connection. how is that helps with any expansion contraction?

The longest block is only 7 feet. I was referring to expansion/contraction of the rails. The gap between the blocks (no joiners) leaves space for the rail ends to expand into without warping. Contraction isn't really an issue as to environment is controlled for the most part.

 

[Frisco's_Iantha_Branch]

Well, I haven't had a problem with it breaking. How much white glue did you use? Did it dry all the way? I normally put a bead of it under the track, then a drop on the sides of the ties every about 4" alternating sides.

 

[Necrosaro420]

I just purchased a 5/8th 4x8 sheet of plywood, hopefully that will work as a good base =) I plan on going around the edges on the bottom with 2x4 to make a base for it

 

[Frisco's_Iantha_Branch]

I just purchased a 5/8th 4x8 sheet of plywood, hopefully that will work as a good base

Yes it will, that's what I have.

 

[Necrosaro420]

Okay, pay attention...

We mostly build on wood of some kind...ply or milled.

Wood absorbs moisture, and when it does, it increases linearly, but mostly transverse to the grain. It swells across its width typically.

If you solder every rail to the one next to it via joiners, and fix the rail elements solidly to the wood, what will happen when the wood under the tracks swells? It'll do weird things, to be sure, probably straighten some curves.

Now, the season passes, and the space dries a fair bit. The wood dries, and shrinks. Above it, any solid rails will want to compress as the wood grains below it come closer together due to shrinkage. Your rails will have to give someplace to the compressive forces, and what happens typically is that they'll deflect to one side, but they are known to buckle upward. So much for tracks following your centreline.

So, there are two things about track...keeping them put and aligned, and keeping electrons flowing continuously through them.

If you solder every other joiner and leave the two on either side of it to slide freely, you will accomplish 90% of the problems encountered with the two processes above...continuity and alignment. You can solder feeders to every rail length, no matter how long and where it is joined...or ends itself...or you can solder two lengths at the joiner, and add the feeder there. Two lengths, one joiner with added feeder = as much as 6' of continuity and solid rail that will stay aligned. At each end of this 6' length of solid rail, with power, are a single sliding joiner whose dual purpose is to provide the usual desired alignment, but it also allows the rail system to contract and expand as the wood below it does the same thing.

It boils down to allowing some joins the freedom to compress and expand, and soldering many of them for the purposes of continuity between them and rigidity, particularly at curves.

-Crandell

Thanks, when you say every other joint, like just say on the left side of the track, you would solder one then skip soldering one, then solder another and so on, or do you mean like you wouldnt solder a left and right side, then on the next piece you would solder both left and right side, then next you wouldnt solder left and right and so on? Just want to make sure im understanding you correctly. Thanks!