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First attempts at soldering joints in flex track -- naturally, questions arise

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  • Member since
    February 2015
  • From: Ludington, MI
  • 1,862 posts
Posted by Water Level Route on Sunday, May 23, 2021 4:50 PM

Funny how I misread 7j43k's post.

My technique: Start at a fixed point like a turnout, build through to the next fixed point, ideally having the last piece laid being straight.  Avoid trying to make the final connection in a curve.

Mike

  • Member since
    May 2004
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Posted by 7j43k on Sunday, May 23, 2021 6:51 PM

Lastspikemike

 

The difference comes when you slide the rail ends into the joiners. Then making the last joint inside a curve is way easier thsn trying to "drop in" a straight of exactly the length of the gap. 

 

Well, Mike, it WOULD be if you have the rails cut to exactly the right length.  That's kinda difficult on a curve for some of us.  If you're joining two straights, they're already laid.  Just measure the gap, and cut the track.  Once.  No checking to see if it's right.  You MEASURED it.

Straight tracks do not just drop in. The joiners always make the piece of track longer than the available space. Sure you can slide the joiners all the way onto one rail but I fail to see how that's easier than just sliding the curved tracks together. 

Oh, it ISN'T.  What is easier is that you can get an accurate cut length between two straights that are already installed.  Can you do that in a curve?

And, Mike, you are correct that you have to slide the joiners out of the way to fit the track.  Is that scary?  Or really difficult?  Be reminded that you're going to have to add some filler ties around the joint anyway, so there should be no ties obstructing the "slide".

 

Heck it's even easier to join a curve to the end of a straight as your last joint. If you can get both ends inside a curve then the last piece of track to be joined up pretty much does "drop in". 

 

Yes, Mike.  If you enjoy fitting the curve together several times so that you get the final cut right, it's even fun.  Or, if accuracy in trackwork just isn't your style, you can do it just once and move on to other fun things.

 

Ed

  • Member since
    January 2004
  • From: Canada, eh?
  • 13,375 posts
Posted by doctorwayne on Sunday, May 23, 2021 11:53 PM

richhotrain

7j43k

In my experience, it's much better to lay the switches first, the curves next, and fill in finally with straight.

More power to those who can lay track in that sequence.

When I start a "curve", and I am speaking of at least a 90 degree curve (a quarter circle, if you will), I begin one end of the curve by connecting it to the last section of straight track previously laid.

Then, I form the curve, including easements, and then I connect the completed curve to the first section of straight track adjacent to the end of the curve.

If that first section of straight track adjacent to the end of the curve is a turnout, I obviously know at that point exactly where to place it. How could I know that beforehand?

Rich

On my layout, I did all of the curves first, soldering together as many lengths of track as were needed for each curve, then formed them to match the pencilled centreline - some were 90º or less and some were over 180º.  As each came near to where it would connect with a turnout or with straight track, I let it form its own easements, from the curve into straight track, cutting it off where it seemed most suitable.
I usually also solder with the iron inside the gauge, rather than outside.  If I were using a larger soldering iron, though (I have ones from 25watts up to one that's 200watt), I used it on top of the rail - it heats the rail very quickly and draws the solder into the joiner on both sides
The only unsoldered joiners are at the ends of my bridges, all of which are removeable.  If the unsoldered joiners fail to conduct power, I have wire drops on both ends of all bridge rails and on the connecting rails, and all that's needed is to clip them together (beneath the layout), leaving the bridges still removeable.

I never worried about whether the moveable rail (Atlas code 83 flex) was on the inside or the outside of the curves...simply cut it where needed and carried on.

I've melted lots of ties in my time, too, but it's easy to make replacements:  since my layout is around the room, the far side of the rails is generally unseen (although I do take some photos with the camera on-layout, and facing the aisle).

I simply trim the overhanging head of the plastic spikes that will be on that unseen side of the track, then use a triangular needle file to create a groove where the rail joiners will be seated.
I then use a small screwdriver or putty knife to lift the soldered-together track, and then slide the altered tie(s) into place - no bump at the rail joints, and not much notice of the rail joiners once the ties are in place and the rails have been painted.

I think that most of us have our own methods, developed over time and through experience, but it's also useful to read what others do, as there may be a step that could be added or another that could be skipped. 

I don't have a great deal more track to be laid, as most of it will be for industries on the upper portion of the layout...perhaps a fair amount of it will be street running.

Wayne

  • Member since
    February 2021
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Posted by crossthedog on Monday, May 24, 2021 1:09 AM

I've done about half the mainline loop now. I started at one turnout and soldered two tracks to it for the wall-side curve. With some experimentation I've learned that for me, the best method is to use lots of flux into and around the rail joiner on both inside and outside, then heat the inside of the rail joiner until the flux everywhere sizzles and liquifies and goes clear. This happens fast because I heat the iron up hot. As soon as I get the sizzle, I touch solder to the OUTside of the rail right above the joiner. The solder instantly flows throughout. I quickly drag the solder along the joiner to cover it all. If I do it quickly enough the ties don't melt. Heating the inside of the rail or joiner draws the solder through to the inside but doesn't create a big burl of solder in there. One or two of you suggested that this was the actual correct method, according to the science of how solder moves. I have found it works pretty well if I remember two things: Hot. Quick.

I've also found that in situations where I start at a turnout (i.e. all of my situations) it doesn't work to solder more than two flex track lengths together at a time while straight. If I do, then when I bend them around the curve, the joint on the loose inside rail travels forward away from the joint on the outside rail, which requires cutting off more ties so the track will bend, and the distance is compounded with each added length of flex track. It does this because both rail ends are fixed to the turnout rails at the starting end, so the differential (as it were) can only move in one direction. Maybe this doesn't happen for some of you guys with gentler curves (that sounded weird, but you know what I mean). I wasn't anticipating this, and I don't like the long gap in the ties because I'm worried the rails will not be perfectly gauged apart at that spot. I'm going to have to redo one joint because of this. But it's okay, I'm getting comfortable with the iron.

But for this reason, I'm now soldering the curve joints in place. It works fine, no more difficult than doing it in long straight sections. In fact easier, because if one track is in position already on the curve, you can see exactly how much extra rail is on the inside. Then you can cut it to match the other rail. Solder the next piece on while it's straight, and curve it after it cools. (Side bennie: Joint stays put.) Nail that new track about half way along, pin the rest to hold it in the curve, then address the next joint the same way. "Easy peasy lemon squeezy", as my daughters used to say.

-Matt

     

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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    July 2006
  • From: Bradford, Ontario
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Posted by hon30critter on Monday, May 24, 2021 2:53 AM

Hi Matt,

I'd say that you have mastered the technique! Well done!

Cheers!!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

  • Member since
    February 2008
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Posted by kasskaboose on Monday, May 24, 2021 6:23 AM

The soldering looks fine to me.  I've still not mastered soldering well, but ensuring you have a clean area is essential.  Also critical is using a file to remove excess solder.  Someone mentioned about a file set.  You can get a cheap one from Harbor Freight.  It comes in a case and has various types (ohh, ahh!).

  • Member since
    May 2004
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Posted by 7j43k on Monday, May 24, 2021 9:49 AM

Lastspikemike

Well, since I don't even know what accuracy in laying rails means, much less why it could possibly be important, that may explain why I find making the final connection in a loop of track to be far easier within a curve than between two straights. I don't even draw out the track alignment on the benchwork. I just lay the track from where I start until I get to the other end, then join the loop. Only the turnout locations need to be super accurate for reasons unrelated to drawing a plan. The prototypes were built that way, in the very beginning when the as-built location of railway determined the ROW.  

The gap between the ends of the rails should be very small, less than 1.0 mm if feasible. If you cut the straights you're going to have a larger gap than you need to.

When I do this operation, I typically leave a combined gap (both ends of the rail) of .02" (1/2 mm).  I use a scale in fiftieths of an inch, which makes it easy to measure to the hundredths.

As you can imagine, having a small gap makes it a bit easier to install, plus I'm a fan of expansion gaps in rails.

 

If you cut the curves you will have no gap.  Of course, what I really mean is you leave the curve loose, not nailed or glued down, when you close the final gap. For me, the alignment of the straights needs to be accurate. I prefer minor alignment adjustments to be hidden within the curves. Since I cut to fit with high accuracy the effect on curve alignment is invisible. That's not so if the straight is cut incorrectiy.

If you can use a measuring device and then cut straights to within plus or minus 0.5 mm for both rails rather than simply offering up the rail to be cut and marking it exactly where the cut needs to be......well that explains why you might find straight joints easier, for you.

Well, there you have it.  I have such a device:

https://www.amazon.com/gp/product/B00027959S/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

What do you do if the final joint you make happens to be inside a curve? Or you have no tangent track at all?

 

 

I suck it up and deal with the problem.  My approach is a general case.  If it arises that it isn't appropriate, I do it differently.

If I HAD to make a joint in a curve, I would do it.  HOWEVER, I strongly prefer not to, as I like to pre-solder those joints before laying track.  I then install a "single" piece of track through the curve.  This lessens the chance of a kink in the curve.

If I had no tangent track at all, I would have a very unusual layout.  Perhaps YOU have such a layout.  If it would a big circle (or a small one), I would do the final joint in a curve.  Obviously.  If it were a more complex layout with no tangent track, I would have reverse curves.  If I accepted that as my reality, I would make the final joint in one of those reverse curves.

 

Ed

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