Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Solder it or Gap it?

4610 views
29 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    December 2004
  • From: Rimrock, Arizona
  • 11,152 posts
Solder it or Gap it?
Posted by SpaceMouse on Monday, August 31, 2020 5:19 PM

I've always been told that you have to leave a gap between pieces of track to allow for expansion. I don't have to worry about that here in Arizona because we seem to have a permanent over 100 heat wave going on. 

On the other hand the best advice on YouTube University is that you solder all the joiners and stagger the joints to keep the track from buckling.  

I figure that you guys will know all the pros and especially the cons of both methodologies. 

Chip

Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.

  • Member since
    January 2009
  • 5,355 posts
Posted by RR_Mel on Monday, August 31, 2020 6:15 PM

It might not get as hot here in Bako (Bakersfield) but the higher triple digits are pretty common.  I eroded when we moved to Bako.  I built my layout in our garage and soldered all the joints on my Atlas code 83 Flex and it took a couple of summers and heat really dinged my track.  I had used ballasted white glue on all of my viewable track and just track nails on my hidden track.  One day I ran a passenger train around my layout and it didn’t come out of my mountains.  The well glued track did well but three sections of un glued flex track had exploded.  The rails broke loose from the ties in three sections of flex track.  Of course it was all hidden track and the most difficult to replace.

I now leave expansion joints in my track.


Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 22,267 posts
Posted by selector on Monday, August 31, 2020 6:42 PM

Chip, one-hundred feet of contiguous Code 100 N/S rail will expand or contract longitudinally only 6mm (0.25") with a change of 30 D Fahrenheit.  Three or four non-soldered joiners along that 100' will handle any thermal expansion or contraction if the gaps start at about 1/16".

What most of us find is that, since almost all of us use milled lumber for our baseboard/layout, and since wood changes in dimensions across the grain when humidity rises and falls by about 30% either way from initial state (45%-55%), the rails are going to buckle, sproing, or retract and break solders when humidity changes substantially.  The ties, if solidly affixed to the wood, will attempt to ride along with the expansion on axis, while the rails want to do their own thing.  Eventually, those teensy spikehead details throw in the towel.

As a result, I solder most of my joiners, maybe 80%, especially along curves, and I run a dehumidifier all year set to shut off at 48% and to start drying at 65%

  • Member since
    February 2018
  • From: Great Plains
  • 2,272 posts
Posted by York1 on Monday, August 31, 2020 6:47 PM

My layout is in a first floor bedroom in our house.  The temperature doesn't vary more than five degrees year 'round.

I first started by soldering my flex track curves because I had issues of the track curving incorrecty at the joints.  Later, I soldered every joint.  My layout is only two years old, but, knock on wood, there haven't been any problems yet.

York1 John       

  • Member since
    January 2009
  • 5,355 posts
Posted by RR_Mel on Monday, August 31, 2020 7:04 PM

I’ll add some more info on my garage.  I had never checked the temperature in our garage (2 years in the new house) and after the problem I found out the temperature swing between winter and summer was 35° to 106°+ or 70°+.

After the tragedy I had an additional R30 added to the attic.  The swing now is under 34°, I still leave adequate gaps in my track!!!!  I never want to go through that again.   


Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

  • Member since
    February 2002
  • From: Reading, PA
  • 28,926 posts
Posted by rrinker on Monday, August 31, 2020 8:03 PM

Last two layouts, I soldered two pieces of flex together and used that for curves - so even though there is a joint in the middle of the curve, which is unavoidable in a 90 degree or more curve unless it's a really tight radius, the rails and joiners were all soldered prior to forming the curve. The joints ens up not being parallel to one another, although since they are soldered I don't think it matters much, they won;t kink like unsoldered joints.

 I also used two pieces of flex soldered together whereever I could for straignts. The joints between two pieces of my extra long 6 foot sections was left unsoldered. Each soldered pair had feeders, so the unsoldered joint was just a seconday electrical path, not a primary one.

 It worked for two previous layouts, I see little reason to change. I am using wood (plywood, mostly) for the benchwork and subroadbed this time, so there is ptential for move movement in the supportign structure. Last two layouts were foam. But since essentially every other joint is not soldered, there should be plenty of room for things to move. My basement is fairly well sealed now, with vapor barrier and insulation on all exterior walls, and a full drop ceiling. There's heat, but no ac. I do have a dehumidifier which seems to be able to maintain 45 percent on the hottest and most humiod days. It was alte winter when the work was finished, but it stayed warm even though I still have to hook the thermostat back up (I'm thinking I will not need to actually use the heat any more - which should save some on the heating bill - the insulation combined with the furnace and water heater running seem to make enough heat). It wasn't horribly dry, but we had a fairly wet winter (rain, almost no snow). Have to see how dry it gets this year. That will probably be my biggest issue - getting too dry now, since witht he foundation sealed and insulated, the moisture that was getting in and giving the whole basement a damp smell is no more. Now it just smells like fresh cut wood. And laundry soap, over by the laundry area. 

 I should have some track down by the time it gets cold and dry. So we shall see how it holds up. 

                                 --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    January 2009
  • From: Maryland
  • 9,638 posts
Posted by ATLANTIC CENTRAL on Monday, August 31, 2020 8:13 PM

I have been soldering all my rail joints for 50 years, only leaving gaps/plastic joiners were needed for electrical reasons (I run DC).

Many of my blocks are/have been 50' or longer.

Never had any problems.

Sheldon

    

  • Member since
    June 2003
  • From: Culpeper, Va
  • 8,101 posts
Posted by IRONROOSTER on Monday, August 31, 2020 8:30 PM

When I soldered every joint, I had rails in one place break out of their molded spikes.  So now, I leave a few unsoldered joints on tangent track.  Curves still have every joint soldered.

Paul

If you're having fun, you're doing it the right way.
  • Member since
    July 2007
  • From: Yorkton, Sk, Cnd
  • 414 posts
Posted by wvg_ca on Monday, August 31, 2020 10:03 PM

all track sections, whether flex or sectional, are soldered ... the only exception here is the turnouts are not soldered, on either end ..

the layout is fifteen feet by sixteen feet, with a 2.5 per cent grade on most of it .. it has been trouble free for seven years now .. [oh, it's HO, mostly Atlas code 100, with Atlas number six Custom Line turnouts]

  • Member since
    February 2001
  • From: Wyoming, where men are men, and sheep are nervous!
  • 2,494 posts
Posted by Pruitt on Monday, August 31, 2020 11:12 PM

I've lived and built layouts nearly all over the country - Seattle, New Jersey, South Carolina, Lompoc California, Orlando and Wyoming. The only place I ever had track issues was in New Jersey, because of benchwork movement from changing humidity (a dehumidifier fixed that).

Unless you have huge runs of tangent track, changes due to temperature will not generally be an issue. I just eyeball a business card thickness-sized gap at all rail joints on tangent track, and call it good. It's always worked.

I solder all joints on curves, because that's the only way I can get a smooth path around the curves. They've never given me a problem anywhere except as I said in New Jersey.

Since AZ is generally very dry, I wouldn't worry about it. You'll be fine.

  • Member since
    July 2006
  • From: west coast
  • 5,510 posts
Posted by rrebell on Monday, August 31, 2020 11:28 PM

selector

Chip, one-hundred feet of contiguous Code 100 N/S rail will expand or contract longitudinally only 6mm (0.25") with a change of 30 D Fahrenheit.  Three or four non-soldered joiners along that 100' will handle any thermal expansion or contraction if the gaps start at about 1/16".

What most of us find is that, since almost all of us use milled lumber for our baseboard/layout, and since wood changes in dimensions across the grain when humidity rises and falls by about 30% either way from initial state (45%-55%), the rails are going to buckle, sproing, or retract and break solders when humidity changes substantially.  The ties, if solidly affixed to the wood, will attempt to ride along with the expansion on axis, while the rails want to do their own thing.  Eventually, those teensy spikehead details throw in the towel.

As a result, I solder most of my joiners, maybe 80%, especially along curves, and I run a dehumidifier all year set to shut off at 48% and to start drying at 65%

 

Number seems a bit high but even if true, how many people have 100' straight mainline. Ussually people have problems with expantion because the put their track down on ply, thats why I use foam. It only shrinks notably when new ( most people that buy at home stores never see stuff that is new enough to worry about.

  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
  • 9,618 posts
Posted by SeeYou190 on Tuesday, September 1, 2020 6:27 AM

York1
My layout is in a first floor bedroom in our house.  The temperature doesn't vary more than five degrees year 'round.

Me too. My layouts have always been in the "normal" house area and have been rigidly kept at the same temperature year round.

No problems.

-Kevin

Wink Happily modeling my STRATTON & GILLETTE RAILROAD. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

  • Member since
    February 2002
  • From: Reading, PA
  • 28,926 posts
Posted by rrinker on Tuesday, September 1, 2020 8:49 AM

 It's not the rail - it's the wood supporting structure.

It's the rail on the prorotype, because of how long a section of continuous welded rail is, and also depending on where inthe country you are, there's a considerable temperature swing. Here we can get to the single digits regularly in winter, and high 90's regularly in summer. If your layout space varies that much, perhaps you should consider a different layout space - one you can keep within a human comfortable temperature range, which will result in very little metal movement.

 Humidity swings though, with wood structures - maybe my slow construction progress is actually a good thing, as the wood sits in my basement for a while before it gets used - although not really long enough to truly season to the environment. It's it's constantly dry, or constant high humidity, it should be fine. WHen it swings, like it does here, between very dry in winter to very humid in the summer, if you don't control humidity in the layout area, it will be a problem. If you can't control it, alternative building materials may be for you - like steel stud benchwork. Humidty change will have little effect on that.

                                      --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    July 2006
  • From: west coast
  • 5,510 posts
Posted by rrebell on Tuesday, September 1, 2020 9:13 AM

My construction is a box of 1x4's and the foam is caulked on top of it, no wood problems.

 

  • Member since
    February 2008
  • 1,541 posts
Posted by kasskaboose on Tuesday, September 1, 2020 12:15 PM

IRONROOSTER

So now, I leave a few unsoldered joints on tangent track.  Curves still have every joint soldered.

Paul

 

 
I def solder joiners for curved track and not for straight.  When starting in MR, one of my biggest Qs was how to solder curved track.  I learned by trying!
 
Clearly, adding spacing to track depends on multiple factors.  Geography of the layout in a house, part of the country, how much sunlight, moon phase are just some (of many) other factors. It seems no two have the "right" answer.
  • Member since
    April 2004
  • From: Ontario Canada
  • 3,367 posts
Posted by Mark R. on Tuesday, September 1, 2020 2:34 PM

I'll throw in my two cents ....

My layout is almost 25 years old. The ONLY time I had a few cases of track buckling was in the first two years and it was only three different spots. Every joint on my layout is soldered .... at least I thought they were when I discovered a dead spot on the layout a couple weeks ago. Turns out I missed soldering a joiner and for whatever reason, the joint quit conducting !

My layout is in a room that is heated / cooled the same as the rest of the house. Once my (green) lumber climatized to the environment, I have never had any further issues. Remember, it's not the track moving, it's the benchwork.

Mark. 

¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ

  • Member since
    January 2004
  • From: Canada, eh?
  • 11,016 posts
Posted by doctorwayne on Tuesday, September 1, 2020 3:32 PM

I solder all rail joints, then cut gaps for isolating some track sections, where required, cementing Plastruct ABS into them. 

My layout is strictly DC, in a basement room, neither heated nor cooled (the temperature varies little, due to good insulation), and a dehumidifier runs, as needed, all year round.  No issues at all with track.

Wayne

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 22,267 posts
Posted by selector on Tuesday, September 1, 2020 7:13 PM

rrebell

 

 ... how many people have 100' straight mainline. Ussually people have problems with expantion because the put their track down on ply, thats why I use foam. It only shrinks notably when new ( most people that buy at home stores never see stuff that is new enough to worry about.

 

 

Quite my point.  Who has that much linear feet of 'welded' nickel-silver in ANY code?  So, thinking of saving one's rails from the dreaded buckle by assuming it's due to thermal expansion is misguided.  It's many times more likely to be the wood expanding or shrinking.

  • Member since
    September 2020
  • 7 posts
Posted by Clark G on Friday, September 4, 2020 2:19 PM
My HO layout, a couple years old, is a 5x9 mobile layout in 3 5x3 sections bolted together.  It gets moved to shows several times a year, to a fire station, armories, poorly climate-controlled buildings, etc. as well as my basement (well not this year w/ Covid).  I run a DCC buss under the rail and enough track feeders that at no point is the track more than one joint from a feeder.  (With a mobile layout, you can set a section it on its side to make wiring easier and not lay on your back!)  None of my joints are soldered and on other layouts I only solder if necessary, which is rare.  I have not had a problem with track expansion or getting power through unsoldered joints.  On large curves, usually working a slight bend with plyers and needle nose plyers on the ends of flex track can make a smooth curve without solder.
Our club HO layout started by previous members has a lot of soldered joints.  I have had to redo several joints where, after many years, power did not get through usually by just heading the joint.   The layout also has a lot of older Shinohara turnouts where point rails have come loose from the throw bar.  The ones with unsoldered joints are much easier to repair.  It is also easier to modify layouts where joints are not soldered.
Just my $.02,
Clark
 
  • Member since
    November 2002
  • From: Colorado
  • 3,977 posts
Posted by fwright on Thursday, September 10, 2020 1:25 PM

I didn't believe rail expansion was significant until I saw it for myself.  Club had set up HOn3 modules (code 70 rail) inside a building in Denver for Christmas display.  Everything running/working fine.  Heat in the building was kept on. 

Came in next day to set up for the evening.  Sunlight from a window was falling on track handlaid across a beautiful trestle.  All joints on the 4ft module were soldered, per our practice.  One rail had sprung into a beautiful bow, taking out the spikes from the ties.

Once a gap was cut in the rail, it was re-spiked to the ties, and all lived happily ever after.  If I had not been there in person, I would have never believed the story, either.

Fred W

  • Member since
    August 2006
  • From: Nashville, TN area
  • 535 posts
Posted by hardcoalcase on Tuesday, September 22, 2020 9:23 PM

rrinker

 It's not the rail - it's the wood supporting structure.

--Randy 

Agreed.  My first room-sized layout, with stick lumber (1x4" benchwork, 1/2" ply subroadbed), was in a climate-controlled basement, but the humidity could vary (via a sump pump); and one day I found several curves that stepped outside their alignment.

The next two (room-sized) layouts were built using 3/4" 8 ply birch plywood, ripped to 1x4"s, which, despite being stored in various unfriendly climate conditions for extended periods, remained straight and warp-free - and the track behaved too.  

I've found that, stick-for-stick, the cost of the birch ply vs. high-grade dimentional lumber, is about the same. 

Jim

  • Member since
    June 2007
  • 7,868 posts
Posted by riogrande5761 on Wednesday, September 23, 2020 7:36 AM

I haven't used any birch or more expensive wood.  The wood I have used has basically been installed without track for some months so hopefully it's had enough time to settle.  A dehumidifier keeps the air around 50-55 % during summer and during the cold months it may drop a bit lower.

I didn't have any problems in a very similar environment in my last basement and I soldered rail on curves but left straight track with a slight gap.  I'm doing the same with the prresent layout - gap of about the width of a credit card.

Rio Grande.  The Action Road  - Focus 1977-1983

  • Member since
    December 2004
  • From: Rimrock, Arizona
  • 11,152 posts
Posted by SpaceMouse on Sunday, October 11, 2020 2:30 PM

When y'uns say you put a drop down on every piece of track, does that include turnouts?

Chip

Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.

  • Member since
    January 2004
  • From: Canada, eh?
  • 11,016 posts
Posted by doctorwayne on Monday, October 12, 2020 2:03 AM

rrebell
...how many people have 100' straight mainline....

Well, mine's certainly not straight, but because my DC layout was built using common rail, I have at least one stretch of well-over 100' without gaps. 
As mentioned previously, all rail joints are soldered, and all gaps to accommodate isolating trains to allow others to pass on a parallel track have the gaps filled with ABS plastic.  The room is neither heated nor cooled, but is well-insulated, and a dehumidifer runs year-round as all of the layout is in the basement.  No track issues in over 30 years.

Wayne

  • Member since
    January 2009
  • From: Maryland
  • 9,638 posts
Posted by ATLANTIC CENTRAL on Monday, October 12, 2020 8:42 AM

SpaceMouse

When y'uns say you put a drop down on every piece of track, does that include turnouts?

 

Well, I would say no....

I have been involved in the building of large DCC layouts where the owners installed all those drops every 6', but never got around to running all that bus wire and hooking up all the drops. Those layouts ran fine with just a single feed to each of several power districts and soldered rail joints in those districts.

I'm not saying no allowance should be made for expansion and contraction, but that issue, and the feeder issue, are way over blown in my experience. And my experience does include DCC even though I don't use it myself.

I had lots of friends convert their DC layouts to DCC by just tapping into their cab control wiring with no problems.

None of my 50'-60' blocks have ever had power issues with just a single feeder in DC, or expansion issues with soldered rail joints.

Chip, how big is this layout you are building?

Sheldon

    

  • Member since
    December 2004
  • From: Rimrock, Arizona
  • 11,152 posts
Posted by SpaceMouse on Monday, October 12, 2020 8:50 AM

ATLANTIC CENTRAL
Chip, how big is this layout you are building?

Small by comparison. 8 x 13 U-shape. 

There is an upper level on the lower section above staging.

BTW: My bus wires are run and easy to reach from the edge of the layout.

Chip

Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.

  • Member since
    January 2009
  • From: Maryland
  • 9,638 posts
Posted by ATLANTIC CENTRAL on Monday, October 12, 2020 9:47 AM

On a layout that size you have nothing to worry about. Solder most of the rail joints, maybe have two power districts, and forget the bus wires, just my opinion, based on past experience.

Sheldon

    

  • Member since
    July 2006
  • From: west coast
  • 5,510 posts
Posted by rrebell on Monday, October 12, 2020 9:54 AM

I would solder it all and then cut any gaps. I would run the buss wire just for ease of use and would run two areas just to make trouble shooting easier.

  • Member since
    July 2006
  • From: west coast
  • 5,510 posts
Posted by rrebell on Monday, October 12, 2020 10:03 AM

doctorwayne

 

 
rrebell
...how many people have 100' straight mainline....

 

Well, mine's certainly not straight, but because my DC layout was built using common rail, I have at least one stretch of well-over 100' without gaps. 
As mentioned previously, all rail joints are soldered, and all gaps to accommodate isolating trains to allow others to pass on a parallel track have the gaps filled with ABS plastic.  The room is neither heated nor cooled, but is well-insulated, and a dehumidifer runs year-round as all of the layout is in the basement.  No track issues in over 30 years.

Wayne

 

A lot of the expantion problems come with the way you build a layout, the sub roadbed and such. Mine have been foam on top of 1x4's, then cork and flextrack, none of which really for practical model railroad aplications, expand or contract at all (foam only shrinks when first made and a short time after, cork if it like Midwests dosn't srink because it is made from outer bark and fillers).

  • Member since
    February 2008
  • 1,541 posts
Posted by kasskaboose on Monday, October 12, 2020 10:04 AM

You'll probably get very different answers based on temperatures, house locations, moon phases, etc.  

What works for me is to solder ALL feeders to the track and and solder only joiners on curved tracks. All my track is Code 83 ME and Atlas turnouts.  This setup might not work for everyone, but that's fine.  Do what works.  

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!