OK, first a little info.
I'm like forever building a 19.5 x 28 HO layout in my basement which is dehumidified in summer and in winter the upstairs has humidity added when the furnace kicks on, but the basement does not except from air exchange. Temperature ranges from 62 in winter to 69 in summer when the air conditioning isn't on upstairs. So, with a somewhat large layout in this environment there is a lot of wood susceptible to at least some expansion and contraction which in turn, reduces or applies pressure on the track connections.
I solder my flextrack on the curves and also where there may be 1' or less straight sections. The rest I allow a gap of around .020" between each piece for any expansion/contraction. Occasionally, some of my track sections get a gap that is too large, say .100" rather than the .020 or so. The larger gap is more likely due to my construction lapses rather than actual expansion/contraction. While I haven't had any operating problems or DCC power issues (each track piece section has 22ga. bus feeds), I have had more than one person tell me I REALLY should fill in those gaps with styrene using a CA glue and then filing to make a smooth connection. I have seen a few references on the Internet to do this as well.
My questions are:
Doesn't this defeat the purpose of allowing room for expansion/contractions?
Won't this introduce the same problems as if I had just soldered the rail together to begin with?
Won't contraction break the bonds and expansion bulge the rails?
Do you fill too-large gaps with styrene? If so, do you CA both ends and then shape and file smooth?
Appreciate your thoughts on this.
Thank you. Ken
Ken,
A 7-degree temperature swing isn't much at all, and it sounds like the humidty doesn't vary by much either. Unless you have really crappy wood and all straight track, I'd think you could get by without expansion gaps. You certainly don't need to gap every piece.
As a data point, my layout (before I tore it down and started over) was about half the size of yours (about 14x16), but I'm sure it experienced much greater temperature/humidity swings. However, I soldered all rail joints and filled all insulating gaps and never had a problem.
Either way, if you like having the gaps and they don't detract from the layout's running qualities, then I see no reason for you to change they way you implement them.
Steve
I agree largely. You don't really have an issue to be concerned about, except if the gaps bother you or your models sufficiently, or the observations of your guests bother you sufficiently, that you feel you should do something about the worst ones. I had some plainly too-large gaps in difficult sections to lay, and I did use styrene. I don't find it very pretty, but I'm not a patient or skilled modeller, so I got what I placed there and how I finished it. I have seen images where patient and skilled modellers produced very clean and essentially invisible fillers once the tracks were weathered.
But you don't appear to have anything to worry about based on your initial post. Your basement seems to be largely stable in terms of temps and humidity. So it would be for the sake of appearances and function for the trains that you would tackle this slight matter.
My
The other posters have looked at this from the point of view of whether or not you need gaps to allow for rail movement. I intend to look at the opposite aspect - do wide gaps interfere with operations. IMHO, a gap the height of Code 100 rail is acceptable - I have several along the interface lines between fixed and removeable track that are at least that wide (wider in cold weather, narrower when the temperature goes above 100F.)
Granted that such gaps LOOK ugly. If you are going to be taking close-up photos or videos, or if your railroad is intended to be a museum showpiece, then the rail should be re-laid to close the gaps. If not, assuming that trains don't derail at the wide gaps, just put them on disregard. If the gaps cause derailment problems, bevel the sharp inside corner of the rail at the joint so there's nothing for a flange to pick. The only excuse for completely filling a gap is to simulate all-welded rail - in which case I would prefer metal (solder) to plastic.
But, if it IS all-welded rail, how do you explain the rail joiner?
Chuck (modeling Central Japan in September, 1964 - with wide, unfilled gaps)
There are two reasons for gaps in the rail. One is to handle rail expansion or benchwork shrinkage (more likely) in changing conditions. No harm in leaving those gaps unfilled, if it doesn't effect the operation of the trains. If the gaps should happen to close in some conditions, no harm done.
The other reason for gaps is to create electrical blocks. In those cases, filling the gaps with styrene filed to shape and painted is a good idea, because you never want those rail ends to contact each other to avoid electrical problems.
Layout Design GalleryLayout Design Special Interest Group
Like one of the previous posters, aside from electrical gaps, every joint on my 13X25 foot layout is soldered. The only time I had ANY problems with the track-work kinking was in the first year the bench-work was constructed. I attribute this to the fact much of the wood was either green or wet and was still climatizing to its current environment.
Once wood assumes the moisture content of its environment, overall expansion and contraction is greatly diminished, almost to the point of being negligable in terms of kinking the track itself. I've read numerous articles that state when using wood for construction of things like bench-work, it's best to bring the wood into the area where it will be used and allowed to climatize for as long as possible (1 year is recommended !) before actually using it.
Since that first year's few problems, I have had nary a kink or gap show up in over 15 years.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
no one really answered your question
"Do you fill too-large gaps with styrene? If so, do you CA both ends and then shape and file smooth? "
I too would like to know
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
If you're making an insulated gap between blocks, you can use plastic cut to the rough shape and then filed/sanded to match the rail contours. I've seen several books and articles talking about that.
FWIW I've found roadbed expanding and contracting to be more of a problem than rail, my last layout used Ribbonrail made of Upson board. It works well, but especially the first time thru the seasons it tends to expand and contract.
gjvjr50 wrote: no one really answered your question "Do you fill too-large gaps with styrene? If so, do you CA both ends and then shape and file smooth? "I too would like to know
I guess it depends on what you consider "too-large". Myself - if it's wider than the thickness of a dime, I fix it. If the offending rail is rather short, I remove that piece of track and cut a new one to the proper length and use the "too short" else-where.
If replacing the piece of track isn't an option, I'll cut a small slice of rail the same size as the gap ..... insert it in the joiner and solder everything up tight. Some slight dressing with a file may be required for a perfect joint.
The potential problem with gluing a piece of plastic in the gap with CA is that the capillary action of the CA will get into the joiner and act like an insulator at that joint .... I've seen it happen !
The important gaps to fill are the ones between different electrical blocks where the polarity could differ. For instance, the gaps between a powered frog and the associated rails. You don't want a scenario where the rails expand and touch creating a short circuit.
I filled the gaps on my layout using appropriate thickness of styrene and gel CA trimmed and filed to shape. I used white styrene but David Popp's suggestion in the latest MR to use colored styrene to avoid the visually jarring bright white line seems like a good suggestion.
The other gaps are just about your threshold of pain visually. If its wide enough to make the car wobble you probably want to fix it to prevent derailments.
chris
btw- the reason humidity is a problem is it causes the underlying benchwork to expand and contract resulting in potentially buckled track. I have not experienced it but my layout is in a humidity controlled basement. Temps vary wildly but my small layout does not have runs long enough for thermal expansion to be an issue on the rails, and it is a non-issue with wood.
If the gap is too large, three things are possible.
- Visitors may notice it, = If it is that big and it bothers you, fill it.
- The equipment wheels may drop in it. = If so, fill it.
- The track may pull back out of the rail joiner. = Fill it with a small piece of rail and solder it.
If none of the above and it doesn't bother you or the trains you run, don't worry about it.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
Thank you all for the many comments on this topic. I guess I really fretted over nothing. The consensus seems to be fill it if it bothers me or it causes a tracking problem, otherwise, leave it be. And that's exactly what I'll do. Saves me a lot of work because there are only a few in the .100 gap space.
Thanks again, folks. I appreciate your freely offered comments from your knowledge and experience much greater than mine. Ken
Now that it's cooling off I'm getting some big gaps opening up. I'm thinking about using JB Weld epoxy for a gap filler. Anybody have any thoughts on that? (none are insulated)
It's more the wood and cork expansion/contraction you need to worry about. I think humidity changes are worse than temperature.
First, see my post above.
Second, if you fill all of your gaps now and then the weather cycle next year tries to close the gaps, the track will buckel.
I would go through a two year cycle without doing anything if you can. If this is the first year with your layout, the wood may be drying out as well. Once everything gets stabilized, then you can fill the gaps during the warm season.
I am in SW Wisconsin and we have large differences in humidity from summer to winter, even with climate controlled heating/cooling. Consequently, my rail on 15-foot straight lengths can buckle, or get pushed out of a straight line in winter. It's the wood base that changes.
I leave a few rail gaps to compensate. I also use Atlas insulating rail joiners where I need an insulated section. They look OK to me, and they maintain alignment to good degree.