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temp variations

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  • Member since
    December 2009
  • 2 posts
temp variations
Posted by chelydra on Thursday, December 3, 2009 3:01 PM

i have a barn loft to build a layout in. my question is this, there is no heating or cooling system so i will be able to heat or cool when im present. i plan on laying about 200 ft of track. temps will vary from 20 below to 120 above fahr in a normal year. what will happen to the track with expansion and contraction or any thing else unforseen? 

  • Member since
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Posted by locoi1sa on Thursday, December 3, 2009 5:11 PM

 Sign - Welcome

  My clubs layout is in a 105 year old baggage car that gets heat when some one is there. It is 40 years old and still going good. Temp swings is no big deal if you plan for them. Humidity swings is the killer. Gap rails, Paint all bench work as you build, Use good quality lumber, Keep it as dry as possible. If you can seal the room up real good and run a humidifier it would be alright. My portable modules go through some real big temp and humidity swings all the time. I can take them out of my warm and dry house put them in the back of an unheated pickup with a top, Drive through snow and rain and carry them through a parking lot in the rain or snow, Set them up and run trains in an hour.

    Good luck

        Pete

 I pray every day I break even, Cause I can really use the money!

 I started with nothing and still have most of it left!

  • Member since
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  • From: Southwest US
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Posted by tomikawaTT on Thursday, December 3, 2009 6:44 PM

Howdy Sign - Welcome welcome aboard.

My layout space is a non-climate-controlled garage in the Dessicated Desert.  My lowest lows aren't much below freezing, but I'll match your highs any August afternoon.

As Pete said, the big thing is humidity - or, in my case, lack thereof.  Forest products don't like the combination of hot plus dry - it makes perfectly straight boards assume weird and (not so) wonderful shapes.  My solution is to build benchwork with steel studs, which shrug off humidity changes.  I also leave ample gaps at rail joints for expansion.

My suggestion is to make haste slowly.  Get some track down so you can run trains, then watch how it reacts to climate change as you slowly fill in the rest of your plan.

You've picked up a challenge.  Good luck

Chuck (Modeling Central Japan in September, 1964 - in a Southern Nevada garage)

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,330 posts
Posted by selector on Thursday, December 3, 2009 6:52 PM

On another forum I frequent, a fellow who sure sounded like he knew what he was talking about said he had done the math and that NS Code 100 rail in a solid length 100 feet long would lengthen only 1/4" with a rise of 30 degrees.  You can easily accommodate that shift with a series of gaps here and there, none exceeding perhaps 1/16".  Yet, the real utility, as suggested already, is in allowing those gaps to take up much more serious movement in the entire framing due to changes in the dimensions of any organic materials that might attract moisture...such as milled lumber arranged in squares.  Funny, but most of us resort to just that sort of construction. Laugh

The wisdom currently, or general consensus, is that curved flextrack should be soldered to keep the curves as you intend them to be.  The tangents are the places where you use only joiners to allow for the expansiond contraction.  Curves solid using solder to keep your curves in radius, but most tangent track should have some gaps and sliding joiners.  That means you will have to feed the rails on either side of those sliding non-soldered joiners to ensure good power transmission to the engines.

-Crandell

Edit (added) - Here is a website with a calculator.  If you know the coefficient of expansion for NS, you can get the length change.

http://www.ajdesigner.com/phpthermalexpansion/thermal_expansion_equation_linear_final_length.php

And here is the text of a thread from another popular forum.  The author goes by the name of Pete Nolan.

"

As your size, I think you will not need to solder joints, but follow Bobs advice and use a number of feeders.

I did the
expansion calculation a few years ago here, but can't find it. Two 36-inch pieces of nickel silver, fixed at the far ends, will experience nearly a 0.625" buckle during a 40 F. temperature change. My track, like Tony's, went straight up. The track does not expand 0.625", but much less. However, that small expansion causes a large buckle.

Also, Atlas C55 is a lot easier to work with than C80. It's more flexible, and the rails are smaller compared to the rail joiners. I have rather large curves (18" minimum radius). On the previous C80 layout, I had to solder to avoid kinks. I started soldering with C55, then found it wasn't needed. The rail joiners held the curve perfectly. A 2 x 4 layout will have tighter curves, but I'd check before soldering. If it's kinking, then you have to solder--or practice your track cutting a little more.

It's best to solder flextrack with joints in a curve as a straight piece, and then bend it. You'll probably have to pre-bend it to get some idea of the lengths.

Pete Nolan"

A fellow called "Hutch" responded thusly, confirming my claim that we're talking tiny fractions of an inch that sliding gaps can easily take up:

" Pete,

17.1 x 10-6 is the coefficient of thermal
expansion for nickel silver from http://www.goodfellow.com/csp/active...el_Silver.HTML

If you use the calculator at
http://www.ajdesigner.com/phpthermal...nal_length.php

Assuming you start with a length of nickel silver 72" long, and you rise from 50 degrees F to 90 degrees F, you get a change in length to 72.02736 inch for a delta of .027 inches. Three hundreds of an inch is much less than .625". Where did I go wrong?

Edit.....

Oh... I see now, you are saying the .027 inches of
expansion will force the joint .625 inches upward...

Never mind me "
  • Member since
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Posted by Metro Red Line on Friday, December 4, 2009 2:11 AM

tomikawaTT

My suggestion is to make haste slowly.  Get some track down so you can run trains, then watch how it reacts to climate change as you slowly fill in the rest of your plan.

 

 

Or, lay down your track during the hottest days of summer :)

  • Member since
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  • From: Sierra Vista, Arizona
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Posted by cacole on Friday, December 4, 2009 9:17 AM

 Our 20 x 40 foot HO scale layout is in a building with no central heat or air conditioning.  Temperatures range from below freezing to 120 degrees, and humidity ranges from 5 percent to 90 percent, depending on the time of year.  Track expansion and contraction is not the problem, it is the expansion and contraction of the wood framework with changes in humidity and temperature.

We solved the problem by building the layout on hollow core doors covered with two layers of 1/2 inch thick Sound Board.  Every other flex track joint is not soldered to allow for some expansion and contraction of the rail itself.

Prior to building the layout, we conducted an experiment.  Two lengths of Atlas nickel silver flex track were placed outdoors in full sunlight in July, when the air temperature was over 100 degrees.  The actual rail's temperature was measured at over 130 degrees (the highest the thermometer could read).  The length of the two pieces put together was carefully measured, and they were then put into a freezer overnight.  They were again measured when at a temperature of zero degrees.  The rail had contracted only a few thousandths of an inch over a six foot length.

Wood expands and contracts more than that.

  • Member since
    December 2009
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Posted by chelydra on Saturday, December 5, 2009 10:05 PM

thanks guys, now i can move ahead without having a roller coaster. chalydra 

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Posted by Allegheny2-6-6-6 on Sunday, December 6, 2009 10:52 AM

 Temp variations may or may not have a big effect on your layout but humidity definitely will as stated earlier. I will play hell on scenery and track work a like., but rather then digress and repeat the advice given what about your own comfort? Are you really going to want to work on your layout in sub zero temperatures or when it's 100 degrees plus up in a bar loft. Being a life time farm boy I know all too well how hot it used to get up in the hay lofts of our barns and we're not in a part of the country where we experience extreme weather changes. I have a hard enough time gluing very small pieces together under normal circumstances I couldn't even imagine trying to glue small pieces on in 10 or 20 degree temps.

 I have a 30'x40' pole barn where I work on my hot rods and motorcycles. I added on another 40' long section to the back for a layout room. I have yet to pour  the concrete floor so when the funds are available I intend to install radiant floor heat. The biggest mistake I made in the front shop. Heating the building is really no big deal and not very expensive. I have a 120,000 BTU gas fired forced hot air furnace I picked up on Craigs list for $300 and hung all the duct work myself. The key is the insulation. I had the company install the insulation as they were building the barn. They sandwiched foam insulation board between the wood frame and the corrugated sheet metal which covers the outside of the building. with a couple of commercial ceiling fans it keeps the place nice and toasty warm in the winter.

The first winter the building was up it had no heat so all I used was a space heater and it was enough to take the chill out. I got a deal this spring on 1" foam insulation form Lowes so I glued it to the existing foam board with construction adhesive. I just covered the walls in most places with 4'x8' sheets of peg board becasue it was cheap and on the lower ares 4'x8' sheets of T-111 playwood.

They key is insulating your loft, when properly insulated even with a small heater of some sort you'll have the advantage of natural convection (heat rises and the insulation will help keep it in.the area) I bet if you take the measurements down to your local home center and ask someone at the construction desk It won't cost you as much as you might think.

Just my 2 cents worth, I spent the rest on trains. If you choked a Smurf what color would he turn?
  • Member since
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  • From: Sierra Vista, Arizona
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Posted by cacole on Monday, December 7, 2009 6:15 AM

Excellent advice from Allegheny 2-6-6-6 concerning your own comfort.  Pay more attention to that in your barn loft instead of worrying about the track.

Even with propane space heaters, because our clubhouse has concrete block walls and no insulation, it is so cold at this time of year that my fingers begin to get numb after being in the place for a short time, even if I'm wearing thermal underwear and sweats.  Definitely not conducive to working on small parts or trying to lay track using latex caulk as an adhesive.  Even operation becomes a chore when you're shivering (or sweating).

Think of it from the standpoint that if you're comfortable, your trains are comfortable.  I was a farm boy from Illinois.  A barn loft can be the most bone chilling or sweltering place you can find.

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