Well this is a first. I laid a lot of track on the layout in the spring. I ensured that each piece of flex had at least a thumb nail width of gap. Track was put down with silicon sealant. I was fully prepared to have to fix kinks due to heat expansion (layout is in a garage in El Paso). Well the opposite occured. It has gotten warmer and the gaps have gotten bigger. It is bad enough in some places that I am going to have to re-lay the track. Just wondering if anyone else has experienced this.
Oh ya, my one attempt at a big layout, I had 2 legs of my yard bow, and 2 leg of my yard contract and open joints. frustrating.
Yes the wood moisture content lowered, thus shrinking, hence bigger gaps, it did it to me to one spring, until the summer rainy season humidity restored the wood's moisture content. Rob
I think Rob is on the "right track" except it sounds like your wood has been absorbing moisture during the summer and thus expanding faster than the heat is expanding your track. It is generally a good idea to paint all exposed wood so as to seal it (or at least slow down) drying out and moisture absorbtion.
Preventing Humidity I've heard one way to combat the humidity content of your benchwork from changing is to seal it once you have it constructed. You can do so by painting it or hitting it with a good coat or two of wood sealant. Something that will prevent the wood from absorbing moisture in the summer and losing it in the winter is the idea. Might be worth doing after you've fixed all the gaps to prevent it from happening again. Just a thought. Bob
Considering the hot dry conditions in summer in Texas (opposite of the humid summers in the majority of the rest of the country), this is the most likely scenario for your dilemma. I've had the same problem with some of my outdoor construction projects here in Fort Worth - I build something in the spring and by summer the wood shrinks and dries under the hot sun (combined with no significant rain to speak of) - then in the spring it all expands again once the rain and humidity are in full force. Fortunately my layout doesn't have a problem because it is in a temperature- and humidity-controlled environment.
I was assuming that El Paso would be more like our climate here in Tucson (very dry most of the year, with a humidity increase only during monsoon season (i.e. now). If the wood subroadbed was drying out/shrinking, that wouldn't create gaps in the rails, but would tend to have the opposite effect of compressing the rails.
If it wasn't for my water sprinklers my yard would actually be crunchy right now. Some of the problems Tony is having are reflective of some of the feedback I've had from other modelers in this area. It's part of the reason when I was having my house built I decided to spring for the extra square footage so I would not have to put my layout in my garage. It should be interesting to see what happens next year, though. I'll start working on my garden layout so I'm sure I'll encounter problems I haven't even imagined yet.
Sounds like you guys might be better off using a metal frame with Foam on top instead of wood, that would cut down on the amount of expansion and contraction. I'll add that this won't help Tony any as his trackwork is already down.
Yes, a metal frame is definitely something to consider. If it wasn't for the fact that wood is just easier (for me) to work with, I may have chosen that route. I do agree that this is not a lot of help for Tony and his trackwork, but, perhaps it will help someone else when they go to begin construction on their own layout. The environment that your layout is in will affect the way you go about construction. The purpose of this forum is to inform and educate, sometimes by learning how someone else did it the "wrong way". As Fotheringill would surely agree, many of us are running a division of "The Lessons Learned Line". I know I am - I'm getting ready to rebuild a sizeable chunk of my layout after discovering that what I had on paper doesn't necessarily translate to wood and rail. Too bad I didn't discover this until I had already laid over 400ft (yes, 1:1 scale feet!) of track. At least Tony knows what he needs to do - relay a few sections of track and gap according to the his new-found knowledge.:cowboy:
We have actually had a real wet spring. Probably due to the rain. I think I'll just let it go for now since everything will dry up in a few months. Sealing the layout wood will be a big pain since it is already up. Once it is dry maybee I'll bite the bullet. I'll have to fix a few pieces of track but I may just put styrene spacers in on some of the wider gaps.
To continue in the vein of TexasNS in assisting the future builders and passing empathy for Tony's humidity-caused problem, I accidentally avoided the problem. I do not have a lot of carpentry tools or skills, so I opted for furniture quality PVC (1-1/4") from Arf and Running, precision cut to my size needs. About the same cost as kiln dried true lumber - and a heck of a lot less than metal. And lighter and easier to work with. All wood that I used for supports and risers was primed with Kilz before installing and then spot sanded where ever gluing was the fastening method. My N scale is on a non-enclosed patio and I have not had any of the commonly experienced rail problems. It is located in Garden Grove, California which is about 15 miles from the coast. We have pretty stable temperatures and humidity. From what I read I guess that I am very lucky - and I do feel that the PVC framework contributes greatly to that luck. I wasn't thinking of the moisture when I decided to use it - just avoiding a personal weakness - little skill and less tools. Tony, I sure hope that you find a solution that will prevent your having to go thru this every year. Good luck in that endeavor. As to the stability of the PVC framework, yesterday (7/29/08) it experienced a 5.4 earthquake, with an epicenter 24 miles away. Pictures off of the walls, shelf display train derailed and turned on its side, grandfather clock stopped, cabinet doors flew open, a light statue was turned 180 degrees, etc. Nothing out of place on the layout and no cracks in scenery. The next earthquake has been my "other shoe" ever since I started on this layout building using the PVC frame. Now I can rest - I hope.
Respecting laws Oh fine - just fine! Facing my first garage layout (helping repair someone's), I asked you guys for a little help planning for track expansion and contraction. We talked about nails, glues, 'floating' and gaps. But now you're telling me that if track is laid during cool months, it can actually shrink when ambient temperature rises! You got no respect for the laws of Physics! Scott First day of my first Econ class, the prof explained, "Physics is a science where, when you let go of a ball, it'll fall, predictably, to the ground. On the other hand, Economics is a science (supposedly) where, when you drop the ball, it can fly up or sideways for 100 different reasons." I think you guys are laying tracks with Economics instead of Physics! (Yes, I saw the posts about wet wood expanding faster than rails - thanks!)
My layout is also in a garage but the garage doors and windows are sealed shut and the garage is insulated. This helps with the big temperature swings considerably.
This is just the way God designed everything. Wood (trees) were designed to be very efficient at sucking up and storing moisture when it's available. Apparently, he never intended us to chop them down and make subroadbed out of them. Maybe that's why he allowed man to create plastic and extruded foam. Wow, am I sounding like a tree hugger....
I guess it would be ok if I sound off here. Wood, humidity, different types of construction all contribute to the problem as pre-determined by other participants here on this thread. No doubt! Tony, getting back to the original information shared. The "Silicone" you used to secure the track to the roadbed takes an exorbitant amount of time to dry to a cure and still remains in a liguid state or elastomeric... for it's duration. This will actually move the track around. Like sitting on a floating surface. This is why I use a CA (cyanoacrylate) to CYA. Once it sets up it takes a chisel to remove it. Me thinks the silicone might be the base cause of your problem. I never leave a open gap in the rail during construction. Of course I lay track on the hottest day possible and expect it to contract or pull back. I prefer to cut in the gaps, as needed. I usually cut in my gaps at about six foot intervals and this generally coincides with the lengths of my blocks. However, I've heard of guys that use a sliding rail joiner to allow for the contraction and expansion with some success. I'm sure this is what you were going for. At the Anaheim NMRA Convention, I learned about a new glue that may change my way of thinking as to construction of my layouts. "X1". Totally amazing stuff. You might want to check this out. No glued or stuck together fingers. It will adhere cork road bed to any wood surface, foam surface and foam to foam. Dries almost immediately but with enough time to move or straighten out a kink. Have you heard about this? Just something to think about.
I went back and looked at the damage. It seems that there are gaps only on the tracks that cross modules. Most the connections are right over the joint of the wood modules. I did this so it could be portable when I split the modules to move. I think I can insert some C55 straight sections in between to fix the problem. I have several friends that have used the silicon with no problems. I think the wood is the culprit and everything is going to dry up around here in about a month. I'll may just wait to see if it contracts again. I am also half tempted to just rip the layout down and keep the modules until we move again.
Tony - that's how my modules are connected and it works great. Here's a post with some details: http://www.trainboard.com/grapevine/showthread.php?p=63992&highlight=calipers#post63992 Good luck.
Here's more info. Their website is quite good and informative. X1 Instant Adhesive - Foam Safe Water Based Instant Gluing for Model Planes & Trains - Purimco Products Check out the trains video The product is quite expense. These prices are for small ounces. http://www.hobbylinc.com/prods/rg_pup.htm
