We don't need no stinking foamular, styrofoam or any such nonsense. LOL I'm so old school it sucks. The only reason I'd have any foam on the layout is for the scenery and to insulate the walls. My feline friends like the cork road bed as a scratching post. They'd tear through the foam in a heart beat and then where would I be?
The process for extruding polystyrene was finalized by Dow in 1941, so Styrofoam is eight years older than I am and I'm 64. How "old school" are you Rick???? Cheerio! Bob Gilmore
I'm a complete "foamer" convert. After building my White River and Northern from 100% extruded polystyrene--roadbed, scenery, the works--I would not go back to using any form of wood product in any future layout. Noise becomes a non-issue once scenery is done, and the luxury of being able to make alterations with ease--changing the course of mighty mainlines with only a packing knife--just can't be beat.
On my last layout, I used Homasote. Most was glued or track-nailed down. However, the last section I was working on was a coal branch. I placed the Homasote down on a heavy-grade, 3M double sided tape. It was noticeably more sound "friendly" than the balance of my layout using nails and/or glue. This all on 3/4" pine plywood. I plan on repeating this as I build my next layout.
I've read that nails transfer sound down to the framework. I imagine that the double sided tape is a great sound insulator. I'm building an N scale layout on a HCD and I've noticed that the sound from the locos goes down into the hollow center of the door and reverberates and gets louder, kind of the way a good sized trunk in a car is great for a car stereo.
I've used 18 to 48 inch deep/wide shelves of 1/2 inch Homasote on 1/2 inch plywood or 1/2 inch OSB panels (waferboard?, woodchip board?) resting on stringers supported by L-girder benchwork. Homasote panels on OSB panels seem to be a little more quiet than on plywood panels, but that might be because my Homasote and OSB panels were usually cut so that the ends of any two Homasote pieces are staggered to fall 1/2 to 2, 3, or 4 feet from the abutting of any two OSB panel ends (but seams between the plywood panels had been very close to seams between the Homasote panels). Also, I've only used one or 2 screws to hold any Homasote piece to any OSB panel (e.g., 8 foot and 4 foot sections of Homasote might be connected to 4 foot and 8 foot sections of OSB panels with just 5 or 6 screws driven through the panels into stringers under the 12 foot long shelf); but, when I used plywood, I secured the Homasote and plywood with multiple screws and only staggered the seams by an inch or so. As a result, like with the 2-sided tape above, the sound of shelf sections connected with few screws may have been less than the sound in shelf sections connected with many screws. As others have mentioned, I've also noticed more sound reduction in those areas where I've added ballast and scenery. For what it's worth, Homasote is a paper product and, as such, easily picks up moisture from the air. I think the Homasote was quieter in the times of higher humidity (...??maybe because the higher moisture content functionally increased the density of the Homasote??), but my high and low humidity comparisons were made several years ago during different seasons and, for the past few years, I've been minimizing fluctuations in my trainroom humidity levels with dehumidifiers and humidifiers...so my recollection of comparative sound levels from past summers and winters may not be too reliable.
I was just going to start another thread today over Homasote..But I happened onto this one and so will present it here instead > I've never used homasote (yet) ..But I keep wondering, why do those who do build 1/2 inch ply subroadbed first ? Unless we plan to get up and walk on layout couldn't homasote alone be placed (glued/screwed/nailed) right to the wood frame and/or risers ? Since it's dense enough for spikes, drillable, sawable, sound absorbing, shapable ( drainage ditches and such), why not skip the plywood ? Maybe just double up on risers for rigidety...no ? Maybe something to do with a problem butting 3-4 inch ends together along right of way ?
I am building my n scale layout directly on Homasote with risers spaced approximately every 16". I was able to cut the track bed from a single 4x8 sheet and do not have any joints. The Homasote does have some warp and sag between risers and for the most part I like the natural undulation. In a couple places I built up the roadbed with some shims to reduce some of the sag. Another reason I like using just Homasote without any plywood base is ease of mounting under table switch machines. The machines (NJI twin coil on Rix, Peco twin coil, Tortoise) mount directly under the the points and the throw rod only has to penetrate 1/2" of material. If I were going to build another layout I would use the exact same method. My biggest problem is where a switch machine is situated right over a riser. This situation requires the machine to be offset with some complicating linkages to effect motion. If you are using manual throws then no problem. Otherwise I would be more careful about moving the risers to clear space for the machines.
Homasote will slowly sag over time. Without complete support, humidity and gravity will cause it to sag, even across relatively short unsupported spans. This may not be evident for months or possibly years, but eventually it will happen, and it will take anything attached to it along for the ride.
Yes, but I was thinking : Build entire layout with homasote on risers. Then, when all the SRB pieces are in place (tangents,curves,yards), perhaps go back and add say, 1x2s to underside of homasote between risers, parallel with track, acting like spines to prevent most warping (narrow, 3/4" side of wood is of course up against Hsote)..Might be able to yellow-glue them in by letting glue get tacky first, and/or screws from above..Could be offset so not directly under track or left out or removed if blocking a switch machine. Probably would need to miter sections for running beneath curves..Just a thought I had lately about layout construction...This is maybe what I'd try if I were to tear down present one (open grid 1x4s, 1/2" ply SRB, cork).
I'm in very good shape to experience how Homasote holds up with time. I painted the entire Homasote road bed before gluing it to the risers in order to seal it somewhat. It's been two years and the sag has not increased by any noticeable amount and I am still happy with the result. I do not intend to add any additional support because it complicates access to the track structure.
Great to learn this about homasote..I agree about liking the slight warping..I'm by far no expert in this hobby, but I've always felt alot of MRRs have the main lines too perfect, hill and dale-wise..I always notice when driving across the 1:1 grade crossings how track dips and lifts for the mile or so up the track I can see..But I also realise how the model needs greater acuracy in order to stay on the rails; that the 1:1 is much more forgiving this way due to shear weight and truck construction/suspension..There are some videos showing outrageously twisty, bumpy spurs and train rocking and rolling through it at 5MPH..! If I were ever to rebuild I know what I'd do this time....
