Looking at the layouts on the N scale forum. I notice that most of the layout are built-up rigid foam on plywood. I was watch a series of YouTube videos created by a local HO club. They used 2" strips of homesote laid on edge on L grid bench work as road bed. To me a newbie, the homesote road bed allow you to add vertical dimension, gaping ravines, deep river beds etc all while keeping the track level. So, I was wondering way N scaler's prefer rigid foam?
The argument for foam... Good question. I can think of a several reasons... I'm sure others can chip in with additional ones... * N scale is compact enough to make shelf layouts feasible, and using rigid foam (directly mounted on wall brackets) keeps the weight down. * Compared to plywood or homosote, rigid foam is easy to work with (light, easily transported, easy to cut) * Interesting topography is indeed possible by positioning track on solid foam risers above the rigid 2" foam substrate * Homosote is a bear to work with... creates a mini-dust storm when cut * Rigid foam is dimensionally stable under varying humidity conditions * Rigid foam is easily carved to create interesting scenery
Bryan has hit the best points to be made. Homasote still works, but the newer technology of rigid foam is fast replacing it. Many N scalers who feel a need to go non-foam, are doing good old plywood. Others like to use sawn strips of one eighth inch masonite, on edge, laminated: Which is far better than homasote any day. My opinion is opt for other than homasote. I've not employed it in ages, that day is done and long gone.
I know I am repeating myself about my own experience with homasote and why I prefer rigid extruded polystyrene foam. Even though the n-scale club I joined in the mid 1970s used homasote on a wood frame, I found at least in Minnesota in a heated basement, it was not stable and my flex track warped with instability of the homasote. I replaced it with plywood and used cork roadbed about 25 years. Now I am using rigid 2" extruded polystyrene foam over plywood since 2006. I am using Kato Unitrack. I think the plywood is an overkill and a frame of plywood would be excellent support. I am not planning on a shelf layout for the future; want access from all sides, thus island style.
Sometimes modelers get "stuck" on using a particular material or technique; unfortunately, doing so may lead one to overlook newer materials. Sometimes the resistance to change can result in a stubborn refusal to acknowledge a better method. Or, a modeler may be predisposed to their choice owing to their skill set. The fact is, rigid foam has been gradually replacing Homasote and other wood-based materials for the last couple of decades. Some modelers now use rigid foam exclusively, with no plywood underlayment, and enjoy all of the benefits noted previously by Bryan. For myself, I've long abandoned any wood materials for layout-building, and use only foam. Having said that, if something better should emerge, I'll be anxious to try it.
Even with paint sealing, if you have variations in heat and humidity, homasote can eventually warp just enough that it will be hard to live with in N scale. Homasote is also getting hard to find, being replaced by extruded styrofoam. If you live in warmer areas, the foam may be hard to find close to home, but the homasote will probably be near impossible to find. The trend is toward lighter building techniques overall. You won't need 2x4 framing anymore to support a 1/2" plywood base with Hydrocal/plaster mountains on top. It means you can't stand on your layout to fiddle with a vent or lighting, but most people try not to do that anyway. With current methods, you can build in a moveable section to access something that will need servicing, like a furnace. See, for example, what the Free-moN guys have been doing. And you can move the section(s) by yourself instead of calling in all the neighbors.
I was fortunate to read about the use of extruded polystyrene foam to build scenery such as hills and ridges on a layout, thus I never used the "hydrocal or plaster" for topographical features. I also discovered light-weight spackling and use a thin coat of it to fill voids and created desired texture on the foam surface. The result is that I have very light weight ridges that can be moved and re-used. For about 25 years, I recycle these elements on my home layouts.
A drawback of the foam is that it does not rebound. So if used as subroadbed be careful not to compress it or you will end up with a roller coaster rather than a model railroad. Don't put an elbow on it or clap it without spreading the clamp pressure considerably. Adding a layer of paint with scenery sealed with white glue creates a safer crust that is much less likely to leave impressions that the unprotected foam would. I still like the plywood subroadbed for the track with cork, but will use the foam for scenery.
This is true, but the stuff is still pretty darned tough. I dropped a hammer from the ceiling squarely on the track below, and aside from a slight ding in the rail itself (which was easily repaired), the foam showed no signs of having been deformed.
I used foam just as I would plywood. Here is a four foot wide peninsula raised above an 18 inch wide cabinet.
I Like rigid foam because unlike plywood or homostate it will not warp so if you have laid track in all different weather conditions you don't have to worry about your track as much. https://sites.google.com/site/kensengineandsteamrepair/ Where all you DC and DCC Needs are!
