Benchwork question


CbarM

HO all the way!
I am curious, with all the pics of benchwork I have seen, I notice alot of guys are laying strips of plywood about 3-4" wide on top of the framework, laying cork over that and then track on top. If the framework is lets say 18-24" wide, but you only have 1 strip of plywood for a subroadbed, how do you fill in the gap? Is this a better way if doing it then using plywood to cover the entire framework and using 1" foam overtop? The latter part seems like the easiest to me...
 
From what I have gathered, everyone does this differently. Really, I don't think there is a right and wrong. I went with an L-Girder design. Hindsight, I would have just built boxes with some joists and laid my 1/4" plywood on top of that. Here are some pictures of my benchwork design.
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Im not sure I understand the 'L girder' design. I guess there is no proper way, due to great variances of everyones preference and landscape ideas.
 
Here is how I fill in the space, which is really all your terrain. The strips of plywood are part of a method of sub-roadbed construction called 'cookie cutter' because you cut out the plywood in shapes that you need. Another method, which I used only once on my last layout, is called spline roadbed. You rip a sheet of masonite or 1/4" MDF into 5/16" strips as long as the sheet is long, and then you erect 1X2 risers to support the roadbed, they being fastened with screws to the cross-members or joists of your framing. You turn five or six strips on their sides and glue them together, but only three ply at a time so that you can bend them easily around a screw driven into the top of the risers and then clamp them with about 10 clamps. When they dry, you widen the roadbed with another two or three glued strips glued to them and clamped.

Anyway, note how I do my terrain: swatches of aluminium window screen hot-glued into the shape I want...the contours. How to achieve contours? Stuff soft things, maybe plastic shopping bags stuffed with crumpled newspapers and flyers, in behind the screen to force it into the contours you want. Over that, you slather a ground goop of plaster and vermiculite and Portland Cement. It hardens about 1" thick if I have done it right.

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Covered with the goop (camera is now turned about 90 deg to the right from the previous view):

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You really ought to consider adding the ground foam, which must be glued into place (I spray yellow wood glue, diluted, to which a drop or two of liquid dish soap has been added) while the goop is still drying. Once it is wet, being plaster based, it will absorb a ton of sprayed glue...so do it within about six to 20 hours.
 
As usual, Crandell has shown us the way it's done. Every model railroad I have seen that utilizes L-girder benchwork uses some variation of his terrain-creation method.

We are also seeing model railroads being constructed using extruded foam for sub-roadbed and terrain shapes. Sometimes, little or no "goop-like" material is used. OR, sometimes a layer of some sort of goop is applied as a top layer over the foam. OR, sometimes the raw foam serves as the top layer and is textured before paint and terrain materials are applied directly to the foam.

On this little corner of my layout, the rock texture is carved directly into blocks of foam.

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There are many options for creating terrain, depending on the construction methods you prefer.

- Jeff
 
The method I use is called open grid benchwork. I build rectangular frames the width of the benchwork and about 6 feet long. There are cross pieces every 18". The road bed is 1/2" plywood on 1x4 risers that elevate the plywood about 9" above the benchwork frame. I then use strips of cardboard cut about 1 inch wide to build a lattice and cover that with paper dipped in plaster to from a "hardshell" scenery.

using screen wire with plaster on it is a very old technique. I have model railroad how to books from the 1950's that use that technique. Of course, being that old they do recommend adding asbestos shorts into the plaster to make it stronger. Sometimes old advice isn't necessarily wise advice. :)

The problem with just plunking down a sheet of plywood is that it makes everything flat. Go look at a real railroad, there is as much below the tracks as there is above the tracks. Most railroads have some rise and fall. By using the risers the track can have custom grades and smooth transitions. I use that 9" of space between the benchwork and the roadbed on my layout to recess switch controls, car card boxes, etc into the fascia.
 
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