Layout Materials

Model Railroader Layouts and layout building
1

I’m building my first serious layout (in retirement) and have received some confusing information on table top materials. My layout will be HO on a 4 x 8 table. I have made the basic table of plywood supported by L-girders for stiffness.

Now, I’ve seen recommendations for Homosote, polystyrene, and polyurethane plus just use the bare plywood. I’ve only been able to find polystyrene but I believe that it will be a mess to work with (like those crumbly plastic cups that spew tiny beads all over the place).

Question: where can I find Homosote and/or polyurethene? My local Home Depots and Lowes don’t carry anything but polystyrene, and little of that. Does anyone have recommendations as to where I can find some of the other materials (plywood’s a no brainer) and why use one kind of material over the other? I plan to have some hills and below grade river channels.

2

Hi. To keep your construction as light as possible, consider using 2" “extruded” foam. Dow Chem makes what they call “styrospan”, and it is blue. If you live in a temperate climate, you will find it at the builder’s supply centres. Plywood would be the next best in terms of overall efficiency of purpose. A sheet of 5/8" supported on 20" centres should be fine.

Homosote is susceptible to changes in dimension due to ambient humidity. It can be sealed, but it is also necessary to support it more than the plywood, if I have my facts straight. Either way, it means more $ for sealant and for supporting material.

If you use extruded foam, you can carve it for terrain, and stack pieces for topography. It will be noisy unless you use softer roadbed, such as cork or AMI or Woodland Scenics foam-types.

3

I suggest the Woodland Scenics foam-type roadbed. Even on plywood, it doies a good job.

4

I use the pink 2-inch foam. I think it’s made by Owens-Corning. It’s the same stuff as Dow makes, but just a different color. I got mine at Home Depot. Forum members from the Southwest report that this stuff is hard to find there, because insulation is less of a factor than it is in the frozen North.

I use it without any plywood at all. I’ve just got a frame made of 1x4’s, with rafters of 1x3 every 16 inches. The foam easily spans the 16-inches, and could probably go a lot further. It’s very stiff, and is not significantly affected by temperature and humidity.

5

Welcome to the forum. Are you looking for a material to use as a roadbed or do you want to cover the entire plywood with foam/ homasote to have the ability to do scenery contours (cut away areas for below track drainage ponds etc). If you need just roadbed you can use cork, homasote/ Homabed, Woodland Scenics and other materials for this. I believe the confusion is that recently layouts are being built with foam, usually 2" like MisterBeasley mentioned. The one thing with using foam, is you still need a roadbed material and this and the track will have to be secured with Liquid Nails for foam or latex caulking. The old method of track nails is out. They have nothing to hold to.
Give us some more info, this will help in pointing you in the right direction. Regardless of method, there are many on the forum that can help.
Bob K.

6

Robert Knapp: I’m going to use the foam on top of the existing plywood so that I can cut away for suppressed areas, add hills, etc. I’m in the southwest (So. Calif.) so most extruded foam is hard to find as noted above by “Mister Beasley.” I have managed to locate some 1" to 1.5" polystyrene (the kind with tiny balls of plastic) and I’ll have to use this if no other material like polyurethane is around - maybe use a hot-wire rig to cut and shape to minimize debris.

There was a recent MR issue that showed how to use a double-sided tape to lay the roadbed, so I may just use that on top of the foam, as you suggest.

Another task that I will have is to convert all my engines to DCC. I’ve had a little help from Digitrax via email. Any suggestions here? DCC is truly a no-brainer vs DC. While I was thinking about thinking about my retirement project and before I knew about DCC, I thought that a system based on radio controls for model airplanes would be neat but DCC is a lot better.

7

To help keep the mess to a minimum when you are cutting this stuff, place a box fan pointing AWAY from the work area, with a fiberglass furnace filter on the suction side, this will stay on the side of the fan when the fan is running. The air from the room will be pulled through the filter, and the foam debris will be caught by the filter, this also works with sawdust and other light materials, such as overspray from airbrushing or spraypainting. When you are done sculpting, sanding, carving and such on the foam, give it a good coat or two of some basic white latex paint, this will cover the original color, give you a good base for any other colors or finishes you decide to use, and help keep you from having a constant supply of little foam pills everyplace.

8

I used 1" extruded foam on my plywood, but planned on building contours and elevation using 2" foam scraps and hard shell with plaster casts. With the plwood you don’t need the support, but you may want the depth for your scenery.

9

Try to avoid polystyrene. The little beads are a mess, and they stick to everything. I have 1" blue foam [built up to several thicknesses in places for contours] glued to 3/8" plywood. I did not glue the track or roadbed down; I used Atlas track nails. They will hold in the foam long enough to ballast, and when the ballast is dry I pull the nails. The ballast holds the cork and track in place on the foam. After carving the foam to a rough shape, I cover it with Sculptamold for final scenic details.

10

[#welcome][#welcome][#welcome]
Silly advice but real…
Go from where you are unless you find that it doesn’t work.
From what you say you’ve made a good start.
You will always find that there are other ways of achieving the same end. On 4x8 you only have room to try some of them.
Usually one or two methods will do anyway. They don’t have to be perfect… and, if you tried a different two, they’d probably be no better over all:- just different.
It’s like house maintenance:- you’ll always find a new product and someone who will tell you “never use that” or “I could do it better by…”
The thing is to choosse the way you are going to do it, pick up the good tips for that (like using the fan and filter) and ENJOY YOURSELF… it won’t be long before you can tell the newbies “do it this way” or “NEVER do that”!
It’s all part of the fun.

You’ve got one thing right…
You’ve got on this forum! [:P][:P][:P]

Next clever step is to do a lot of checking back through old threads… Joe Fugate’s stuff is good and there’s a load of other good guys.

Have fun! [(-D]

11

Then again…
My personal preference is to lay a sound, flat roadbed surface and to keep as little material between that and the track as possible. That way I don’t add complications between the original good surface and the rail.
Personally I don’t mind some track noise… running old brass diesels the thrum is way cheaper than all the modern high-tech /micro chip sound technology… and it’s always there without programming[:p]
Again, I don’t like double sided tape… it’s never even/smooth… and (in my view) you don’t need it. I’ve had no problems with track pinned as often as experience shows is needed (more frequently on curves).
i could go on but (as you will realise) this is just one of many sets of prefernces.

You might do well to post the DCC stuff as a seperate question.

have fun [8D]

12

You already have a table, plywood over L Girder, so my recommendaqtion is to cut the plywood in rectangular sections where your river will go, and fill that area only, in with foam. Like a bathtub with square corners, filled with foam carved to make your river.

Foam can be noisy under track, and won’t take nails, you already have a flat surface to work on, no need for the extra expense. Clearly, this won’t work well if large parts of your layout will include below grade scenery, but if it’s just one river, you can easily spend weeks messing around with hybrid benchwork schemes and in the end, wish you had taken the simple and obvious path of least resistence.

With a solid table in place, you can use 1/4 inch luan plywood for roadbed, it holds track nails and rail spikes well, it is inexpensive, and it can easily be cut to a 45 degree bevel to simulate embankment edges with a jigsaw and a fine tooth blade. Strike your lines, both curved and straight before cutting the luan, but don’t be too careful following them with the jigsaw, except at the ends where you have to match to the next piece. Gravel doesn’t pour in straight lines.

Try to avoid places where rail joints occur directly over roadbed joints, and in any event, a belt sander or flat sanding block with 60 or 80 grit paper across your roadbed joints before laying track will save you at lot of detailed fiddling later on.

Take the time and construct extra wide pieces of roadbed under turnouts, so that the turnout, and at least three inches of all three pieces of track attached to it rest on a single piece of roadbed.

Be careful to buy all your roadbed at one time and place, minor variations in thickness from lot to lot can cause you a lot of problems later on.

13

I wouldn’t use a hot knife on polystyrene beadboard - gives off nasty fumes. And carving is messier in my opinion than carving extruded foam (the dense pink, blue or green insulation sheets).

I’ve used plywood and cork, plywood and Homosote, foam and cork and now foam and Woodland Scenics foam roadbed. I’m convinced foam and WS is best for my application.

Since you already have a plywood deck, I’d use cork or WS foam on that and whatever is handy and cheap (polystrene beadboard or “peanuts”, extruded foam, cardboard strips, etc) to build up contours. As jeffers_mz said, cut the plywood for any lower elevations like streambeds.

The MR article I last saw about tape used “topper tape” for sealing tops to pickup trucks. An earlier one used double sided mounting tape but I’ve never tried either.

I agree that there isn’t a single “right” way to do it. I’ve even seen articles where they used a plywood - foam - plywood - cork sandwich, although that seems like overkill to me.

14

Just in case you don’t think of it (until too late)…
If you cut down through your top surface to insert riverbed… be careful about weakening the strength of the overall structure… you don’t want your river to become a neat hinge line as the whole thing buckles (it’s SO embarrassing!).
You can still cut down but remember to add bracing plates to the frame. You can do this by adding deeper ply sections or (if you can’t drop lower) by bracing with steel plates each side bolted through. Basically it’s the same.
You probably known this… I’d just hate you to find it out the wrong way![:O]

Have fun! [:P]

15

Why this fixation with plywood, foam or whatever roadbed? I use 1/4 straight edge cut trim molding laid on edge to form a spline, back in the day we used the same technique with Redwood splines…I handlay my code 83 rail, so a 1/4 lunan plywood surface glued to the spline provides the hold necessary for spikes. I don’t get caught up the noise factor.

dave

16

This is where “L” girder construction come in handy. I have dropped a riverbed right down to plywood mounted on the L girders. This can be 8-10" depending on the risers. Of course anything deeper requires major surgery and redesign of the benchwork.
Bob K.