Plywood vs. Humidity

Discussion in 'Modular Layout Forum' started by riverotter, Jun 20, 2008.

  1. riverotter

    riverotter Midwest Alliance Rail Sys

    Free-Mo Modules from HCDs?

    This thread has really generated a lot of ideas! I started it off asking for opinions about various ways of beating the variable temperature/humidity situation I experience here in the "middle Midwest" (where I've only lived for 3-1/2 years) and look where it has gotten! Please keep up the superb contributions!

    I have been selling off some of my "surplus" equipment (a lot of it still in its original boxes!) to raise money to replace the warping hardboard I had used previously in the around-the-walls sections of my new layout in favor of hollow-core door modules/dominoes.

    Now I'm looking at the reconstruction of these sections of the layout from a Free-Mo perspective and wondering: is there anything in the Free-Mo standards that would discourage me from building Free-Mo modules using HCDs?
  2. pgandw

    pgandw Active Member


    The key to Free-mo and the most important part in linking modules is the end plate. If lumber is used for the end plate (no rules against other materials), the end plate needs to be 3/4" thick (plywood strongly preferred for stability), 6" in vertical dimension, and 24" or 26" in wide. It must be held vertical and perpendicular to the track center line against C clamp pressure by the rest of the module frame.

    I'm not sure how you would attach a suitable end plate to a HCD that would maintain the true 90 degree angles in all axis under C clamp pressure. Obviously, some form of gussets would be required, but would the HCD be strong enough in tension to maintain the fastenings? Another point - having easily adjustable legs is key to reducing stress on the module frame when setting up on less than perfectly level floors (most venues) or when the adjoining module owner's craftsmanship is not quite as perfect as yours. :wink:
  3. I'm drawing up an aluminum frame to FREEMO standards - I'll post some drawings soon. I'm also looking into some more ideas on the adjustable legs.
  4. railwaybob

    railwaybob Member

    The "Free-mo" concept follows some pretty strict standards principally for interconnectivity of modules. The idea here is that members in a club or in different clubs individually own modules. They all get together several times a year (in my case about 6-8 times a year), bring their modules, and assemble the modules into the largest honking layout you have ever seen. The plan is pre-determined by one of the club members as all modules are on CAD software so it's a simple matter of drag-and-drop to come up with a layout plan within the limits of the hall space available and within the creativity of the layout designer. For many clubs, modules can be single-track (sometimes referred to as Free-mo), double-track (the more popular version is N-Trak), or both (sometimes referred to as transition modules that go from double-track to single-track).

    This doesn't mean, however, that one can't build a layout using the modular concept. We all, no doubt, have been faced with the situation where we have a beautifully scenicked layout that operates very nicely, only to have to tear it all down when we move to another place. A lot of work goes into the garbage container. One way to avoid this is to build the layout in modules. I first saw this concept explained in an article by Dave Frary in Model Railroader some decades ago. The concept has since evolved into things like Free-mo, N-Trak, HO-Trak, and even G-Trak. The advent of DCC has made it even easier to build a layout in modular fashion.

    Whether one uses hard-core doors, plywood frames, knotty pine, or even aluminum is irrelevant when it comes to a home modular layout as there is no probability that these modules will ever be connected to someone else's modules. So, what works for me, might not work for someone else.

    The idea here is to come up with a number of ideas that anyone can select, based on their comfort level in working with the materials that are available.

    The idea of HCDs seems to be an interesting one and one that seems to be in great use. Perhaps someone can do up some webpages on the techniques that they use in making a modular layout using HCDs.

    While the Free-mo standard specifies a 6" endplate, we've had very good success with a 4" endplate. I've even used a 3½" endplate (4"x 1")If the endplate is properly braced with corner gussets, the "stresses" of C-clamps have no impact on the endplate. I've used both ¾" pine (1"x 5") and ¾"plywood and there's no difference between the two. It all depends on what one is comfortable with.

    Just a few thoughts on the matter.

    Bob M.
  5. Here's what I've come up with as far as creating a Freemo compliant module with an aluminum frame for minimal cost (that's minimal cost for an aluminum frame, not necessarily compared to other techniques / materials).

    The endplate is 1/8" aluminum plate reinforced with a 1"x1/8" flatbar welded inside at 'frame level' (effectively making it a very large T shape, as discussed previously). The plate is 6" high, per Freemo standards.

    The aluminum frame is narrower than the Freemo standard, allowing for the thickness of fascia material - the module builder's choice; could be hardboard, masonite, acrylic, more aluminum, etc. I'd personally go with masonite here - it's easy to cut to any shape to match scenery profile, and drill and file holes for throttle plugs, switch controls, etc.

    The foam sits on the 1-1/2"x1-1/2"x1/8" aluminum channels, which are now turned downward, and also act as a mounting surface for the fascia. A 1" aluminum angle supports the center, and two more pieces of flat bar support either side. The supports' positions can be adjusted to allow for placement of below the table accessories, such as switch motors, if needed.

    The location of the main side channels is determined by scenery needs. I imagine 2" foam would be typical, but the could be mounted lower and the foam layered if features like valleys were desired, or moved upward if thinner foam or some other material is used.

    I haven't had time to look into the legs much, but seem to remember reading an article a few years ago about using folding banquet table legs on modules - they fold flat (in the module I've drawn, would fold into the bottom of the module), are adjustable in 1" increments allowing for the height range from min. to max. railhead allowed by Freemo, have swivel adjustment feet on the bottoms for final adjustment, don't weigh a lot, and are pretty cheap - about $25 a pair on the net. In the article I read, the guys added a length of pipe to each leg to bring them up to minimum height.



    Attached Files:

  6. CN_Fan

    CN_Fan New Member


  7. lamasa11

    lamasa11 New Member

    I live in Texas, The major concern is heat and Humidity. I use 1/2 inch obo plywood.
    This is a marine type plywood that sign boards are used for. I glue and screw two
    sections together making the size of 2' x 8' by 1" thick. The next step is to lay the roadbed. I use scottboard siding. This stuff is used for wall sheathing and comes in sheets of 50" wide by 9' long 1/4 inch thick. You can cookie cut it, make curves, any track design you want. After laying the roadbed. This stuff can be nailed or glued or both. Paint the entire board gray inculding the roadbed, then spread flitered dirt covering everything except the roadbed. While the paint is wet. This not only seals the plywood and the roadbed, it also provide a base for ground cover.
    the table top and the roadbed. This will solve the humidity problem.
  8. railwaybob

    railwaybob Member

    Gosh, it's been a long time since I've been here!!! Since then, I redid my module construction techniques. You can find them on my blog at
    And yes, I belong to OVAR, HOTRAK, BRS, ORHC, and the G-Men.

    Bob M.
  9. Bill Nelson

    Bill Nelson Well-Known Member

    ready to try something!

    I am getting ready to make a small HOn3 portable, to show off my Blackstone C-19 with dcc and sound. I have some 2 inch Styrofoam that I will use to make a lightweight base, and to cut pieces to make my elevations. I have some high quality 1/8 inch plywood, that was once a soffit above a set of cabinets that was removed dirring a kitchen remodeling project . The plywood is unwarped in spite of being in place in a kitchen in a 130 year old hose for 20 years or so, and then being stored in a slightly damp garage for another eight or nine years.

    I'm going to cut the former sofit material into cookie cutter roadbed. after I do that I will paint it on all sides before bonding it to the foam, hoping that this will help minimize warping. I'm not sure if I will use any roadbed; I usually like to build on homasote or homa-bed (comercially milled homasote) but unlike most of my project There will be no hand laid track (excepting bridges), and keeping weight down is a priority , so roadbed may not be used.

    on a side note; A lot of my recent benchwork has been on upper levels. I have been making the upper level benchwork carefully with cavities to hold florescent lighting for the lower levels. I have found that painting the lumber used to make the upper level benchwork white, helps to reflect more of the light down to the lower level. so there is another advantage to painting wood before it is used. Good lighting really helps a layout.

    Bill Nelson
  10. Bill Nelson

    Bill Nelson Well-Known Member

    I started my Hon3 minni layout. a photo of it's Styrofoam base, and the painted 1/8 th inch plywood subroadbed is over in the narrow gauge section.

    here is a link.

    I was testing a procedure for painting old faded aluminum siding, so I used some extra high quality exterior latex to paint both sides of the road bed. I will probably get some cheap interior latex paint mixed up gray to paint the road bed foam and everything else as I start to build up some foam land mass.

    Bill Nelson

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