After reading this months (August 2007) “Trains of Thought” it got me thinking about what type of base material I will use for my new basement layout. I had long planned on a modular approach with the typical 3/4" plywood and homasote/cork roadbed “topping”. Now I’m thinking about the same modular approach but using foam to replace the plywood, but still using homasote/cork roadbed. This concerns me since like Tony, I live in the NE portion of the US where the winters are dry and the summers are humid. A/C is not an immediate option in the train room and a humidifier will be a hastle to empty (no drains in the basement).
I’m know this idea is not new, but I’m wondering of those who used this technique is their layout and trackwork “stable”?
I haven’t picked up a copy of the August MR yet, so I haven’t read Tony’s Trains of Thought. Why would replacing the plywood with foam cause concerns over swelling/contracting? Foam is dimensionally stable, and won’t move due to swings in humidity. If you’re going to worry, worry while using plywood!
If you’re worried about the Homasote breaking away from the foam because IT will be moving due to humidity swings, don’t use it. These days, the ONLY reason I can think of to actually use the stuff is if you’re handlaying (and who does THAT any more?[:D] ) If you’re looking at using Homasote for sound-deadening properties, use SILICONE caulk between the benchwork and roadbed; it provides a nice, springy surface that will dampen most noise amplification.
Even though my club builds more on the traditional “L” girder and open grid method, I feel that utilizing the foam for smaller or modular layouts to be beneficial. Many have had great success with attaching/ gluing the foam directly to the benchwork instead of the way overkill of over 1/2" or 3/4" ply. Foam is not affected by temperature and humidity swings like that of plywood. I still would recommend placing the foam on at least 1/4" if you want a surface to mount switch machines and the like. I’m just not sold on the digging out and securing tortoises into the foam. This basically buries the switch machine under the turnout and you better hope that it works for a long time and never needs replacement. I would recommend that for securing track to use a cheap latex caulk (DAP Alex Plus) don’t use silicone. Latex will hold as well but not create any issues if gets on the ties and will also allow the glued ballast to hold. Ballast will not stick to a thin film of silicone and you risk getting the stuff all over the track and everything else as your hands can spread it everywhere.
Forgot to show the area that is done with stacked foam. It is done cookie cutter w/ 3/4" ply. The hillside is a stepped plywood base to save on the amount of foam.
This unfinished end is a more traditional “L” girder w/ wood spline, the scenery is plaster over wire screening
As a Homasote user - yes, I do handlay some to all of my track - I read the article with great interest. The article confirmed my experience - that changes in humidity has less effect on Homasote than on plywood.
Since my next layout is headed in the shelf/modular direction, at least for major parts, I want to see if I can reduce the weight of the shelf sections. However, the modeled terrain is much better suited to cookie cutter rather than flat foam or plywood - as other posters have pointed out. I need to find a foam thickness, that in combination with laminated 1/4" plywood will produce the desired rigidity for supports spaced 16", yet is bendable to my steep grades (4%-7%) with the same reasonable-length transitions that I achieve by bending 1/2" plywood. I suspect 1/2" or 1" foam laminated to the 1/4" ply will work well, but need to experiment.
I don’t use Homasote (or cork) as a structural element. It is simply there as a sound reducing surface, a way to obtain raised roadbed, and in the case of Homasote, provide a suitable spiking surface. Because foa
