Most modules use wood as the primary framing material. The obvious advantages of wood are:
- Ease of fabrication
It also has two disadvantages that I find overwhelming:
- Environmental stability
While wood is readily available, easy to work with, and affordable my feeling is that wood is too heavy to be an ideal material for module construction and its environmental stability can cause issues. I live in Arizona, which is a semi-arid and warm (some would say hot) environment. Many of the friends I have in the modular world live in Ontario, an environment that is both wetter and cooler than Arizona.
If we built interface plates for our modules out of wood, me in Arizona, and them in Ontario, even if we were exact in our measurements, our interface plates would not be exactly the same when we met to build a temporary layout. Wood expands, contracts, warps, dries out, and is attacked by insects.
Because of this, I am looking into alternative materials and methods of constructing the frame work for modules.
High-Density foam is already used in place of plywood as the top plate of many, if not most, modules today. I have seen plans that used foam for the frame as well by utilizing pieces of foam cut like 1x2s or 1x3s and formed into an L-girder arrangement similar to the traditional wooden L-girder frame work. High-density foam is lightweight but expensive. I am not sure of its dimensional stability or its environmental stability but it is a definite contender for use beyond just the top plate and scenic elements.
I have also seen several designs based on Luan plywood but most of them require good woodworking skills, which may make it hard for newcomers to achieve adequate results. Still Luan plywood is readily available, relatively lightweight and strong.
Bamboo is both lightweight and incredibly strong. It is used for scaffolding in much of Asia, so it certainly could have uses in modular designs.
Balsa, while a wood, is the lightest commercial wood in the world. Balsa is both stiff and dense with bending strength that exceeds most pines and spruces. I have never seen Balsa mentioned for modules. It is worthy of further investigation especially as part of a composite sandwich with fiberglass or kevlar. There is a reason it is heavily used in both the model and experimental aircraft fields.
Thick-wall PVC is already in use for some leg assemblies but it could be used much like bamboo.
Fiberglass is not hard to work with, is fairly lightweight and can be very strong. It has the advantage of supporting complex curves, which could extend the concept of modules in several ways. In addition to fiberglass, there are a number of other composites that consist of reinforcement and resin. Kevlar, Nomex, and Carbon Fiber to name just three.
Aluminum is also used for some legs and occasionally for side frames. It is strong, lightweight, and machinable.