I'm working on a project called Pedal Fighter, which is a MIDI foot controller inspired by the MIDI Fighter project. I'm in the very early stages of work on this, and since I don't know much about how I want the final button layout to look I'm planning on iterating a bit on the physical properties of the device.
Normally, when I'm doing software I plan on doing some prototypes or at least many iterations on the idea before the final form starts to take place. But, how to do this in the physical world? We are getting close to having cheap 3d printing, but I'm thinking even more low tech.
I had some notions in the past about doing cardboard forms and using epoxy-over cardboard as a prototyping material. Now I'm thinking even cheaper and easier than that. There are 3 components to this method - MDF (medium density fiberboard), pine furring strips, and #6 wood screws.
The idea is to make enough of the surface panel available using MDF and the structural members will be spars formed from the furring strips. The MDF is mounted to the furring strips using #6 wood screws, which are really cheap. Even from Home Depot, a box of 100 us under 4USD.
I haven't gotten too fancy with this method yet, but I'm already thinking of ways that I can expand on this technique.
For example joining two furring strips together to form a wider member can be done by cutting a bit of MDF and using it to join the two (or more) strips together into a structural member. If more strength is needed, we can use MDF panels on both sides.
If the panel needs to take more load, we can add more furring strips underneath to bolster the surface. If we can't spare the room needed for additional spars, we could use 1/4" MDF rather than 1/8". The thicker MDF is much stiffer but costs 50% more.
I'm thinking of some other ways of doing cheap prototyping of enclosures and boxes for projects. Somehow I don't like the idea of buying a generic black plastic or polished aluminum box for each project. I like feeling like I can drill holes all over the prototype and move things around without destroying a 15USD project box. At the end, when it is time to finalize the design, we can just cut a new panel from MDF and replace the one that looks like swiss cheese.
The only problem is that MDF looks ugly. I'm going to have to see how it paints up before I pass a verdict on looks. I'm not sure if a prototype made from MDF will be taken seriously if you need to present something in a design meeting.
I'm going to explore a few other build methods, including using foam board and aluminum/steel extrusions for things that have to be really light or rigid, or both.