So at 8:15 this morning with the wife just reversing out of the driveway and slip sliding down an icy 1st Street, I disappeared into the basement. With nothing more than a craft knife, a couple of sheets of 3/4"(approx) expanded white polystyrene sheet and some Loctite Powergrab adhesive...
Slicing up the styrene sheet is so much easier than working with wood. Not to mention a darned sight quieter. Ten minutes later I had one of the sheets cut up into strips for the framing and could set about the gluing. A word about slicing the polystyrene sheet up. I find that if you cut it like you would any other material with a knife you'll end up blunting the blades quite quickly.
For slicing the strips up I used one of those knives that have the long blades that you can snap the end off when it blunts. I extend the blade out to its fullest length and use it like a saw. Only if I need to make a second pass do I use a cutting motion. That way you make a better use of the blade and can make a much cleaner cut with very few of those annoying white polystyrene beads around to get in your clothes and hair.
So there you go after no more than 10 minutes of cutting I had all the strips of framing I needed cut up and very little mess to boot.
Next, the gluing together. I used some Loctite Powergrab that I had lying around. It had been lying around for several years so a couple of days before I glued up some offcuts of polystyrene sheet to see if it still worked. It did. So it was a very simple task to glue the whole lot together to make a model railway baseboard, as you can see from this picture.