Soft body, hard shell
No, this is not a description of the average railway modeller, but a reference to the baseboards for my 2010 challenge layout "The depot". The scenic section of this GWR micro- layout is to be housed within an Ikea "Snackbox". This plywood shell now houses a "soft" self-contained baseboard, made from 10mm foamboard and measuring 35.2 x 54.1 cms (13.9 x 21.3 in). This serves to raise the scenic section, and provides room for electrics etc underneath. I'll add a thin fascia to the front in due course.
The foamboard structure slides in and out of the Snackbox. This should make it simple to work on from all sides during construction, and will make it easier to take photos from tricky angles when the layout is complete.
The simple bracing, which strictly speaking I could probably have done without, given the thickness and small dimensions. The entire foamboard structure weighs in at 250 grams.
The 10mm board seen next to a 5mm example and showing the sandwich structure of this material. The idea of using foamboard for lightweight baseboard construction is of course quite well tested by now, eg on Chris Nevard's superb Catcott Burtle. There was also the Kappa Board layout which even made do without the plywood shell.
So far I have used my X-acto knife as the main means of cutting the foamboard, although I hear that a scalpel may be better. With the thickness used here I do occasionally have problems keeping the end profiles exactly at 90 degrees. Checking the web I found these specialist foamboard cutting tools that look tempting but also rather expensive, so I think I'll keep at it and learn it the old-fashioned way :-)