The need was for super-light weight & to fit the boot of my small family car (Diatsu Sirion). With various off-cuts of MDF and plywood I came up with the estimate that a 'coffin' 3' x 1' x 1' would nicely slide into the boot. Thus was the size of the layout fixed

Next was the basic construction. "Super-lightweight" really ruled out the good old 2" x 1" and chipboard but I ruled those out many years ago. 3mm ply with 1" x 1/2" PAR built up in box girder was also likely to be too heavy; tried that in the past to.

What about all that 4mm foam board I had cadged from the local super market - there was still sheets of the stuff? Certainly light but to give firmness and anti-twist it would need some sort of egg box construction. Probably too complicated.

What about expanded polystyrene, - my caravan was built with a sandwich of foam between ply on the inside and aluminium on the outside, a very strong, anti-twist construction.

With the practical experience of heat-insulating ' Honley Tank' & the rest of the garage/railway room using what I thought was expanded polystyrene, this material had been in my mind as possible baseboard material for some good few years. Then low and behold two articles about the stuff in MRJ.

With those read and absorbed and some www. searching I came up with the knowledge that the material was actually extruded polystyrene not "expanded", that it was available in many thicknesses and sheet sizes, and that it was not so cheap as I had thought

A visit to our local DIY store (the one with a B and a Q in its name proved that they sold individual sheets 1 metre long by 1/2 metre wide and 50mm thick. One sheet weighed only a little more than nothing and because it is intended as heat insulation, the price is subsidised.

OK!the basis of the boards would be extruded polystyrene but the ends and sides would need some protection because this is fairly crumbly stuff. MDF suggested itself for the ends- mainly because I have loads of off-cuts in stock. Also the 10mm thick stuff would allow for sinking in of pattern makers dowels to ensure that the two boards would always re-align correctly and two bits each about 70mm x 300mm would add little to overall weight.

Also in plentiful stock was 4mm ply; so the protective sides became 1000mm x 70mm x 4mm, again not much additional weight. With four pieces of pine cut to 150 x 28 x 21, and a pair of 'pasteboard' hinges I had two baseboards nicely hinged together measuring 1000 x 300 x 300 when folded and 2000 x 300 x 150 when unfolded.

There was need to hold the folded pair in the 'coffin' shape for travelling or storage and this became a further hinged extension made from strip timber and some of the ex-supermarket foam board. The usable baseboard length then became about 2250mm or 2&1/4 metres if you prefer