My Dad is ready to finish the track work on the Isle of Man test track so we dug out the board from the plastic box they live in and put them on his cleared desk. It became immediately clear that there was a problem - they wobbled.
Looking along the woodwork it was obvious that the wood had warped quite badly. One board had moved a few millimetres but the other was over a centimetre up in one corner. Both were quite useless for laying track. At first sight the bonfire seemed the most likely destination.
With nothing to lose, I decided to try something desperate. The store box was placed in the bath, the boards put back in and then the box filled with water. A heavy weight on the top of them kept them under the surface.
After a couple of hours they were transferred to the kitchen worktop. The first thing I spotted was that they were now perfectly flat again. Soaking wet, but flat.
To try and persuade them to stay this way, every available weight was placed on top and they were left for 36 hours to dry out again. This meant fish'n'chips rather than cookery for tea but sometimes you just have to suffer for your art...
Anyway, the boards are now up and look OK. I'll check and let you know how they have fared. In the meantime, would any wood fiends out there care to comment ? My feeling is that storage in a plastic box has dried the plywood out and that caused the twist. If I get them flat and varnish both sides, hopefully this will sort things.