[dazee]

Thank you, this is very useful and at this stage I will just try to repair in the corners with a contact adhesive first.  I did lay the braid fairly loosely, trying not to tighten it.  But with the lifting being just on the corners, I was suspecting some tightness.  I have not dared to run cars with magnets on this yet - is nagnabraid.  I think it would just lift some more, so trying to fix first.  If I have to rebraid or even remake the track then so be it.  If just a single sheet of MDF and some time/effort wasted.

A major difference may be that 3M tape used.  The one I have used is F9469PC which I had taken from another posting on laying braid.  I will order the one you mentioned and give that a try on some test sheets too.  One other poibnt O have seen, someone using a hot air gun on the tape before applying the braid to it.  Recommended or not?