The ply is 3.6mm thick as sold by B&Q a U.K d.i.y. store. It really is cheap nasty stuff with faults in the veneer facing and even occasional voids within the ply.Guess where it comes from ? - not Scandanavia. You have to be very selective when buying a sheet. I had always intended to paint this one anyway.
howdy tim,i stopped by to answer your questions about the resonator coverplate.i leave it flat after cutting it but i use hole punches to make the inner holes around the center hole and when i punch them it leaves an uneven surface so to make it all smooth again i use a brass hammer to hammer it out from the underside( cause i punch the holes from the top side)when i hammer it out smooth it makes a slight arch to the coverplate any uneven ridges there may be in inner surface areas of the holes i usually use a fine line half round file to remove then sand edge with average grit sandpaper.oh also when i am hammering the coverplate from the underside i set it on wood surface instead of metal and that helps to preserve the patina of the surface of the coverplate.also you asked about regular baking pan---the ones i look for are well used and have the patina prebaked on the surface from many cakes being baked in them.sometimes i like the look of the outside of the pan better when its patina looks nicer and more evenly distributed.thanks for your interest and your questions.have fun and hoped what i had to say helps you out.