Simon---how damp is damp with the wood you are using? My thoughts were to use one hex tab and put some kindling around it, thus making a sustainable small fire that I can continue to feed. Once this is done I can place a larger wet log above this small fire with supports on the side. Sort of like roasting a pig. With this method I think you would be able to dry out a large wet log...given that you keep feeding the hexamine fire.