Try wax on wax off for a minute grasshopper. Have you used any of the medite which l put the link up. Or even read the spec. Not saying use it in yours or anyone else's boat. I've used it so can voucher for it being more than adequate for outside use open to all elements. For you to just blanket the use of all so called waterproof MDF as no good is what I was responding to. So just wind your neck in from between your arse cheeks for a minute if can. I think it was another old bod to use your words which pointed you to a new product you new nothing about regarding wall panels.