I have an Aluminium Folding Table. The Top has warped and Buckled. It is made of Hardboard(?). I have attempted to soak it with water at the back, turn over and put a very heavy concrete ornament on the Front. I left it for a week and the result was OK but it has now lifted again. I am thinking of replacing with maybe a sheet of Perspex or similar. It is the actual fitting I am seeking help for ( how to set it in). You will see from Photos that it's not possible from under the frame. There are however plastic corners. I think these Tables are probably put together under pressure? There are no screws used to hold original Top in. I am not fussed if I have to have a removable top, it's getting it in that's the issue.