I have a double cut Gibson that I am converting to lefty. In moving everything to the other side I duplicated the control cavity in reverse. I now need to cover up the original control cavity and volume/tone holes. What is a god material to use. I keep hearing "marine tex" and NOT to use bondo. I have used bondo in the past to repair damage to mdf panels used for arcade cabinets. I'm pretty good with it and feel pretty comfortable with it. I know I can shape it as needed. I tried to use some so-so quality wood fill in combination with some dowels to plug the pot holes. It didn't work out so well and I have remove it. It shrunk a little but never got as hard as I know bondo can get. Wood fill is not meant to be used to fill large holes.