Originally Posted by pg6speed

I use hot glue to attach the wooden frame to the fiberglass mold and also to glue the fabric to the mold and wooden frame. Spread resin over the fabric and let dry. At this point start adding layers of glass and resin. I do about two to three layers being sure to get any air bubbles out as I go then let dry. Last I add two more layers. The thickness depends on how big the area is and how many curves there are. The longer and flatter the area, the more layers I use. The more curves there are you may be able to get away with less since the curve will add strength. I wouldn't use less than 3-4 layers in any case.
If it is built thick and strong enough with no flex it will sound just as good as any mdf box.