How to make Flanges
So you want to cut a piece of fiberglass and make it a removable feature in the future......say put a access door in the cowling. Piece of cake.
Obviously mark with a sharpie pen where you want the door and cut it out. Make the cuts as pretty as you can since you will be reusing all the parts. We use the Fien saw most of the time. After you cut it out use tongue depressors with hot glue (remember hot glue is not warm) and glue the door back in place.
Read the complete article on How To Make Flanges