Cut out the MDF base for the enclosure. Cut the MDF large enough to fit your subwoofers. Determine how you want the speakers aimed. This will show you how wide the base of the enclosure should be. See the resource section for diagrams.
Cut and glue the dowels to hold the speaker rings in the correct position.
Wrap and glue the fleece or cotton fabric. Stretch the fabric as tightly as you can.
Apply the first layer of resin. After some time the enclosure becomes rigid.
Start building the mat layers. Apply resin to the mat layers with a paintbrush and smooth out any air pockets. Apply the mat layers and resin until the enclosure is completely sturdy. Gage the sturdiness by applying your full body weight.
Sand the subwoofer enclosure completely with 80 grit sandpaper.
Apply an auto-body filler using thin coats.
Continue to apply the auto-body filler then sand between applications until all holes and dimples are filled.
Remove any dowels that have become loose.
Paint the enclosure with glaze to cover any pin holes or small dimples.