fiberglass sub box
typically when dealing in subwoofer boxes you want to use 3/4" MDF it helps with the sound properties of the woofer, be sure that you use wood glue and seal all the seams. also you want to make VERY sure that you build the box to support the woofer your using as every one calls for a different volume of space. not sure the way you guys are making it will have good or bad results as ive not built boxes like that before. only tips i can give is 1) dont be skimpy with the resin and 2) double check that your box has the right amount of air space for your sub. you can find that info on the manufacturers wed site. as for they type of glass the stuff you saw at home depot is what we primarily used at the stereo shop i worked for. cut it into strips about 2 by 4-6 inches long. that will help with strength. over lap them and crisscross them.