just a quick question out of curiousity about glassing the inside of a box?

so what does glassing the inside of a box help out with??

Air leaks, rigidity, airflow.

Flex and airflow.

Oh ok thanks something I never really knew

If you are incorporating it for the sake of adding strength proper bracing can go a long way. Put a large dowel across the inside of the enclosure. Anohter very key reason I use fiberglass RESIN on everything is to improve the longevity of the wood. I have had many subwoofer enclosures that get a little bit of water on them and leak over time (or become moldy), so if it is an "exposed" surface that isnt covered with carpet or vinyl, it gets resin.

does NOTHING for strength...especially when just using resin and no cloth

It adds an estimated 2db, according to research.

2db huh lol well to be honest Idk if I was gonna add it or not I kno my guy that builds my stuff glasses the insides of his boxs every time so was just seeing if I should do it or not lol all I kno is I hope this box comes out at a proffesional level bhe made me the designs so hopefully i can just follow instructions and it turns out well just a simple box for 2 12's rear facing trunk build should not be too hard