What kind of bracing for interior of sub

can any one tell me what kind of "bracing" do I need to put inside of a sub box and also exactly what kind of "glue"?? I have a sealed box with 2 12" rockford hx2

Also, should I fill the inside of box with fiberglass insulation...Thanks

What thickness MDF did you use ? If you used 3/4" - 1 " MDF you probably will not need bracing because it's a sealed box. We use normal wood glue and air nailer to build the box , then we bead the inside of the corners with a rubber compoundto seal it off. For competition boxes we fiberglass resin the entire interior of the box to make it air tight. Filling the box is only necessary if you built the box smaller the the specs require. If you did not, then you will not have to fill the box.

another trick you can do is to get some of that bed liner spray.  This not only seals the box but also adds sound deadening and vibration control which helps stop fatege with the MDF, nails or screws, and glue.  That's the only problem with using fiberglass resin, It fails over time.  At least if the box is used hard. 

If your design warrants using internal bracing make sure that you router all the edges off so that the air moving inside the box moves smoothly around the brace.  I would stick to using MDF strips cut about 2" wide for the braces and make sure that the braces do not touch the wofer at all.

Most of all.   Take you time and do it right the first time.  Don't let your buddies rush you into building a junker box.

Using these methods you will build a box that really rocks(as long as your air volume is correct). 

thanks jeff at velocity motors and also Dean at Chase asseccori for the info on sub box bracing