what do i do after the 6 coats of fb

I try to level out the high areas of glass with 50 grit personally.  If you done laying down the glass do that and then bondo, sand and bondo/sand again and again as needed.

Where is the fleece showing?  If it's around the back I'd make a batch of resin and lay it on.

I'm using industrial strength velcro to secure a 150 lb enclosure in a 13 second suv.  WalMart... crafts section...

Not to step on anyone's toes...jfunk06, buyt120 grit, even with an angle grinder is a pain... use a coarser grit.  If you don't have a tank just get a "plug in" square sander or whatever you call them and that'll do the trick.  If you have big air bubbles, I'd sand everything down a bit and "spot" layer where the bubbles were and then resand.

Thats what i am saying.  I don't sand my actual glasswork, just the stuff thats really out of shape(a corner of the mette flipped up, ect.)  And when it comes to a flapping disc, i prefer to use 120grit cause its going around 7-8,000rpm and with that speed, 120 grit will burn through something real quik.  60grit will just cut through it like a knife!   And its always better to smooth with bondo than FG, for one reason, price.  Dont shave off FG just to add more, keep the FG integrity strong, and use bondo to cover imperfections.  Cause 10dollar diffrence in price is alot when you are doing a sub enclosure!

thanks for all the help. i appreciate all this help i will try to velcro it to the car hopefully it will hold. i dont have many bubbles on the outside but i do have some on the base the piece that sits on the car.

once again thank you

ummm... about the velcro... how heavy is your project? anything around 8 pounds or over should not be held with velcro. at about 35 mph if you get hit in a crash, there is almost no velcro that will hold. at 8 lbs, 35 mph the box will carry more force then most bowling balls being thrown at you. "Use the bolts, Luke" (sorry bad joke)

As for bubbles, they weaken the glass because it gives the glass an area to flex. If you are planning on using a hard hitting woofer, I highly recommend filling the holes and reinforcing them with another layer of mat.

Oh and don't use power tools to sand things down. it will just tear through it and it is a lot easier to remove a little than to remove too much and have to patch and reinforce everything.

Hope this helps. Ganbatte ne (good luck -or- do your best)