I've decided to make my own sub enclosures for my truck and save myself $700 from the estimate. I've got a pretty damned solid wooden box made out of 1/2" MDF, screwed, glued and siliconed shut so that it's airtight. what I NEED to do is make a perfect contour out of fiberglass to attatch to the bottom of the box so that it can sit flat and even on the curves of the truck's floor. all the sites I've been to have just assumed that the box was going to be a permanent addition to the vehicle and have told me to use the hardener on the mat directly on the carpeted area... would applying 2 layers of aluminium foil to the area I want to mould be a good idea to keep the fiberglass from gluing to the carpeted bottom? I was thinking of lining the bottom with aluminium foil, making a hard fiberglass shell ON the aluminium foil, then when it was all set and dry, taking the shell off, sand it and attatch it to the bottom of the subbox. is this a good idea or no? I know that some adhesive compounds react "wierd" to aluminium foil, causing chemical reactions that produce chlorine gas, or even cause a replacement-oxidation reaction that creates enough heat to start a fire. would the hardener compound for fiberglass react this way? I'm hoping I'm not sounding like a complete n00b to 'glassing.