Fiberglass Basics

Well thanks to all your guys help on my past posts.. I know what i'm doing now thanks to you guys.. and before I do it, I just want to tell you guys what im gonna do and please let me know if im wrong..

First off.. I have 3 15"s. I'm going to get 3/4 MDF, make a sealed enclosure, and not chamber it.. but brace the hell out of everything, especially the rings. I plan on permanently bracing the rings as well just for piece of mind.

Now, as for the fiberglassing part.. I think i'm right about this.. but please, if I am.. or if there is a better suggestion.. please let me know. Here are the steps I plan on taking unless i'm told other wise...

- Wrap cotton (tshirt material).. and resin it.. let it dry, but not completely.

- Wrap again with fleece.. resin it.. let it dry completely!

- After resin is fully dry.. time to fiberglass. Fiberglass from the inside. About 6 or 7 layers of fiberglass to make sure it can handle the weight of 3 very heavy 15"s

- Glop Bondo and spread on the entire outter box.. sand.. bondo.. sand bondo.. however many times it takes to get smooth.

- Spray on a few light coats of primer.. paint.. then some layers of clear coat

Thats the steps I plan on taking. My main questions are. I heard its MUCH easier to fiberglass on the inside.. is that true?. Also, is 7 layers too much or too little for 3 subs?.. and finally.. what kind of fiberglass do I use for the 7 layers?. I saw there is chop mat.. and some that are different ounces. Which do I use??.

Like I said.. any help is appreciated.

Thanks!!

First I have the bottom of the box molded to the car with plenty of layers for strength.  After I stretch and resin, I fiberglass the outside of the box (over the fleece).  I've heard about laying inside, but have never tried.  7 layers should work fine.  Test it out before finishing the outside to make sure you're happy with it.  Then you can add more if desired before you bondo, etc.  I use one-and-a-half ounce mat.  I ordered a 6" wide roll for around $26 from www.shopmaninc.com.

7 should be plenty, but if you have trouble fiberglassing on the inside, and are a little worried about strength, just add a few layers on the outside, or if you are worried about not getting it smooth enough, then add some kitty hair bondo on the outside.