How many layers is enough for 3 15s?

So as some of you guys might already know.. I am putting 3 15"s in a fiberglass enclosure in the back of a PT Cruiser.

I just finished my 3rd layer of chop mat on the outside of the enclosure. Now, my question is.. I don't know how many more layers to go!. When I press on the curved areas after the 3rd layer dried.. it didn't budge. When I push on some of the flat areas, they don't flex or budge either. Now, I realize I need to put more layers on. My next step is to put a layer of mat on the inside.

From reading past posts, some people say 3 layers is enough.. some people say 7 is enough. But, no one takes into consideration if it's chop mat, what size chop mat, or what about cloth!. As for my scenerio, I am using 1.5oz chop mat, and nothing else. So being I am using chop mat.. how many layers should I apply?. I figured 3 on the outside (which is done), and 3 on the inside. Is that too much, or too little?.

I usually try to use 4 layers of 1.5 oz. mat.  But 3 should be sufficient. 

BTW, you can lay down up to 3 layers at a time.  That should save you some time.  Just be sure to have the pieces ready to go before you mix your resin.

Steven Kephart

Adire Audio