Fiberglass help!! Porting??

[bumpn_gt]

I have given up on the wood project. I was never able to get the front of
the box screwed down (sat too high to get my arm in there to screw) so I
decided to go with fiberglass. This way I can make the most of my space and
still have it look really nice. My question to you.......how the hell do you
port a fiberglass box? How do you figure out volume? I will be using 3/4's
of my trunk, any space I can consume and still get the box out is my goal. I
know the DD 9515's like big *** boxes, so I want to have them at their best. This is going in the trunk of a '93 caddy sedan deville with a Planet Audio 2500d strapped on to each sub.
Let me know your thoughts!
Thanks

[Zacmc212]

From what i have read, u can use packing peanuts or water to find out the internet volume, then use 3-4" pvc for the port. What i was going to do was make the box and aim for most airspace possible because you can always add foam inside the box to size it down. And then once it was done add the port and mess with the port lengths to get the tuning right.

[bigred78797]

Or if you want to do a rectangular port u can use balsa wood to form the port.

I usually make the balsa wood 1/4" larger on all sides of the port.
Then i begin to Fiberglass the exterior of the balsa wood to about a 1/2" thick or more depending on the application then finally lay down about a 1/4" of fiberglass on the inside of the port.

U can usually lay the inside of the port and the front face at the same time for time saveage then use the speaker holes to fiberglass and reinforce the interior. Thats just what i do. There may be eisier ways. There should also be a tutorial around here somewhere if u do a search.

[snebes]

This is something similar to what I was planning on doing. Considering that you won't be able to take the box out and put it on its side, you can't find the area with peanuts or water. I was just going to try and mathematically get close, and use 4" PVC for the port. Make it longer than needed at first, then cut it down till i like it.