Fiberglass Speaker Box

       One of my strong interests is Car Audio. I bought my first powerful stereo a few years ago and proceeded to build a box for the subwoofers. Which turned out to be a little too large.

Instead of building another MDF box, I decided to remove the spare tire and make a box custom molded into the spare tire well.

To start, I first laid down a layer of aluminum foil and masking tape. This would keep the fiberglass from bonding to the car and making it very difficult to work on or remove later.

Once that was completed, I laid down several layers of fiberglass mat and resin.  Once I had about 3 layers down, it was strong enough to be removed from the car. I then added 2-3 more layers to make it stronger.

With the bottom half completed, I then had to cut the rings that will be used to support the subwoofers.

using a router with a home-brew circle jig, I was able to cut some pretty nice circles.

and also make a pretty big mess.

 The finished rings. Using the 2 rings gave a nice flush mounting surface for the woofers.

With the rings ready to go, I was able to play around with the location and angle of the subs. Using some ½” dowel rod, I was able to secure them in the final position.

 With the rings attached, I then covered the enclosure with some fleece material. The fleece was used because it was stretchable in all directions, which gave a nice smooth finish.

The fleece was then covered in several coats of resin.

After letting it sit overnight, I put the subs in and put some power to them.  It rattled and flexed quit a bit. Upon closer inspection, I noticed that the bottom layers of fiberglass mat weren’t layered properly, leaving some air bubbles between each layer. This is probably related to my lack of experience with fiberglass. To solve this, I just ‘injected’ some liquid nails into the air pockets and sealed the hole with a piece of duct tape.

To finish it up, I bought a piece of automotive carpet and some spray-on glue.

The finished product.