Custom Fiberglass subwoofer box install (with pics- 56k go away)

[Thug Nasty]

Tutorial: How to make a fiberglass subwoofer enclosure in the spare tire area for a single 12”. You will NOT lose the spare tire.

Car: 02 WRX (sedan)

I was finally annoyed enough with not having any trunk space, so decided to be creative. I know it’s been done before hundreds of times but it was new to me. I had never fiber glassed before. It’s not as bad as it sounds.

Disclaimer: If anything goes wrong it's not my fault. Blindly follow these instructions at your own risk.

Materials: A gal of resin should do. $35
Fiberglass 4-5 packs $30ish
Wood various sizes $20-30. I used ¼ and ½ inch mostly.
Carpet: $10
Misc: brushes, staples, acetone, duct tape, painters plastic. ~$20
Final: $~120 give or take $20.

First I took some pictures, made some measurements, drew out a plan, got all the materials I would need and then went at it.

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• I took out the spare and all the trunk contents. Vacuumed and cleaned it out a bit because it was a bit dirty before I started. (NOTE: I have no idea how McDonalds monopoly pieces got in there?)

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• I then measured out and made a box frame around the spare tire well where I would be fiber glassing. (Picture of constructed box on later) I just used two wood screws in each part connecting the wood together, but you can use whatever because it will be glassed later. (note: I did not make mine perfectly square. I regret that deeply now. It would have been much easier.)

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• Duct tape time. Everywhere where there would be fiberglass I duct taped. Is this really necessary? Maybe not, but if any got through I definitely don’t want it stuck to the spare and area surrounding it forever. I’d do it to be safe. (Note: I left the screw attached onto the spare the entire duct taping time till the last two strips to make sure the space was perfectly centered the whole time.)

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• I used the painter’s plastic stuff to cover the entire trunk. The fiberglass will be stuck onto this (forever).

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• I laid the glass out first and made sure it was flat against the inside of the spare area. I left a little room on each side of the boards to glass them on later.

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• Resin time. I put a pretty thick first coat. Make sure you do the inside of the spare area really well and make sure it stays in the shape you want. This is how it will dry. No going back now. Note: use gloves, I didn’t, big mistake.

(sorry for the blurriness, but you get the idea).

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• Fiber glass the bottom some more. Few layers should be fine. Blah blah blah. This is how is should look when it’s dry and cured.

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• Top time. I decided to use a thin board for the top. Here was my idea.

I would do it this way so I could still store stuff on top of this without worrying about the sub hitting it. I fiber glassed the whole bottom. I constructed this top before attaching it to the rest of the assembly. Note: this is where I messed up, because my original box wasn’t square.

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• I put rope across that nasty section on the top (to strengthen it). I sanded the border where it will later be connected.

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• Screwed my amp onto some boards.

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• Put a hole into the main wood on the box. This would be for my speaker thingies. To make this size hole I used a drill with a door handle cutter-outer. Then epoxied it in there.

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• Make sure it fits.

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• I used the original carpet that was in there to make a template for each section I would be doing. Then cut out pieces to fit perfect in there. It will look like this. They are help up by little supports the same height as the box. I made a cutout for my amp too.

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• I figured out where everything needed to be with the supports and all. Glued them onto the boards. Then carpeted the boards. Note: with the carpet it adds a little width to each board. Keep this in mind when cutting your templates and whatnot. I had to go back and trim a few of them so they would fit after being carpeted. To carpet, I just stapled the carpet on the back of each board. I went through a ton of staples. The carpet was $10 at home cheapo and I still have some leftover.