Part 2: "After the Fiberglass...."
Here's the finished fiberglass "shell", with the outline of the front panel traced onto the MDF.
I used "t-nuts" to affix the front board, because the 3/4" MDF does not hold screws very well, and also to make the panel easily removable.
The visible parts of the enclosure need to be smoothed- not an easy task with the fiberglass underneath. But Bondo body filler worked well. Here we see a large "canyon" that needed to be filled in. Rather than use up a whole can of bondo, I first glued in a bunch of cut-up MDF blocks, then smeared Bondo in the gaps- an "amalgam", just like dentists and stone masons use! Once the Bondo cured, the whole clump was easily sanded smooth. MDF sands easily (but dustily!), and so does Bondo, especially after it has "set up" but not yet fully cured.
Here is the same area after smoothing the amalgam and another coat of Bondo. That "fin" along the top will close up the gap between the top of the enclosure and the top edge of the trunk. And the bottom of that filled-in area in the center of the pic is now a handy place to grip the enclosure (and a good thing, too- it already weighs 15 pounds without the woofer!).
Now we go back out to the trunk for a test-fitting. Notice how the "fin" closes up the gap above the top of the enclosure. I could not make the enclosure itself taller, since the thick trunk lid occupies that area when it is closed.
The woofer should arrive any day, so it is time to get the enclosure wiring ready. I drilled two 3/16" holes into the rear of the enclosure 3/4" apart and installed female banana jacks. Then I sealed up the ends of the open banana jacks with dowels (chopsticks again!) and schmeared Elmo's Goo-all to make an air-tight seal. Here is a view from inside the enclosure:
The outside part. Notice the black heat-shrink tubing to identify the negative connection:
A dual banana plug now fits perfectly, and when the enclosure is removed from its usual location, no wires will dangle from it:
Here's a ventilation panel I salvaged from a Rolm PBX power supply several years ago. It's one solid piece of 1/16" steel, yet it lets through all the air- perfect for protecting the speaker in a trunk, and also a good material to glue carpet or vinyl to. I always knew it would make a great car speaker grille someday, so I'm glad I kept it.
The front baffle board after cutting the 11" hole. I wanted to use a router but couldn't find anyone that had one. A jigsaw worked fine. Notice the eight holes around the perimeter- I recessed each one of them so that the t-nuts won't protrude, keeping the front board totally flat.
To strengthen the front board, I glued 4 pieces of MDF around the perimeter. This forms a nice "pocket" to secure the woofer, which I am mounting to the inside surface.
Lots going on in this pic. The wires have been connected (I mounted the woofer with the "Infinity" logo upside down- that placed the gold wire mounting posts closer to the top, keeping the wire run as short as possible). You can see the brown high-density weatherstrip placed around the perimeter of the enclosure to provide an airtight seal. I used some to seal the woofer against the inside of the baffle board, too.
Well, it took 14 drywall screws and 23 8-32 machine screws (and 23 t-nuts), but here it is all assembled- good thing I had a power screwdriver! The grille is about an inch too short to cover the vertical height of the speaker hole, so I couldn't secure the center holes of the grille. To keep it from rattling once the woofer gets cranking, I used a lot of that same brown weatherstipping foam between the grille and baffle board. That grille is 1/16" thick, so one day when I get my hands on a router I will cut a recess and make the front board perfectly flush. The front board is easily removable at any time for such re-working. I took the enclosure inside the house and wired it up to my home stereo- as expected, with all those fasteners holding it together, it is one solid, 33 pound box. The only thing that rattled was the rest of the house!
OK- now we pop it back into the trunk. Notice how the top panel clears the trunk support arm by just a millimeter or two- a perfect fit! Once it is covered by carpet, it should just DISAPPEAR into the trunk (until the volume is cranked, that is!). And, yes, I know I need to water my lawn more, thank you.
An extra amplifier will be needed to drive this woofer, so some thick 4 gauge power cable must be run from the battery to the trunk. Here is how I ran the red wire through the rear seat area. FYI- It takes 12 ft, 3 inches of cable to stretch from the battery/fuse area to the opening leading to the trunk area you see there. So just add whatever extra you need to reach your amp location, and that is how long a continuous run of B+ cable you'll need to buy for the Lexus SC400 or SC300.
Remember the first pic from Page 1 showed the side trunk cavity. Well here it is again with a layer of RAAMmat on it. RAAMmat is a sound-deadener and rattle-reducer, similar to other products out there, but MUCH more affordable and very easy to work with- the results you see here took less than an hour, and this was my first time ever working with it! It's always for sale on eBay- just search on "RAAMmat".
On most cars, it is easy to pop off the rear seats and firm up the large metal panels in that area with some RAAMmat:
One final touch would be to cover the enclosure with automotive carpet to make it blend in with the trunk and become totally "stealth", but I love to show off the enclosure as is, so I have not yet done that. In fact, if you have a Lexus SC300 or SC400, you might be interested in buying this unique enclosure- for the right price, it is for sale (but since you've just seen all the work I put into it, don't expect a steal, ok?). The next page shows how I installed my satellite radio, and below are some final fiberglassing tips. Thanks for looking and if you want to know anything more about my project just email me at my AOL address: SOCALPERY
- PERRY
===========================
Final Section: List of Materials used and FIBERGLASSING TIPS
1 4' x'4' panel of MDF from lumber yard/home depot
1 can of spray adhesive
Corrogated cardboard, tin foil and mailing tape
1 package (1 sq yard) of fiberglass mat
1 gallon of fiberglass resin
4 small disposable foam paint rollers
disposable gloves
3 packages (3 sq yards) of fiberglass cloth
1 can bondo for milkshake (optional)
1 can of spray trunk liner (optional)
Dual-prong banana plug
Sandpaper and rotary rasp
Drywall screws, t-nuts and 8/32 bolts
Hot glue gun and Elmers Carpenter's Glue
Grille material
Trunk fabric for covering the finished enclosure
The wisdom you acquire by going through the process of fiberglassing is immeasurable- here are a few things I learned that I wish I knew before I got started working with fiberglass:
With so many vertical and inverted surfaces, you’ll want to minimize the amount of time you spend fiberglassing inside the trunk, therefore I should have used fiberglass mat as my first layer instead of cloth. It is possible that one layer of mat would have created an enclosure stiff enough for me to remove. That second fiberglass cloth layer did not go on very smoothly- several of the panels started drooping off the vertical and inverted surfaces (the resin disolved the spray adhesive!). I tried to fix it as best I could but I didn’t get a very smooth surface-if that happens to you, yank off the uneven layers before they cure and apply them elsewhere. But don't let it dry in place- that just creates problems. I managed to fix it by adding many more layers, but it will slow you down.
That slogan “measure twice and cut once” is WRONG- it should be “measure three times and cut once”!
It wasn’t worth it to ensure that the fiberglass conform to every nook and cranny of the trunk cavity to extract every possible square inch of enclosure volume- that makes the enclosure way too tight and more difficult to insert and remove. It’s important to visualize how the enclosure will be inserted and removed from your trunk and shape your enclosure accordingly to make that possible. I should have spent more time lining the interior of the trunk cavity with materials such as florists foam or modeling clay to smooth out the curves as much as possible.
To minimize the amount of tin foil liner that sticks to your enclosure, be sure to use the thickest tin foil you can find and smooth out the curves of the interior (see above) so you don’t have to “crinkle” the tin foil. The fiberglass embeds itself into the crinkles and is difficult to remove.
Again- none of these "mistakes" killed my project- it just slowed me down a bit. I recovered, as you can see above.
If you have read this far you are one hard-core car audio fan- thanks for reading and should you be pursuing a similar endeavor, good luck to you! Let me know how it turns out!
That's the end of the woofer section.
Check out page 3 if you'd like to see how I fabricated a custom bracket to mount my AudioVox PnP2 Sirius satellite radio unit to the dashboard of my S400.
