BUILD A FIBERGLASS SUBWOOFER ENCLOSURE

THE PARTS LIST

Although this section shows you how I built my speaker enclosure, it can really be applied to building anything out of fiberglass. Make sure whatever you try, even if it isn't RAVie related, you take tons of pics. I'd love to see what you're doing!

Plan it out! Draw out your ideas if you can. Think about what shape you want. Gotta have at least a basic idea of what you're building. This is the empty cargo space begging for bass. While you're planning, you can gather your materials. Good tip is to hit up your local casinos that have slot machines! Anywhere that has slot machines surely has coin cups, usually with the casino logo on them. This implies that they'll allow anyone to take a few home with them for advertising purposes. Those cups make for PERFECT resin mixing containers! Also hit up your local 99 Cent store. You can get the packs of 5 paintbrushes for under a buck. $5 worth should be good. You can purchase polyester resin at your local Home Depot or Lowes, or any car parts shop that sells bodywork supplies. You can pretty much get ANY polyester resin you like. I mostly used [EVERCOAT RESIN] because that's what Home Depot had, and the big 1 Gallon can was about $30. The fiberglass mat or sheet I also purchased from Home Depot pretty cheaply. Depending on which mat or sheet you get, they absorb the resin differently, so I'd recommend getting at least 1 package of the thin stuff, and the bulk of the fiberglass will use the thick stuff. Finally, Spray Adhesive. Get the cheap stuff, as it just needs to hold up some foil sheets.

Protect your interior! Here I lined the area with saran wrap. You can't over-line it so don't skimp out, and put a few layers on there making sure to overlap the spaces as to prevent any leaks from reaching your interior or floor.

Now line the area with aluminum foil, using the spray adhesive to stick the foil to the saran wrap. Again, put on multiple layers with spray adhesive. This will allow you to stiffen your work area to be able to work out any creases in the foil as much as possible. In the picture below, I taped up the places where the foil overlaps so that resin cannot leak underneath it.

Let the fiberglassing begin! Turn on your fan and make SURE you are breathing fresh air at ALL TIMES! Resin fumes make you high! Mix your resin with the instructions you have on the can of resin. It should have come with a tube of catalyst, and the instructions are usually as vague as "use one tube of catalyst per can of resin, and half tube of catalyst per half can of resin". A lot of this also depends on your climate. If it's a nice warm day, stick with the recommended ratios. If it's under 60 degrees Farenheit, I'd wait for a warmer day. If it's less than 70 degrees, put slightly more catalyst in your mix. You should get the hang of it after your first batch is applied and dried.

Below is after applying my first layer of the THIN mat. The advantage of using the thin mat first is that all you initially need is something to hold up the shape, and if you use the heavy/thick mat first, it will absorb too much resin to be able to hold itself up, and there's a good chance you'll have fiberglass oozing down from gravity. I prefer brushing on a coat of resin on everything first, then strategically cutting and fitting pieces of the thin sheet everywhere. It'll stick from that first layer. After it's all in place, brush on more resin until all of the visible mat is saturated. Make sure to work out any bubbles by dabbing with your paint brush.

Depending on the weather and your mixing ratios, it can take anywhere from 15 minutes, to NEVER to dry. If after a few hours it still isn't dry, try using the heat of a hair dryer. If that doesn't make it start to get tacky and start to dry, you may have to scrap everything and start it over. This really shouldn't happen unless you barely put any catalyst in your mixture. Now put on your second coat of resin and mat. Put as much on as you can without having it sag anywhere. You should be smarter with how much catalyst to mix. When it starts to dry and the layers get thicker, it will take on a pinkish or greyish/tannish coloration. Give it a tap to see if it's stiff enough to retain it's shape when removed. Make sure to layer thick on the edges as well.

Looks thick enough now! Let the stripping begin! In the picture below, I'm in the process of peeling out the glob of dried fiberglass. If you did step 2 correctly, there should be absolutely NO resin anywhere after you remove the figerglass from the vehicle!

Great start to the back side. Stiff piece not 100% dry, but that's okay. Now there's a pretty messy job with peeling away the foil and saran wrap. Since it isn't completely dry, most of the foil will peel off. There'll be spots where the foil is embedded into your fiberglass, but that's okay.

Below is after I peeled off the foil, and after I trimmed the edges with tin snips. At this point the fiberglass piece isn't as thick as it will be. I don't want to thicken it just yet, because since the shape is irregular, much of the resin will drip off. So for now I'm done with the back side.

Below I'm checking for fit. Of course it's a perfect fit, which means I'm not wasting any unused space by putting in a cubical speaker box.

Build the front of the enclosure! Typically fiberglassing work involves a mold, which if you think about it is precisely what we did so far with the foil-lined interior. But what about the front of the enclosure? Since I didn't have a mold, I designed the enclosure from the inside out. I cut cardboard pieces to mimic the basic shape that I wanted. Make it as big as you can without exceeding any of the dimensions you desire. Now mount your woofer in the cardboard box and you're done! Don't the pictures below look nasty?

Get your handy dandy canned foam. This stuff is dirt cheap at like $2 a can. I used like 3 or 4 cans total. Start spraying the foam all over the cardboard to build up the shape of the speaker box.

It's easy to go overboard with this foam. Keep in mind that it expands when it dries! The below picture likes like a big pile of yellow crap! Hopefully you can see it starting to take a shape.

I think I'm all foamed out at this point. I made sure I have foam larger than the shape of the enclosure I want. Now's the time to put on your artist's hat!

SHAPE UP, or SHIP OUT! Time to trim the pounds. I first used a long blade Xacto knife to trim away the clumps of foam. If you are in a dry climate when doing this, you WILL look like a snowman after doing this step. Don't ask me how I know! Already starting to look sexy in the picture below.

Starting to look familiar? During this phase, you may have to trim edges of fiberglass, and fill gaps with foam, and do more slicing and rasping. Frostyyyy.. the snoooowww mannnn. Keep doing this until you get the general shape that you want. I think the picture below is where I started showing some teeth.

Build the front! Wrap your whole foam mess with saran wrap, again overlapping redundantly to make sure that there's no way any resin could leak thru. Below is the wrapped snowman installed in it's home. Looks like a good fit. Any imperfections or dips will be filled in later.

Layer on the fiberglass like you did before! I left the front portion thin because I wanted to shape it with a face plate. Below shows the result.

Here's the front piece and the back piece. I trimmed the edges with a dremmel so that the pieces would fit snugly with each other. You see where I'm going with this, right?

Build a faceplate! I cut out a faceplate from 1/2" plywood, and I trimmed the shape out of the front fiberglass piece so that the wood fit snugly in the fiberglass, as in the picture below.

Wrap the backside of the wood trim piece with saran wrap so that no resin can leak thru and reach the wood. Now with the wrapped wood inserted in the front panel, lay the front panel on it's face, exposing the back of the wrapped wood piece and the "inside" of the front panel. Fiberglass away, let dry, and trim. See the pattern yet? Below is the result.

Now that you have a "lip", you can turn the front panel face down, and thicken all of the walls with fiberglass mat and resin. The thickness depends on how "strong" you want your box. More powerful subwoofers would require VERY solid boxes, but if you're using a whimpy sub then you can make it relatively thin.

Mend the front and the back. Trim or grind edges so that both pieces fit together well. Then shove strips of mat in the inside edges and soak with resin. Once that's dry. You can fiberglass the heck out of the inside of the box to make it as thick and strong as you want, without having to worry about leaks! Any gap on the outside you fill with fiberglass mat and resin as well.

Sand sand sand! I used hook-and-loop disks on my drill sanding attachment. Makes for VERY quick sanding of large areas. Make sure you have adequate ventillation, and wear long an old long sleeve shirt with rubber gloves... and of course wear eye protection. Any piece of skin that touches the dust from sanding will become very itchy. Sand it as smooth as you can, and if there are any thin spots, then by all means thicken it from the inside! Use bondo with a wide putty knife on the outside of the box to fill in any low areas.

I sprayed a light coat of sandable paint on the outside of my box so that when I sanded it with a large pad, the low spots would be visible. After I was happy that everything was smooth, I test fit the enclosure, shown in the picture below. Looks like a PERFECT fit.

Finish your box with whatever you want! I chose carpet because I found a pretty good match at a auto fabric supply shop, and I stretched vinyl for the front plate. Then I bolted down the front plate from the inside lip of the enclosure by reaching thru the speaker mounting hole, and mount your terminal plate, port, subwoofer, and wiring. Dude... you ROCK!

Please feel free to if you have any questions. Happy RAV'n!