diyautomods.com

If your like me and don’t want your trunk cluttered up with obtrusive subwoofer boxes, or you just want some thing custom instead of the good old square stand-by, then a form-fit subwoofer enclosure is for you. I’ve made a few so I’ll show pictures from two different enclosures I did.
Supplies
Painters Masking tape
Fiberglass Resin and Hardener
Fiberglass Chop mat
Disposable brushes
Rubber gloves
Spray glue
Fleece

The first step with building a form-fit enclosure is finding the form you want to fit ;). Once you decide on a location you need to lay down some masking tape to protect you car. Lay strips of tape overlapping the last with every new piece. You should wind up with 2 layers of tape when your done, but you can never put to much if your not sure it’s covered. Just make sure the tape is as flat as possible with not a lot of wrinkles and extend the tape further than you plan to fiberglass. I also recommend laying some garbage bags over the rest of your trunk to keep the fiberglass from getting on everything. Sometimes it helps to draw out the shape of the box with marker on the tape before you begin fiberglassing. Its a neat trick because the fiberglass absorbs the marker and you have a nice line to cut later.

Once your satisfied with your taping job, I like to use a wax or a cooking spray as a mold release. Either spray or wipe it on generously over the whole taped area. Then your ready to start fiberglassing. Start by breaking the chop mat into manageable pieces, something that will conform to the shape you glassing over. Now it’s time to get messy. Start brushing the Resin hardener mix over the tape and sticking the chop mat to it. Make sure to cover the whole area you’re working with and keep it as flat and bubble free as possible. Over lap the pieces so there are no gaps. once the whole area is covered let the resin dry. If you have a heat gun it helps speed things up, but the sun will work well too it might just take longer.

When the Resin is almost dry or hard you can put another layer on. I like to put 2-3 layers (depending on the size) before I pull it from the car. Make sure it’s hard enough that it won’t bend or flex easily and keeps it shape before you do. If it’s not ready, don’t be afraid to put another layer on it. When you finally pull it the tape will probably come with it and your car should be fiberglass free. Peel the tape and you have your form and you’re half way there.


With the form release you can find the weak spots easily by pushing on it with you thumb and seeing if it flexes. You also want to look for any holes you might of missed, and make sure you edges are good and firm. Go over any weeks spots or holes with another layer BUT ONLY ON THE INSIDE, if you put it on the outside the form will be too big to fit back where it belongs. When everything is good and hard you can cut the shape of the box out and test fit it in the car. Now we need to position the speaker. To do this you need to cut s speaker ring out of thick sturdy plywood/MDF. I find it hard to cut a perfect circle so I buy mine on line from this guy ( [URL=”http://www.able-audio.com/”]http://www.able-audio.com/ [/URL] ) plus since the speaker ring is gonna be the basis for your shape you want it to be pretty damn perfect. Figure out how you want your speaker to sit making sure the magnet will clear the back of the form. Using some wood strips or dowel rod secure the ring in the position you decided using glue and/or screws.


With the ring securely in place it’s time to bring out the fleece. Cut a piece big enough to cover the face of your enclosure plus a little to wrap around the sides. Staple the fleece to the speaker ring and stretch it tight to the outside using spray glue to secure it to the sides. Now you have a good idea what you enclosure will look like.


More fun with resin and fiberglass. Saturate all the fleece with resin and let it soak in good, if it looks dry ad more resin it will only make it harder. I find that the resin tends to loosen the spray glue so I usually leave those parts till after the face is hard, if it releases the spray glue you will get wrinkles and the enclosure will look like crap :P.

Depending on the size and shape of your enclosure this may be hard enough, but if the enclosure is flexing when you push with your thumb you will need to add more strength to it using chop mat and resin. Try to keep it as smooth as possible to save you some time sanding later. If you are just carpeting the enclosure then not much sanding is necessary, just get the big lumps and globs out. I use a disc sander because anything else would just take too long. If your thinking about painting then get ready for a lot of smoothing and shaping with body filler. Now your ready for another test fit


We decided to go the simple route and carpet it for a more factory look.