How to Make Fiberglass Molds for Subwoofers
- 1). Clean out the area of the vehicle where the box will be located. Leave the carpet and make sure it is as smooth and perfect to the contours of your car as possible. Suck up any debris and dirt with a vacuum.
- 2). Create a layer of tape in the area that you will be fiber-glassing. Two crisscrossed layers will ensure you don't get resin seeping through to the carpet. Be sure to tape off two to three inches past where your box will go so the fiberglass can be trimmed to the exact shape you want.
- 3). Tear the fiberglass matte into manageable strips about 1-by-4 inches. Be sure that you are wearing a mask and gloves at all times when handling fiberglass and resin as the fumes can severely harm you.
- 4). Mix the recommended amount of hardener and resin that's listed on the package into a small cup no more than two to four ounces at a time. Small mixtures make it easier to handle in the trunk and less messy.
- 5). Dip your brush into the resin and spread it over the taped off area. Place strips of fiberglass on the resin. Use your brush again to dab resin onto the strip until it turns mostly transparent. Continue laying down strips and dabbing resin until the taped off area is covered. Let the fiberglass dry for around two hours and then add an additional few layers so the box is strong.
- 6). Draw a line where the edge of the box will be, then remove the fiberglass and tape from the car. Use a Dremel, jig saw or other cutting device to work your way along the line, trimming off the excess fiberglass.
- 7). Construct speaker rings by cutting circles out of 3/4-inch MDF. Your sub-woofers should come with a template to help you with sizing.
- 8). Place the speaker ring in the box where the sub-woofer will go. Cut at least 4 dowel rods to the length between the box and the speaker ring. Position the speaker ring and dowel rods and use hot glue to attach it all to the box.
- 9). Stretch the fleece over the large opening between the fiberglass and your speaker ring. Use hot glue to attach the fleece to the top of the fiberglass area. Stretch the fabric over the MDF to the other side of the fiberglass and secure with hot glue. The fabric should cover everything that is not fiberglass and be wrinkle free.
- 10
Paint the fleece with resin using the same mixture as earlier. Saturate the fleece with resin until it's soaked through completely. Add four to five more layers of fiberglass to the fleeced area following the steps used earlier. - 11
Cut open the sub-woofer hole and trim the fleece using a Dremel tool or similar. Trim the fleece as close to the MDF speaker rings as possible for a cleaner look. - 12
Drill a hole in the back of the box for the speaker wire. Make sure once the wire is run through to seal the hole using silicon to make the box airtight again. - 13
Lightly sand bumpy or bubbly areas of the fiberglass until the box is smooth. Attach the carpet to the box once you have cut it to size. Use 3M adhesive spray to adhere the carpet to the box. - 14
Place the box in your car to make sure it fits. The easiest way to prevent the box from sliding around is using a few small strips of Velcro to secure it to the floor.
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