When you're installing oversized speakers in a vehicle, one way to improve the look of the installation is to build a customised fibreglass pod to house them. Fibreglass is extremely flexible and will allow you to build a pod that matches the space in your vehicle -- not only in looks but in style. In addition to the range of shapes you can create, you can also build your pod with in a variety of colours, from flashy to subtle.
Measure the space in which you wish to install the pod. Be careful to include the dimensions of any irregular shapes, such as the indentation of wheel wells or the hump over the driveshaft. Also measure the inner circumference of the mounting flange on the speakers themselves.
Build a frame from MDF to the dimensions you measured. The frame should define and support the outside edges of the pod, and should include round frame holes with dimensions that match the inner mounting flange dimensions you measured. Cut the framing pieces on a table saw, and hold them together either with nails or with quick-setting construction glue. You do not have to cover any gaps in the frame with wood.
Place the frame in the position where you want to install the pod to test the fit. Also check the fit of the speakers in the frame holes. Make any needed adjustments before moving on to apply fleece.
Drape a single layer of fleece over the frame. Stretch it so it is taut and staple it into place. Staple the fabric in the underside and/or rear of the pod so that the stapes won't show. Cut smaller circles in the centre of the speaker holes and staple the fleece behind the hole frames.
Combine the resin components, following manufacturer's instructions. Use a digital scale to measure the proper amount of resin and hardener by weight. Blend the two components together thoroughly in a clean container, using a mixing stick.
Paint the resin onto the fleece using a brush, completely saturating it. Allow it to completely harden for the time specified by the manufacturer.
Apply pieces of fibreglass over the hardened fleece. Do this by mixing a new batch of resin and painting it onto the surface of fleece, then pressing fibreglass batting onto it. Apply a second coat of resin over the batting until it is saturated. Allow the resin to harden, then apply more layers of batting, using the same procedure, until the pod is the thickness you want.
Apply a layer of fibreglass-based body filler to produce a smooth final surface. Combine the two-part filler following manufacturer's instructions. Smooth the filler to the surface of the pod with a spatula or putty knife. After it hardens, sand the body filler smooth with a disc or flap-wheel sander.
If you want integral colour in your speaker pods, add a colourant to the final layer of body filler. You can also use a fibreglass-compatible primer and then spray paint the pod to the colour you desire. Another alternative if the pod is open-backed is to apply the fibreglass batting behind the hardened fleece rather than in front of it. This will give you a smoother surface and eliminate the need for body filler.
Epoxy resin emits harmful fumes as it cures. Always apply the resin in areas with good ventilation.