This article is from the Car Audio FAQ, by Ian D. Bjorhovde (email@example.com) with numerous contributions by others.
Building custom kickpanels for your car is a fairly advanced task, and
requires knowledge (and experience) in working with fiberglass. Auto
Sound & Security published an article in the August 1996 issue that
covered the basics of working with fiberglass.
This is kick panels in a nutshell. It takes about 2 days to do this
right, although it is possible to do overnight (a LONG night) in one
Step 1: Cover base area with plastic & duct tape.
Step 2: Lay fiberglass over the entire area. Don't worry about getting
the pieces cut to the exact size and shape, you will trim them later.
Step 3: Build the baffles for your speakers.
Step 4: After the fiberglass has cured, set the baffles (with the
speakers properly mounted into the panels and use a backstrap to secure
the baffle to the panels. Now, spend some time listening to the car and
aim the baffles until you get the best image and stage in the car.
Note: Take your time aiming the speakers - once you fix the baffles,
you won't be able to readjust the speakers. You may want to spend a few
days listening to different positions to determine what sounds best.
Step 5: Remove the speakers from the baffle and fill from behind with
self-expanding insulation foam. This will allow you to mold the baffle
into the rest of the car.
Step 6: After the foam has hardened, sand it to the shape you want the
panel to have.
Step 7: Lay fiberglass over the foam to form the top panel of the kick
Step 8: After the fiberglass has hardened, sand the surface smooth.
This may require the use of a little bondo to get things perfect.
Step 9: Remove the foam by grinding it out from the inside of the
Step 10: Cover the panels with carpet, vinyl, leather, fleckstone or
other substance of your choice.
Step 11: Install the kick panels in the car.
Step 12: Install the speakers in the panels.
Step 13: Make speaker baffles from Plexiglas, and grilles.
Step 14: Enjoy.