Car Audio - Custom Door Panels
It is fairly simple to build custom panels to cover up amplifiers,
processors, and other components like the pros do. All you need is to follow the step by
step methods presented here, some woodworking skills, and some basic tools such as a
circular saw, jigsaw, router, sander, drill, hot melt gun, a very sharp knife (carpet
knives work great), stapler, etc.
Most panels follow the same construction process, no matter what
materials you use: Making a template, building the frame (base), raising (if necessary),
filling, smoothing and covering the panel. For example if you are making a door
panel, you would first make a frame out of wood, then round off the edges by filling them
with Bondo and covering up the whole thing with vinyl.
Step 1: Making a template
One of the easiest (and cheapest) methods is to use
cardboard for the template. For example, you are making a one-piece panel for the trunk,
that will go around a subwoofer and a couple of amps. Cut a (straight) end of the
cardboard box and place it next to an amp. Keep cutting pieces of cardboard and gluing
them with hot melt over each other to make a big template consisting of glued pieces of
cardboard. This way, instead of figuring out the shape of one big piece, you will have to
figure out the contour of a small part of the whole panel at a time.
Once you come up with a template, make sure you have no
gaps. If you have to bend the template to get it in and out, you will have trouble with
the final panel, since the panel will most likely not bend. You might want to split the
design in two or more panels. Plan ahead of time what material you are going to use to
cover up the panel, and subtract the thickness of the material from the panel. For
example, if you are using vinyl, you might want to reduce the outline of the panel by
1/8", but if you use carpet, maybe 3/8" will work better.
Place the template over the material you are cutting.
Trace the outline with a pencil. Cut using a circular saw on the flat parts, and a
jigsaw on the curved parts. Use good saw blades to get smooth cuts (this will save you
some work later).
After the panel is cut, take it back to the car and
make sure that it fits, check that whatever material you are using to cover it up fits in
between the gaps. If you took the time making a good template, then the panel should be a
pretty good fit.
Step 2: Raising the panel
If you are making a flat panel, then go to step three, if not, keep
reading. On this panel we are making as an example, we are planning to raise edges around
the panel to outline the amps. Make a square "ring" around a hole and screw it
to the main panel. Then, make another ring (this one smaller outside), and screw it on top
of the first ring. Keep going until you get to the desired height and shape. (It is a lot
easier to do various 1/4" levels, rather than trying to shape one thick piece of
wood. You only have to get an approximate shape. The gaps will be filled on the next step.
Fiberglass can also be used here.
Step 3: Filling and smoothing out edges
On the previous panel, there are gaps in edges of the layers of
rings. Fill the gaps using a material such as Bondo. Try to get a shape as close as
possible to what you want. Once the filling material is dry, sand the panel down.
Additional layers might need to be applied for a good finish.
If you are using a thin material to cover up the panel, such as
vinyl or grille cloth, then you need a very smooth surface. On the other hand, if you are
using carpet, or padded vinyl, then you don't have to worry about sanding the panel down
Step 4: Covering the panel
Most of the time, spray glue is the adhesive of choice. You can get
a can of 3M (or similar) spray adhesive at any hardware store for about $10. Cut the
covering material (i.e. vinyl) around the shape of the panel, leaving at least a two-inch
overlap. Place the covering material upside down and spray the glue over it. Also spray
the panel. Let sit for about a minute, and place the panel on the covering material,
stretching the fabric over the panel. Use a clean rag on the surface to make sure the
whole top of the panel is in contact with the fabric. Flip the panel over and spray glue
on the overlap, and edges of the panel. Cut the overlap as you go to fit edges and
corners. It is good practice to staple the fabric on the underside, since glue will
sometimes not hold very good when the car gets hot.
Figure on your initial design how you are going to hold the panel.
You do not want to have screws messing up your panel's finish. Pressure fitting
requires a bit of skill, but is the cleanest way to go.
If you are using the panel just to cover up an install, the you
don't need a 3/4" particleboard panel, adding more weight to your car. Plywood will
do just fine. On the other hand, if you are building a sub box, you don't want to use
anything that will bend. Common panel materials are particleboard, MDF, plywood, various
metals, Plexiglas and other plastics, even fiberglass.
To fill gaps and smooth out surfaces, you usually want a material
that will adhere to the panel extremely well, and will be hard. Most installers use Bondo
(car body filler), epoxy (for small fixes), and fiberglass.
There are many materials used to cover up panels. The most popular
are carpet, vinyl, leather and various types of fabrics ranging from speaker cloth to
velour. You can also add padding under the cover material.
There are many materials and finishes available. It just takes
practice to see what material is best for each application. Even though there is no single
way to build a panel, following the above guidelines will give you an idea of the basic
process. The rest you will just have to figure out by trial and error. Even though whole
panels can be build using simple tools such as handsaws and sandpaper, power tools will
greatly reduce fabrication time, especially when sanding.