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How To Make Fiberglass Kick Panels

February 3, 2004

Introduction and Caveats

This is based on my limited fiberglassing experience, so bear with me. I'm still looking for my pictures.

Disclaimer: I am not a professional. I do this as a hobby. I will not be held responsible for any damage to you or your car through negligence or misuse of products, materials, or techniques discussed on this page

Basically, when you're working with fiberglass, you're making a strong plastic and glass composite. (Composite = two materials that work together as a single piece.) The plastic comes in two liquid pieces (resin and hardener). Those two liquids react with each other and harden in place around the glass fiber cloth, which acts as a framing structure for the plastic, which acts like glue to keep the glass fiber cloth in place. It's an intriguing process if you think about it. (If you're a nerd like me, you think about wierd stuff like this all the time.)

Tools and Materials

  • Cheap natural hair paintbrushes
  • Dixie Cups for mixing resin and hardener.
  • Stir-sticks (you can use popsicle sticks if you have any lying around)
  • Fiberglass cloth
  • Fiberglass resin and hardener
  • Fleece
  • Hot Glue and hot glue gun
  • 1/4" dowel
  • wood or MDF for a speaker baffle
  • Hobby knife for cutting the dowel
  • Masking Tape. Lots of it. Buy twice as much as you think you'll need. I'm not kidding.
  • Aluminum foil. Buy the cheap store brand.
  • WD-40. This is used for removing resin from carpet. Keep around for emergencies.
  • Bondo and hardener
  • Spray Adhesive
  • Primer and Paint, Carpet, or Vinyl and Dye.
  • Lacquer thinner (for cleaning excess resin out of the paintbrushes between layers of glass.)

The Eastwood Company has several fiberglass kits that contain cloth, filler, resin, hardener, mixing cups, a paintbrush and even an instructional DVD (or VHS tape) if you would like to buy most of the pieces in one kit. The kits are made by Select Products.

The first step is to cover the area you're going to be working in. That means the kick panel, the carpet in the footwell, and any trim pieces you don't want sticky. Aluminum foil and masking tape works quickly. Overlap the aluminum foil and masking tape to prevent the carpet from soaking up the resin and hardener.

Next, the fun begins: we start working with the fiberglass.

You want to mix the resin and hardener according to the manufacturers directions, so pay attention! If you mix too much hardener, you have potential for fire. This is not to be taken lightly.

On the flip side, if it's mixed too "cold", you'll be waiting for hours for it to cure.

Now, I did mine quick and dirty with one big sheet for the first layer. Ideally, you want to use several two inch by four inch rectangles, dipped in fiberglass resin/hardener and put into place, followed by a natural fiber brush to press out any air bubbles in the resin. You want to overlap these pieces to create some strength in this first layer.

Let the first layer cure for an hour or so. The second layer should be several more pieces dipped in resin and hardener mix and again pushed into place with some natural hair paintbrushes. Use the brush to press out any large air bubbles.

Now comes the tedious part. Trim your backing piece to fit.Drill some screws into the kick panel and attach some backstrap. Bend the backstrap to hold your speaker baffle. You are going to aim them. Bend a piece of backstrap to a 90 degree angle and tape a laser pointer to it and screw it to the baffle. You want to aim the baffles at three different points with the speakers mounted. You want to get close to near perfect imaging.

Most people (myself included) would quit when they got "close enough". Hard-core competitors spend weeks tweaking the position of the kick panels until it is perfect.

The three points you want to aim at are 6" back from the a-pillar base and two inches up the window (on both sides), the dome light, and the opposite side headrest center.

When you're testing how the baffle works, turn off all other speakers. Don't run your subwoofer, don't run any rear fill, don't run any other speakers. Just the speakers in the still-unfinished kick panel.

Choose music that has musicians on opposite sides of the soundstage. This will help you avoid the "rainbow-shaped soundstage" that is common with kick panels. (I couldn't get rid of it, either.) You want everything to be flat and extend past the a-pillars and beyond the windshield, out on the hood. One of the three positions (side window, headrest, and dome light) of the baffle will get you close, and in extremely rare cases, will get you spot on with the first try. Yeah, I spent an hour doing this and was never really satisfied. I got really close once and bumped the driver's side baffle. I couldn't get it straight again.

Okay, you have the baffles aimed properly. Now you want to break out the hot glue gun, a dowel, and a knife to cut the dowel. You're going to support the baffle with the dowels, and temporarily hold them in place with the dowels. Measure the distance from the base piece you made to the panel, trim, fit into place, and hot glue it down. Let it dry completely.

We've just rounded second base. Now, you want to take a piece of mold fabric (a fancy way of saying "fleece") and stretch it over the front of your baffle and around the back side of your floor piece. Use some spray adhesive to hold it into place: spray the baffle first, affix the fleece, then stretch the fleece around back and glue into place.

Get a fresh paintbrush, and mix up lots of resin/hardener. Fleece soaks up more than the fiberglass cloth by a long shot. Use the paintbrush to dab the mix into the cloth. The weight of the resin may cause parts of the fleece to sag. Don't worry, we'll fix that later.

When your fleece and resin has dried, you will re-cut your speaker holes. From the inside of the fleece, you want to apply more fiberglass scraps that have been dipped in resin. This is solely to build strength. Passengers have a way of being rough with custom work.

Now you want to smooth the pieces out. If you have dimples in the fleece from the weight of excessive resin, you want to bondo it. Follow the manufacturer's instructions for Bondo and hardener mix, stir it up with a paint stirrer on a scrap piece of cardboard. Use a bondo spreader to cover the whole piece. Most body fillers are sandable in 20 minutes. Sand it smooth. Your fingers can feel what your eyes can't see. Lightly run your fingers over the piece. Any high spots? How about low spots? You'll either have to add or remove material until it's smooth to your fingers.

You now have three options for finishing your pieces: paint, vinyl, and carpet. Paint is fairly easy: just primer it and paint it to match either your interior or exterior. You must get the surface body-shop smooth, otherwise you'll see every little imperfection in the paint.

Vinyling is difficult. You should invest in a heat gun, vinyl tool, and more glue. The results are definitely worth it. It doesn't need to be perfect, but it wil contour around imperfections underneath it.

Carpeting is the choice if you have large imperfections. The non-reflective property of carpet means that reflections probably won't make your "handywork" blatantly obvious.

Now to sit back and relax. Drill a hole (or two) for wires in the back, and screw the panel to the floor of the car. Make absolutely certain you are not screwing into a wire harness or worse. You should also make certain the panel is aligned properly. Connect your wires to your speakers and finally mount the speakers.

Sit in the driver's seat and enjoy your new kick panels.

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