If you’re into custom cars and like to take on DIY projects then you have to love working with fiberglass. One of the nice things about fiberglass is that it can copy the shape of almost anything and once cured is incredibly strong and lightweight. For decades fabricators have used this idea to make everything conceivable. While there are many ways to get the shape needed, a simple idea is to copy shapes that already exist, even ones found around the house. When designing a panel like the one here on my Mazda “SQ-X”, I like to first start with a sketch to give me a guide as I build the panel. Once you have a design that you feel is worth the time, materials and effort to make, the next step is figuring out the best strategy to make it. If your design has basic shapes in it such as parts of cylinders or spheres, these can be copied from things you may already have laying around the house. The following photos and captions show the construction of the amp trim panel in my Mazda.
1. Here is the basic layout for the amp trim. I wanted two acrylic windows with a painted center piece that would add interest to an otherwise flat boring panel.
2. A 10” diameter cardboard concrete forming tube ( Home Depot under $10 ) will be used to form the vertical portion of the painted trim panel.
3. Simply cut to fit, in this case a ¼ section from the tube provided the basic shape I was looking for.
4. To make a fiberglass copy simply line the tube with tape. Start in the middle and work up the sides so resin doesn’t get under the tape.
5. Next layout 6-8 layers of fiberglass mat. Start by brushing resin on the tape before the 1st layer of mat, then add one layer at a time carefully pushing air bubbles out as you go.
6. Once fully cooled from the catalyst process the fiberglass copy can be removed from the tube. The wax on the tape keeps the resin from sticking.
7. Back in the car the new shape is starting to look at home. At the bottom Duraglass was used to fill gaps.
8. The top of the panel features a viewing window for a large crossover. A part of the same 10” tube was used to make the curved portion that will later connect to the vertical part of the trim panel.
9. In the car the two parts come together at 90 degrees. The problem now is to integrate the two parts which are both from a 10” diameter tube. It would require a 10” diameter sphere. So where might you find that?
10. As it turns out a quick look in the basement yields an old basketball that happens to be exactly the right dimension. Now all we need to do is copy a part of the shape.
11. Simply tape off a portion of the basketball and use a sharpie to draw in the lines for a guide later on.
12. Again using 6 to 8 layers of mat cover the marked portion as evenly as possible.
13 & 14. Once hardened & cooled the new shape can be separated from the basketball. The Sharpie lines transfer to the fiberglass and provide a center guide.
15 & 16. Trim & grind down using the marker line as a center line until you get as close of a fit as possible (Duraglass will fill gaps later).
17 & 18. It is easier to sand and fill this part now before attaching to the panel. Once done, use Duraglass to attach the panel carefully lining it up to the vertical portion.
19 & 20. Back in the car the fit looks nice. The next step is attaching the two with no seams or cracks developing later. Use Kitty hair (behind) and Duraglass (in front) to join the panels. By extending the sides down onto the vertical portion strength is added.
21 & 22. To insure that seams don’t show through later after paint add a couple of thin layers of fiberglass (front & back) to completely hide the seam. Use Duraglass to fill and sand. A strong seamless bond is made.
Part two covers the back side of the trim panel and paint.
