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Patience Is A Virtue | ||||||||||||||||||||
| While working with fiberglass is a rough job, it does have its rewards! | |||||||||||||||||||||
| by Matt Borgardt | |||||||||||||||||||||
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Working on fiberglass is a long and tedious job — you have to wait and twiddle your thumbs while parts dry. But, in the end, your idea and imagination comes to form. This is why creating fiberglass enclosures and amp racks can be so rewarding. In the following articles, I’ll be talking mainly about the sub enclosure in Rob Hephner’s Ford Focus, this way I can show you the details of the design. As I did last time, I’d like to begin by talking about shop safety. Remember to read about, and understand, all the tools that you’ll be using. This will reduce any harm to your ten best friends. And, most of all, wear your safety glasses at all times. In my last article, I left having not removed the newly laid fiberglass wall. After two days of drying, I removed the mold by pulling it away from the body. If you have an air compressor, it’s a good idea to blow air in between the fiberglass and the steel body of the car to make the removal a little easier. Once this is done, I like to see if I have any holes or defects in the new mold (Photo 1). The next major step in the design phase I needed to work out was finding the best square area in the trunk — the whole back end will be based off of this area. Using the sides of the car, and measuring back to the seat, I was able to tape off a straight line — this line will act as my reference to square in the car (Photo 2).
Next was to create a pattern of the floor and side wall for the base of the design. This was achieved by using an old trick of the trade. Using a 1/4-inch thick straight piece of wood or plexi, sharpen the end to a round point (Photo 3). Find the middle of your handy new tool and drill some holes wide enough for a pencil. Next, place your cardboard down on the floor and square it to the tape line. Take your handy duplicator and follow the vehicle’s sidewall pattern, while, at the same time, marking your cut line with your pencil (Photo 4).
After you’ve created your pattern, you’ll need to cut out the design and test its fit (Photos 5 and 6). In most cases, you’ll need to do some reforming of your jig, but this is easy since your pattern is made of cardboard. There are two important rules that you must remember when doing pattern duplication: the cardboard pattern must be created at the level at which the final piece is to be mated to the side wall. If you don’t follow this rule, you’ll find that your pattern will not mate up at all. The other rule of thumb is to make sure that your duplicator tool must not exceed 1/4-inch wide. This ensures that the intersection points of the side wall are accurately created, allowing you to make a more accurate copy.
After repeating the step above for all the base parts for the Focus (Photo 7), and making sure that the design was completely square in the back, we’re able to work on to the next step. Again, I like to use cardboard so that I can look at the install and make modifications if needed. As you can see in Photo 8, the mid section will be a triangular shape. When designing a install, I take visual cues from the car. In the case of the Focus, the designer calls it a “knife edge design” in which you go from a smooth surface to 45-degree cuts. This design theory — going from square to round — will be carried throughout the entire concept. The back end will also be modular in design so all the parts can be easily removed for painting. This also allows Rob to easily take the system apart if there was ever a problem with the system.
Now that the cardboard is all cut to fit it, we need to transfer the patterns to the wood and cut them out. I decided on Baltic birch as the base material for the install — I like the strength and “routerability” of the wood. In Photo 9, the base boards have been routed and some jigsaw action was needed for final fitting. Placed back in the car, the parts are lined up and work can be done on the center section. Photo 10 shows the pillars that I needed to build into the design. I had to design these pillars for several reasons. First, when the fiberglass shrinks, the pillars help add structural stability to the individual parts. This keeps them from pulling apart from one another as the fiberglass dries. The right-angle joints give me the stability I need. We also needed a place where the joints from the center section could come apart from the amp rack and subwoofer enclosures. I should also point out that I’ll be using polyurethane glue for all the wooden joints — I like this glue for its sheer strength. In the past, I’ve had joint failures due to shrinking of the fiberglass on large parts, and the polyurethane helps alleviate that!
Next time, we’ll be covering the fiber glassing of the sub enclosure and how we made the install in three parts so it was easier to build. Remember, you can talk to me on the Forums at www.carsound.com under “ Matt Borgardt on Fabrication.” |
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