Now that the vehicle is protected, there's another thing that needs protection--your health. The most dangerous part of fiberglass work is the inhalation of styrene fumes as well as fiberglass dust. The best way to protect your lungs from this nasty stuff is to work in a well-ventilated area and purchase an organic vapor filter respirator. The most annoying part of working with fiberglass is, of course, the itch. To lessen this problem, always wear latex gloves when handling fiberglass mat and resin. An often overlooked safety precaution is wearing eye protection, not only when grinding and sanding fiberglass, but when pouring, mixing and applying resin.
Everything you need to keep...
Everything you need to keep the fiberglass project from becoming a permanent, unwanted fixture in your car.
RAW MATERIAL
There are many different types of resin available and choosing the right one can be confusing for someone working on their first fiberglass project. For this and most car audio applications, the most sensible resin to use is polyester laminating resin. Casting, finishing, tooling and epoxy resins all have their purposes but are not recommended for this project. Most "laminating resins" are wax free and formulated to stay tacky when exposed to air. They also allow multiple layers to be applied without sanding between layers. A good laminating resin should have the consistency of maple syrup and, with proper catalysis (more on this next time), should have at least 20 to 30 minutes working time at 70F before the resin begins to gel. It should harden within 3 hours and cure within 24 hours.
Another frequent debate is whether to use fiberglass cloth or mat as the strengthening material. For this type of project and most car audio applications, I would only use fiberglass mat. Made of short glass fibers that are held together with an adhesive that dissolves when resin is applied, fiberglass mat has equal strength in all directions. Intended for use in multiple layers (if necessary), it is available in different thicknesses from 0.5 to 3 ounces per square foot. The choice of thickness should depend on the contours of the shape the mat will be applied to. Thicker mat can be built up faster but is difficult or impossible to apply to tight contours and vertical/inverted surfaces. It is best to have different thicknesses of mat available for different projects, but a good all-around mat for these types of projects is 0.75 or 1-ounce mat. Thicker mat can be separated into thinner layers but takes more time during the preparation stage.
To prepare the fiberglass mat, it should be cut into appropriately wide strips (2" to 6", based on the shape and size of the area) then shredded into square or rectangular pieces. Having frayed edges from shredding the mat allows the pieces to be applied with better layering and overall smoothness on different shapes and contours with minimal bubbles and air pockets. Some areas will require that the mat be shredded into triangular or arc- shaped pieces. Having a pair of cheap scissors handy while applying the mat will allow you to custom cut the pieces of mat to best suit the area. Make sure to prepare enough mat before starting the project, so that you won't have to stop to shred more in the middle of applying a batch of resin.
Next time, we'll create our base shell and cover the basics of proper resin application.
Protect yourself from the...
Protect yourself from the hazards of fiberglassing with a charcoal filter respirator, latex (or nitrile) gloves and safety goggles.
Shopping List
Home Improvement Store/ Automotive Paint Supply Store
·Masking tape
·Acetone
·Plastic quart-size cups
(with measurement marks)
·Stir sticks
·Charcoal filter respirator
·Small roller
Home Improvement Store
·3M Super 77 spray glue·Cheap scissors
·Plastic sheeting (2mm thick)
Fiberglass Supply Store
·Polyester laminating resin w/MEKP hardener
·Fiberglass mat
·2" wide bristle brushes
·Latex gloves
Grocery Store
·Heavy-duty aluminum foil
·Paper towels
As the application R&D supervisor at Alpine Electronics from 1995 to 2003, Chris Yato was in charge of creating and managing numerous demo vehicles that served as centerpieces at CES. All of them have been featured in this magazine. He is currently the special projects manager/fabrication trainer for Competition Soundworks in California. E-mail him at chris@teamcsw.com.