How to Build a Custom Fiberglass Sub Box?

A custom fiberglass sub box is a speaker enclosure made from fiberglass materials. It is designed to cover and house a subwoofer speaker. It is the perfect way to utilize the trunk space and turn it into an amazing car audio setup. If you are curious to know how to build a fiberglass sub box, here is a complete guide for you:

What are the Materials Required to Make a Fiber Sub Box?

• Subwoofer speaker
• Fiberglass resin and hardener
• Fiberglass mat or cloth
• MDF (Medium-Density Fiberboard) or plywood for mold construction
• Release agent (wax or PVA)
• Mixing containers and stir sticks
• Safety gear (gloves, respirator mask, safety goggles)

Precautions:

1. Always wear safety  gloves, a respirator mask, and safety goggles when working with fiberglass materials to protect yourself from harmful fumes and irritation.
2. Work in a well-ventilated area or outdoors to minimize exposure to fiberglass resin fumes.
3. Avoid direct contact with fiberglass resin as it can cause skin irritation. Use appropriate protective clothing.

Process and Steps :

Step 1: Design and Prepare the Mold

In the first step, you are supposed to create a mold with MDF or plywood that matches the desired shape and size of your subwoofer box. After that apply a release agent (wax or PVA) to the mold surface to prevent the fiberglass from sticking.

Step 2: Cut and Prepare Fiberglass Materials

After creating the mold, cut the fiberglass mat or cloth into manageable pieces that will cover the mold and provide structural strength.

Step 3: Mix and Apply Resin

Here comes the 3rd step, where you have to mix the fiberglass resin with hardener as per manufacturer instructions. The second thing you do in this step is to apply a layer of resin onto the mold surface with  a brush or roller. Experts suggest a well ventilated area for this procedure.

Step 4: Apply Fiberglass Mat

Place the fiberglass mat or cloth onto the wet resin, pressing it gently into place.After that apply additional layers of resin on top of the fiberglass mat, ensuring it saturates the fibers completely.

Step 5: Cure and Remove from Mold

This step involves allowing the fiberglass to cure. The curing process will take several hours to complete. Once the curing process is complete, carefully extract the fiberglass sub box from the mold. Trim away any excessive material and sand down the edges for  a smooth finish. It not only ensures the durability and strength of the sub box but also improves its aesthetic appeal. 

Step 7: Install Subwoofer and Finish

Install the subwoofer speaker into the fiberglass box and make sure it fits perfectly. After that seal the joints with fiberglass resin or silicone sealant to prevent air leaks.

Step 8: Testing

Here comes the moment of truth. Test the subwoofer box with the speaker installed to ensure proper fit and performance.

Final Tips:

• Take your time during each step to ensure proper resin curing and fiberglass layering for a durable and acoustically effective subwoofer box.
• Refer to specific manufacturer instructions for resin mixing ratios and curing times to achieve the best results.

This guide is helpful to create a custom fiberglass sub box that enhances the audio performance and aesthetic appeal of your vehicle or home audio system. Keep the precautions in mind throughout the process to avoid any  mishaps or safety issues.