Owning a pickup truck has many great benefits, including being able to transport larger cargo more easily. Adding a tonneau cover is one way to maximize the usefulness of your truck bed by protecting your cargo from weather and theft. However, over time tonneau covers can develop issues that require repairing.
One common problem with fiberglass tonneau covers is stress cracks forming. If you notice cracks appearing on your fiberglass tonneau cover, here is a detailed guide on how to properly repair them.
What Causes Stress Cracks in Fiberglass Tonneau Covers?
Fiberglass tonneau covers are known for their durability and rigidity compared to vinyl soft covers. However, they are still prone to developing stress cracks over time. There are a few potential causes for stress cracks in a fiberglass tonneau:
Frequent Opening and Closing
The repeated opening and closing of a fiberglass tonneau cover can eventually lead to cracking. The hinges and panels endure a lot of force and tension when being folded up and laid back down. This constant wear and pressure can cause the material to weaken and crack.
If a heavy object falls onto the tonneau cover, or it sustains an impact from cargo shifting in the truck bed, this sudden force can cause cracks or fractures. Even small impacts that don’t seem serious at first can contribute to cracks over time.
If the fiberglass tonneau cover is not properly supported when upright, the unsupported weight can lead to excessive stress on the panels and hinges. This lack of proper support when open makes the material more prone to cracking.
Extreme Weather Conditions
In very cold climates, the contraction and expansion of the fiberglass from temperature changes can cause it to crack more easily. Extreme heat can also cause warping or cracks. Additionally, hail strikes can fracture fiberglass tonneau covers.
Normal Wear and Tear
Even with proper care and minimal impacts, fiberglass will develop small stress cracks eventually simply from years of use. The many cycles of opening, closing, bumps in the road, and exposure to elements will take their toll over time.
How Serious are Stress Cracks in a Fiberglass Tonneau Cover?
Minor stress cracks in a fiberglass tonneau cover may not be immediately threatening to the structure or function. However, they should still be addressed quickly before expanding into larger cracks or fractures. Once cracks spread across panels, the tonneau cover can lose structural integrity and become prone to buckling or collapsing when weight is applied.
Large cracks or multiple fractures spaced closely together should be repaired immediately. Damaged fiberglass with extensive unsupported sections can fail unexpectedly. Repairing stress cracks early on prevents safety hazards and more expensive repairs later.
Even hairline fractures or surface cracks should be repaired to stop them from spreading deeper through the layers of fiberglass. Avoid delaying minor crack repairs, as they tend to worsen quickly once started. Addressing them when first noticed keeps your tonneau fully functional and avoids premature replacement.
Materials Needed for Fiberglass Tonneau Cover Repair
Repairing stress cracks in a fiberglass tonneau cover requires using a specialized fiberglass repair kit. These kits can be purchased at many auto parts stores, hardware stores, or online. Here are the basic materials included:
- Fiberglass cloth, mat or mesh – This provides the raw fiberglass to rebuild damaged sections. Cloth works for repairs on flat panels, while mats create texture.
- Resin – The liquid resin soaks into the fiberglass cloth and hardens to form the repaired section. Polyester resin is most common.
- Hardener or catalyst – This helps the resin fully harden. It is mixed with the resin prior to applying.
- Mixing containers – Used to properly mix the resin and hardener together before application.
- Stir sticks – Necessary for evenly mixing the resin and hardener.
- Gloves – Wearing protective gloves prevents skin contact with resin.
- Sandpaper – Used to smooth repaired areas once hardened. Start with coarse grit and gradually use finer grit.
- Paint or gelcoat (optional) – For matching the color after repairs.
The specific materials and instructions will vary slightly between brands. Always carefully read the directions before using a fiberglass repair kit.
Step-by-Step Fiberglass Tonneau Cover Repair Instructions
Once you have gathered the necessary fiberglass repair supplies, follow these key steps to properly repair stress cracks:
Clean the Repair Area
Thoroughly clean the area surrounding the cracks with soap and water to remove any dirt, grease or debris. Wipe dry. This helps the repair material adhere properly.
Sand the Damaged Section
Use 100-150 grit sandpaper to rough up the area around cracks. This scratches the surface to improve bonding.
Cut Repair Fabric to Size
Measure and cut fiberglass cloth or mesh to cover and overlap damaged area by 2-3 inches on all sides. Cut several smaller pieces if needed.
Mix Resin and Hardener
Combine resin and hardener according to kit instructions, generally about 3-4% hardener. Stir thoroughly for 2-3 minutes to properly mix.
Apply Resin Mixture
Saturate the repair fabric fully with the resin mixture. Use a brush, roller or squeegee. Work resin into the cracks.
Layer Additional Fabric
For a stronger repair, apply more layers of cloth soaked in resin over the first layer. Let cure slightly between layers.
Allow Repair to Cure
Let the fiberglass repair cure according to specifications. This usually takes several hours or overnight.
Sand and Finish Repaired Area
Once fully cured, use 80-120 grit sandpaper to smooth and shape the repair. Finish with finer 220+ grit sandpaper.
Apply Gelcoat or Paint (Optional)
If needed, apply matching gelcoat or paint to cover repair. Allow time to fully cure.
Be sure to follow all directions provided with your fiberglass repair kit closely. While the process is straightforward, precise mixing and curing times are vital to achieve optimal strength. With care and patience, you can repair stress cracks yourself and extend the life of your fiberglass tonneau cover.
Frequently Asked Questions About Repairing Fiberglass Tonneau Covers
Repairing damaged fiberglass tonneau covers on your own can seem daunting if you’ve never done it before. Here are answers to some frequently asked questions about the process:
Can I Use a Plastic Welder on Fiberglass Cracks?
No, a plastic welder designed for rigid thermoplastics will not properly bond fiberglass. The chemical compositions are different. Repairing fiberglass requires using a specialized epoxy resin.
How Long Does Fiberglass Repair Take to Cure?
Exact curing times depend on the specific products used, but most fiberglass repairs take 2-12 hours to fully harden. Reading the instructions for your repair kit is crucial, as curing times affect strength.
Should I Remove the Tonneau Cover for Easier Repair?
It’s generally easier to remove the tonneau cover from the truck bed to thoroughly repair stress cracks. But if cracks are small, it can be repaired mounted using caution. Completely remove large damaged sections.
Can I Use a Fiberglass Repair Kit on a Molded Tonneau Cover?
Yes, fiberglass kits can repair molded covers, but matching the contoured shape and gelcoated finish can be tricky. Severe cracks on molded covers often require professional help.
How Long Will a Fiberglass Repair Last?
When properly done, fiberglass repairs can last for many years. However, repaired areas are still vulnerable to further cracking if the underlying cause of the damage is not addressed and corrected.
When to Seek Professional Fiberglass Tonneau Cover Repair
While many fiberglass repairs are doable yourself with some effort and patience, there are some instances when you may want to leave it to the professionals:
- Major cracks wider than 1/4 inch
- Numerous cracks across large sections
- Damage along edges and seams
- Matching complex contours and gelcoat finish
- Concerns over repair strength and longevity
- Uncertainty diagnosing the underlying issue
- Lack of time or tools to do it properly yourself
Seeking professional repair assistance not only saves you the hassle and uncertainty of DIY repairs but can provide greater durability. They will also determine if replacement is needed for excessively damaged covers. Leaving cracked fiberglass unmended risks worsening and compromise of the cover. Investing in professional fiberglass tonneau cover repair or replacement pays off through restored security, appearance and performance.
Preventing Future Stress Cracks
Making fiberglass tonneau cover repairs promptly preserves the cover while also minimizing downtime and costs. But the ultimate goal is preventing cracks in the first place. Here are some tips for preventing fiberglass cracks:
- Install support poles when holding the cover upright. Never let it hang unsupported.
- Open and close the cover carefully without slamming.
- Ensure the cover sits flat in the closed position so pooling water can drain off.
- Add protective padding on the inside panels to prevent shifting cargo impact.
- Avoid placing heavy objects on the tonneau cover when closed.
- Use reasonable care when loading, unloading or accessing the truck bed.
- Park in covered areas or use a tonneau cover when possible to minimize sun and weather exposure.
- Check and retighten mounting hardware if the cover lacks proper alignment.
- Wash the cover gently. Do not use harsh chemicals or abrasives.
With attentive care and maintenance, you can maximize the longevity of your fiberglass tonneau cover and avoid untimely cracking or replacement. But even with the most diligent precautions, wear will occur eventually. Knowing how to properly repair stress cracks yourself or seek professional assistance will preserve a safe, functional cover.
Fiberglass tonneau covers enhance your truck’s usefulness through cargo protection and improved aesthetics. But the frequent opening and closing combined with cargo loads, sun exposure, temperature shifts and road hazards make them prone to developing stress cracks over years of use.
Thankfully, restoring structural integrity through fiberglass repairs is a straightforward DIY project. With proper products, preparation and procedures, you can repair cracks as they arise and add more years of service to your tonneau cover.
Understanding what causes the cracks, promptly addressing even minor cracks, using quality repair materials and techniques, and preventing future damage will keep your cover in top shape for the long run.