How to Fix a Cracked Window: Techniques and Tips

Having a cracked window can be a frustrating and potentially dangerous situation, but with the right steps, you can often repair the damage without incurring the cost of a new window. This guide covers how to repair both car windshields and home windows, offering various methods based on the type of crack and the window type.

Repairing a Car Windshield Crack

For car windshields with small cracks, you can use a repair kit to make a quick fix. These kits often include a vacuum plunger and a type of cyanoacrylate glue (super glue).

Clean and prepare the area: Start by cleaning the area around the crack thoroughly to ensure there is no dust, debris, or moisture. Use a razor blade or a sharp putty knife to carefully remove any glass fragments.

Apply the glue: As you pull the plunger back, it will suck out any air in the crack. When you release the plunger, the glue will snap and fill the crack from the opening. Aim to fill the crack or slightly larger area to ensure it expands well with rain and heat.

Note: Filling a crack with a repair kit works better if it is around three inches or slightly larger, as smaller cracks might not expand as much and more material may be needed.

Monitor the weather: It's crucial to do this repair on a dry day. Rain and hot days can cause the crack to expand quickly, so the repair should solidify before such conditions occur.

Usually, you won't be able to see the repair once it's complete, but it won't be as good as a new window.

Repairing a Double Pane House Window

For double pane windows, the repair process involves a slightly different approach due to the seal between the glass panes. Here are the steps:

Clean the area: Begin by cleaning the area around the crack with a damp cloth to remove any dust and debris.

Apply silicone: Use a caulk gun or putty knife to apply a thin layer of silicone sealant over the crack. Press firmly to ensure it adheres well.

Allow time to cure: Give the sealant 20 hours to cure. After this period, use a razor knife to scrape off any excess sealant.

Improve air-tightness: It's important to make the repair on a very dry day and to heat the glass on both sides to allow any moisture to escape before sealing. This prevents moisture from forming between the panes, which can cause damage in changing weather conditions.

For severe damage or large cracks, it may be best to replace the window entirely. However, if the crack hasn't separated, you can apply a silicone bead along the joint to hold it in place until you replace the window.

Repairing Larger Cracks and Holes

For larger cracks and holes, the process is more involved:

Prepare the area: Clean the crack thoroughly and remove any fragments.

Apply sealant: Use a putty knife or caulk gun to apply a layer of window sealant or epoxy. Fill the crack and some of the surrounding area to ensure full coverage.

Apply glass tape: Cover the sealant with strong elastic glass tape. Press firmly to adhere the tape.

Repeat for larger cracks: For larger cracks, you may need to apply additional layers of sealant and tape. Wait for each layer to dry as directed before adding another.

Seal with glass compound: Apply auto body filler or glass patching compound over the tape for a permanent solution. Paint or stain the patch to match the window glass.

Alternative solution: Consider using acrylic mirror patch or polycarbonate glass mesh patch, which can be found at auto parts stores or glass shops.

Contact a professional: For severe damage, it's best to contact a glass professional for a permanent repair or replacement.

By following these steps, you can often save on the cost of a new window and keep your home or car safe and secure.