How to Repair Cracked Glass

Updated on 05/25/22

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Crack in Window Glass — the_burtons / Getty Images

Project Overview

Working Time: 15 - 30 mins
Total Time: 1 - 2 hrs

Skill Level: Beginner
Estimated Cost: $5 to $15

Cracked glass is often a fact of life when picture frames, mirrors, kitchen glassware, or door glass meet hard objects. Short cracks can rapidly develop into long ones that spell the end of the entire glass item. But you can quickly and inexpensively repair that glass and stay ahead of complete replacement with epoxy and a utility knife blade.

Fixing Cracked Glass With Two-Part Epoxy

Two-part epoxy consists of a resin and a hardener. Neither will work on its own. You'll need to squirt out the two substances and mix them together. For small repairs, it's best to buy epoxy in a double-cylinder syringe. This syringe regulates the flow of resin and hardener so that they remain within the correct proportion.

Whether gluing the glass in place or working with separate pieces of glass, you won't have to worry about excess epoxy. You'll leave the excess in place and let it fully cure. Once the epoxy has hardened, you will slice it off with a razor blade or utility knife blade.

Types of Cracked Glass That Can be Repaired

Can Be Repaired

Single-pane glass
Mirrors
Glass tiles
Sidelites
Picture glass
Some kitchen glassware

Cannot Be Repaired

Double-pane windows
Microwave doors
Oven doors
Shower or tub glass
Automotive glass

Picture glass, door glass or door sidelites, single-pane windows, mirrors, and glass tile can be repaired with the two-part epoxy method. Kitchen glassware that will not be heated can often be repaired too.

Cracked phone or tablet glass can be repaired to a limited degree. Though the crack will be visible, the fix will prevent the glass from falling out and will stop a crack from lengthening. Plus, it will smooth over the crack and reduce sharp ridges.

Round impact cracks tend to repair best if they are no more than 1-inch diameter. Long cracks should be no more than 12 inches. Glass repair will only work on single pane glass.

Do not repair microwave door glass, double-pane windows, shower or tub door glass, or automotive glass with this method.

Equipment / Tools

Utility knife blade
Nitrile gloves
Wooden craft stick
Safety glasses

Materials

Two-part epoxy
Glass cleaner
Painter's tape

Prepare the Work Area

Lay clean cardboard on the work area. Work in a well-ventilated room. Because you have only about five minutes of working time with epoxy, make sure that you have all of your tools nearby. All tools that you use should be disposable: work surface, gloves, and mixing stick.
Clean and Dry the Glass

The glass must be clean and free of residue for the glue to stick. Separating the broken pieces of glass and cleaning the edges is preferable, if possible. Otherwise, leave the broken pieces together. Let the glass thoroughly dry.

Warning

Handle the glass with care if you decide to separate the pieces for cleaning. Always wear safety glasses.
Prepare the Epoxy

Snap off or cut off the ends of both of the two-part epoxy cylinders. Make sure that both cylinder nozzles are equally open. Squirt the epoxy on a clean working surface such as a paper plate, making sure that both liquids are extruding equally. Thoroughly mix the epoxy with the wooden stick.
Add the Epoxy to the Crack

Glass That Is Separated

If the two pieces of glass are separate, use the wooden stick to daub a small amount of epoxy along the broken edge of one of the pieces. Firmly hold the two pieces of glass together by hand as you add strips of painter's tape to the surface.

Glass That Is Together

If the pieces are together, gently force the epoxy into the crack with the stick, as if buttering bread. It is okay to leave a low hump of epoxy since it aids in the cutting process.
Slice Off Excess Epoxy

Once the epoxy has fully cured. slice off the excess with a loose utility knife blade or razor blade. Slide the blade at a low angle (about 15 degrees) to slice off the epoxy. Slide the blade away from your body. As long as the blade remains flush with the surface of the glass, the epoxy will remain at that level, too.
Clean the Glass

Use paper towels and glass cleaner to clean fingerprints off of the glass and patch.

FAQ

Will the repair to the glass be visible?

Yes. The aim of do-it-yourself glass crack repair is to minimize the appearance of the crack and to contain the crack and prevent it from spreading.
Glass repair will not make the crack completely invisible from all angles. Rather, it is a cosmetic touch-up that only minimizes the visual appearance of the crack. When viewed from certain angles, the repaired crack may not be visible. From other angles, the crack will be visible.
Can windshield glass be repaired?

Windshield repair is not a do-it-yourself project. But professionals can repair windshields. Similar to the procedure described in this guide, a resin is injected into the crack to prevent it from spreading. It may be illegal to drive with a cracked windshield in your area. So, your insurance company can either repair the windshield or replace it entirely.
Can you make a crack in glass disappear?

No, but you can minimize the repair's visibility. Transferring dirt or smudges onto the glass or mirror will make the patch visible. Dirt embedded in the epoxy stays on the glass. So, cleaning the glass is vital. Also, any remaining particles of epoxy will be visible. Make sure that you use a fresh razor blade or utility knife blade and remove all of the epoxy.

When to Call a Professional

A repair person will likely repair the glass with two-part epoxy, too. But with experience, they can likely repair the glass and make it less noticeable (though still not invisible). For sentimental or important items, it's probably best to have a professional repair the glass for you.