A bullseye and a star break are different failures with different repair paths: a bullseye is a round impact crater with a cone of fractured glass under it, while a star break is a set of radial legs running outward from the impact point. If you are deciding whether to attempt a repair or call a shop, look at the legs. A bullseye with no radiating cracks is the one you can often fill yourself; anything with legs longer than a thumbnail, or legs that reach the edge of the windshield, is a replacement conversation. Combination breaks, which carry both a crushed center and radiating legs, sit in between and are the ones people most often misjudge.
Learn to read the impact point before you touch anything
Clean the spot with a dry cloth and look at it from the inside of the glass, not the outside. The pit on the exterior surface is only the entry wound. What matters is the shape of the fracture underneath, and it reads very differently depending on which side you view it from.
A bullseye looks like a small circular crater with a dark ring around it and a cone-shaped plug of broken glass beneath the surface. There are no legs. The impact usually comes from a rounded object — a bolt, a ball bearing, a piece of gravel with a blunt face. Because the damage is contained, resin can be pushed into the cone and cured, and the repair is often close to invisible.
A star break has a small pit at the center and multiple cracks radiating outward like spokes. The legs are the defining feature, and their length determines everything. Short legs that stay within a coin-sized area are still repairable. Legs that keep running, or that have already reached a crack or the edge of the glass, mean the structural integrity of that area is gone.
A combination break has both: a bullseye-style crushed center plus radiating legs. These are common from highway debris because the impact is both blunt and fast. They take longer to fill, they need the legs worked individually, and they are the type most likely to spread while you are working on them.
One thing that trips people up: a bullseye viewed from outside can look like a star break because the ring catches light. Always check from both sides before you decide what you are dealing with.
Decide whether it is a repair or a replacement
Size and location decide this, not the name of the break. Most repair guidance draws the line at damage larger than a certain diameter, at cracks that reach the edge of the windshield, and at anything directly in the driver's primary line of sight. A bullseye the size of a pencil eraser in the passenger-side lower corner is a straightforward repair. The same bullseye sitting directly in front of the driver is often replaced anyway, because even a good repair leaves a visible optical distortion that the driver stares through for the life of the car.
Legs change the calculus faster than diameter does. A star break with three short legs may cover less area than a large bullseye, but each leg is a stress concentrator. Temperature swings do the rest. A windshield that sits in the sun and then gets hit with air conditioning, or a cold morning followed by a defroster, flexes the glass and the legs grow.
Use this as a working checklist:
- Bullseye with no legs, smaller than a coin, away from the driver's sight line: good repair candidate.
- Star break with legs shorter than a thumbnail and no leg touching the edge: repairable, but do it soon.
- Combination break with a crushed center and multiple legs: repairable if it is small and off to the side, otherwise replace.
- Any break with a leg running to the edge of the glass, or a crack longer than a few inches: replace.
- Damage in the driver's primary viewing area: replace, even if the size suggests otherwise.
The honest trade-off is cost against appearance. A repair kit is cheap and takes under an hour. A replacement is not, and on many modern cars it also means recalibrating the driver-assistance camera behind the glass, which is a separate charge and a separate appointment. That calibration is the reason a lot of people who could replace choose to repair instead.
Work the resin in the right sequence for each type
Resin fills a bullseye in one pass; a star break needs the legs fed individually; a combination break needs the center stabilized before the legs are touched. Doing it in the wrong order is how a repairable break becomes a replacement.
For a bullseye, park out of direct sun, clean the pit, and use a bridge or injector to press resin into the cone. The air trapped in the cone has to come out before the resin goes in, which is why the better kits include a vacuum step. Cycle pressure and vacuum a few times, then cure with the supplied UV film and sunlight or a curing lamp. Scrape the excess flush with a razor blade held at a shallow angle.
For a star break, the legs are the problem. Resin has to travel down each one, and a leg that has closed up will not accept it. Work from the center outward, applying pressure at the pit and letting the resin chase the legs. If a leg does not fill, stop and reassess — forcing it usually extends it.
For a combination break, treat it as a bullseye first. Fill and cure the crushed center so the legs stop moving, then go after the legs. This is slower and the result is usually more visible than a simple bullseye repair, but it holds.
Temperature matters more than most guides admit. Cold glass is brittle and resin flows slowly; hot glass in direct sun can cure the resin before it reaches the bottom of the break. Work in shade, and if the windshield is hot to the touch, let it cool first.
Stop the damage from spreading while you wait
Cover the pit with a piece of clear tape immediately, whether or not you plan to repair it yourself. Tape keeps water, dirt and car-wash soap out of the fracture, and contamination is what makes a later repair look cloudy or fail to bond.
Avoid the things that flex the glass. Do not slam the doors. Do not run the defroster on high directly at the damaged area. Do not park in direct sun if you can avoid it, and do not pour hot water on a cold windshield to clear ice. Each of these is a temperature or pressure cycle, and each one gives the legs a chance to run.
If you are going to repair it, do it within a few days. A break that is stable today is not stable indefinitely — vibration from driving, and the normal flex of the body over bumps, works on it continuously. The smaller and fresher the damage when you start, the better the result.
What you should not do is guess at the size of the problem from the driver's seat. Get out, look at the glass from both sides in good light, and identify whether you are looking at a crater, legs, or both. That single check tells you whether you are buying a repair kit or booking a replacement, and it takes less time than reading the instructions on either.