The most expensive display breakdowns don't happen from drops, but from glue. UV gel that "fills a crack" at home spreads thinner than water: it seeps under the matrix, into flex cable connectors and under the frame, and hardens permanently under ultraviolet light. After this, the display can't be saved by glass replacement or disassembly — the entire display assembly must be replaced.
What exactly breaks
- Matrix. Glue beneath it creates unevenness — a bright spot or distortion appears on the screen that won't disappear.
- Flex cable connectors. Hardened glue in the contacts means the module can't be connected even after cleaning: the contacts must be restored separately.
- Sensors. A drop on the proximity sensor — and the screen won't turn off during a call; on Face ID — and unlocking stops working.
- Speaker and microphone. Glue in the mesh won't wash out, and the sound remains muffled.
Why "filling a crack" doesn't work in principle
UV glue is transparent, but has a different refractive index than Apple glass. Even if it lies flat, the crack will remain visible at an angle, and the surface will become sticky to dust. The glass doesn't become stronger from this: it has already lost its integrity and will crack further from the next impact.
What glue is used in a service center
Not that one. For glass bonding, OCA film is used — a dry layer of optical adhesive of uniform thickness that is laid in a laminator and pressed in an autoclave. UV gel is also available in the workshop, but for something else: it's used to bond camera glass and back covers, where there's no matrix or contacts under the layer.
What to do if you've already applied it
- Don't turn on the UV lamp and don't expose the phone to sunlight. While the glue is still liquid, some of it can still be washed out.
- Don't wipe with a tissue — that spreads it into the cracks.
- Turn off the device and bring it as soon as possible. The difference between "an hour ago" and "yesterday" is critical here.
For technicians who need the right materials: adhesives and adhesive films in the catalog, including adhesive for cameras and filters.