How to Repair a Windscreen Stone Chip Perfectly
This windscreen chip repair was just off the windscreen A-zone on a new VW Golf for a local company in Newton Abbot.
As you can see from the picture it was a particularly nasty windscreen chip with 5 cracks (live vents) radiating from the initial impact. This type of repair can be extremely difficult as there is a high risk the live vents will start to travel and necessitate a new windscreen.
Normally with a windscreen chip repair it is common to open up the chip with a scribe or impactor, this requires a little bit of pressure on the chip and would’ve been too risky. In this instance it was far safer to gently drill the stone chip with a glass drill burr, this puts no real pressure on the chip and opens it up enough to inject the windscreen repair resin.
After drilling the chip and injecting the resin it becomes a waiting game to see how well the resin flows into the cracks. Due to the low temperature this time of year the resin didn’t work very well, flowing about 1cm from the chip centre and failing to fill the live vents which were about 2cm in length. At this point the glass needed heat to enable the resin to flow correctly, localised heat carries a high risk of causing the live vents to travel as does intense heat over the whole screen with the cold outside. So we ran the engine and initially started to warm the lower half of the windscreen, worried about the risk if the chip cracking further we switched the heater to the floor area and slowly warmed the interior of the car which results in the glass warming slower but more uniformly. Anyone who waves a cigarette lighter around the stone chip on the inside will generally fail to get a decent repair and once the windscreen cools the chip will almost always reappear as they drive off down the road!
Eventually after around 20 minutes instead of the usual 10 mins the live vents filled with resin and just a tiny sliver of the original crack was left. With the temperature and chip stable we gave the chip another 10 minutes and the result – A Perfect Windscreen Chip Repair.
Windscreen Chip before:
Windscreen Chip after Repair: