How Are Windscreens Repaired?

By 12/09/2021 October 11th, 2021 No Comments

In the UK, auto glaziers provide windscreen repair services that restore the visibility and structural integrity of your windscreen so that it looks just like new. How do they repair damaged windscreens? Let’s have a look at windscreen repairs in more detail:

How Are Windscreens Repaired? myWindscreenTypes of windscreen damage

There are many different types of damage that a windscreen can sustain, some severe, some less severe but no less important to have repaired. The big reason for this is that over time, even small cracks or stone chips will expand and grow with time and vibration, perhaps making your vehicle completely unsafe to operate.

There are some different words often used to categorise windscreen damage, such as:

  • Cracks: simply a cracked line extending along the windscreen. Can be simple cracks, intersecting, or complex cracks extending to the edges of the windscreen;
  • Stone chips: a common type of damage, stone chips are so named because often pebbles or small stones are kicked up and flung into the windscreen, leaving behind a circular section of damage;
  • Bullseyes: a type of stone chip that leaves behind a small ‘eye’ at the centre, often a section of glass knocked out;
  • Star crack: a combination of a stone chip with cracks radiating outwards;
  • Half-moon: essentially a stone chip, only in a half-circular form;
  • Combination cracks: there are many types of combination cracks possible, often given catchy names like floater cracks, clover leaf cracks, bee wing cracks, and so on.

Can any windscreen be repaired?

Not all windscreens can be repaired. If the windscreen is severely damaged, it will need to be replaced, which tends to cost more. That’s why we recommend motorists have their windscreens repaired sooner rather than later (when it’s too late).

Damage that cannot be repaired include:

  • Damage protruding to the inside of the windscreen
  • Damage to internal car sensors (for ADAS windscreen systems)
  • Complex, spiderweb-like cracks
  • Long cracks and intersecting cracks
  • Cracks extending to the edges of the windscreen

Can I repair a windscreen myself?

Yes, it’s possible to DIY windscreen repairs. DIY windscreen repair kits can cost as little as £10 and often claim to save you time and money. That’s all well and good, but it begs a bigger question: should you be leaving your safety (and that of your passengers) to a tenner?

If you plan to take this course of action, please be aware that there are risks involved. DIY kits can save you money, but if you lack the proper tools and techniques (those that come with these kits are certainly not as high-quality as what an automotive glazier would use), the job might take far longer than anticipated and leave your windscreen in a worse condition than when you started. In brief, leave this job to a professional.

Windscreen impairment and the MOT

A big reason to have your windscreen repaired and free of impairments is to pass your yearly MOT test. Driving with a damaged windscreen – depending on the location, size, and severity of the damage – may be illegal and lead to citations and three penalty points from your driving license.

The MOT considers any damage in excess of 10mm in size (i.e. stone chips or cracks) to be an automatic FAIL if the damage is found within the driver’s immediate field of vision (zone A in the diagram below).

Furthermore, any damage in excess of 40mm in size within zone B or significant scratches that impair the driver’s vision will likewise lead to an automatic fail.

How Are Windscreens Repaired? myWindscreen

How professional auto glaziers repair windscreens

Now for the meat and potatoes of how windscreens are generally repaired. Naturally, the severity and scope of the damage will affect the process and how long it takes, but generally speaking, half an hour is all that’s needed for a professional automotive glazier to repair a stone chip or small crack.

Most automotive glaziers follow the below rubric:

  1. Cleaning: first and foremost, any small pieces of glass around the stone chip must be removed. Dirt and debris that may have entered the chip must also be cleared out thoroughly. This is often done with a fine razor scraper gently applied to the damaged area. In some cases, glaziers will apply just a little pressure, which extends the damage marginally but permits the natural crack joints to align which can make the following steps easier.
  2. Create a vacuum: in order to apply the resin compound to the crack and to have it thoroughly filled in, an air vacuum needs to be made. This is done with professional tools that often have suction cups attached to one end. The suction cup is applied directly over the damaged area and creates an airtight seal which is essential for the proper application of the resin, which is an anaerobic substance (i.e. it may cure improperly if air is permitted to remain).
  3. Apply resin to the chip: an applicator is then used to inject a clear resin compound directly into the damaged area. This is often done gradually and multiple applications may be necessary to ensure that the entire crack is filled in. Professional glaziers use high-quality resin compounds designed to industry standards.
  4. Curing: the resin then needs to cure before achieving peak structural stability. Automotive glaziers use handheld UV lights to speed up the curing process, thus making it possible to get back on the road within half an hour or so.
  5. Finishing touches: depending on the technician and the type of repair needed, another resin compound may be used as a coating over the crack, which itself must be cured and subsequently polished. The excess resin must be cleared away to create a seamless surface for your windscreen wipers.

This process can be repeated over and over for multiple stone chips or small cracks until your windscreen looks just like new.

Get your windscreen repaired today

We get it – calling an auto glazier isn’t a call you probably want to make, but rather one you have to make if you’ve ever woken up to a shattered windscreen or need a big old stone chip repaired.

That’s where myWindscreen comes in. We make it hassle-free, simple, and easy to find reputable, affordable, and independent auto glaziers in your area, all across the UK.