Windscreen Scratches - Can their effect be lessened?

PostPost by: AlfaLofa » Sat Sep 13, 2014 1:30 pm

Are there any recommendations on how to lessen the effect of windscreen scratches?
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PostPost by: Grizzly » Sat Sep 13, 2014 2:03 pm

It depends on how bad they are tbh.

You can buy kits to polish glass but for the expense there not really worth it and very time consuming. I worked in a Bodyshop and we would often get a scenario where wiper blade had been damaged etc so had scratched a screen, in that case we would get AutoGlass out who would machine polish the screen (cost between ?20-50) but even though the scratch was not obvious you could see the wobble in the screen where the material had been removed.

So for me if its some thing you can get your nail into save the money and get a new screen but if they are shallow / more cosmetic scratches contact the local screen people (its a big thing at the moment repairing screens with Scratches,Chips etc) see what they have to say.
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PostPost by: Plus 2 » Sun Sep 14, 2014 5:08 am

Steve,

I agree with what grizzly says so what sort of scratches on the screen are you having to deal with.

The most common problems are surface scratches on the glass that follow the arc of the windscreen wipe.

The main causes are due to the wiper arm itself being not set correctly in line with the windscreen glass or it is worn. The blades usually get changed often but the arms get left. These wiper blades with universal plastic components sold as a fit ALL don't help either.

I the blades are of the original metal/stainless Lucas/speedwipe type it really is essential these are set and lined up correctly.

So before spending out check them out. The damage to the screen is mainly done by the tangs on the blade that wrap over the metal strips that slide into the rubber insert.

Unless the blade is absolutely parallel to the glass then on one side of the wipe action it will drag on the screen. You can easily check this setting and any free play just by holding the area where the arm joins the blade. Easier to do in a mid position so start the car and wipers then cut the ignition when the wipers are mid point. Just rock the wiper arm side to side, there will be enough free play in the wheelboxes and observe how close the metal part of the wiper blade is to the glass on each side.

Never assume new wipers and arms are going to be set correctly. All that is needed is to twist slightly the long part of the arm that fits into the blade close to the connection so when you rock the blade on the screen it is even clearance from the metal tangs to the glass on both sides.

Always then avoid wiping too much on a dry screen as this causes more drag and twists the blade on the arm more which again may cause contact of the steel to the glass.

Lesser problems can result from sand/grit having got trapped during wiping and this can be an issue for people who live close to the seaside and those that park their car overnight close to a brick wall.

Again common issue here is drivers door window vertical scratches. Grit comes off the roof tiles or weathers off the brickface drops onto the sideglass and gets trapped in the small gap on the outside of the glass where it faces to the exterior lower rubber seal. Glass is then lowered and the grit particles get impregnated into the rubber and act as a piece of sandpaper thereafter. Not much really one can do when a car is not garaged or covered.

OK now cause/prevention is dealt with onto the repair.

Forget deep scratches in the windscreen if in the eyeline of the driver. Any repair will cause visual distortion as grizzly rightly points out and on deep scratches will be irritating to drive with the distortion. I can't even wear varifocals or bifocals as the viewing through the lenses makes me feel sick. You will always recognise me though as I wear one pair of glasses and another always hanging from my kneck. Thankfully only suffering myopia in later years but have to put one pair over the other for close up reading.

However if the scratches are just surface scuffs these can be visually improved with no problem for viewing through the glass.

Yes kits are available but expensive and you only get a very small quantity of 'paste' and usually a few cloths and a small tool for the drill.

The common 'paste' used is cerium oxide and it is what is used to polish pebbles and gemstones.

Where the scratches are just surface it can be cheaper to just buy small packs of the paste/powder online (search for gemstone pebble polishing hobbyists) and I suggest a medium and fine grade. Provide your own cloths and then a lot of elbow grease in small circular motions can polish light surface marks out.

Anything deep requires the use of a drill and wheel with special pads but with the screen being laminated the heat produced can crack the glass so has to be done cautiously spraying water regularly to cool and reduce the friction.

Again if really bad scratches check out your insurance excess and have the screen replaced it may only be ?50-100. PM me I will explain the process how to get this done :wink:

However unless you address the route cause a new screen can get scratched within 10 minutes use of wipers being badly set.

Hope this helps.

All the best

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PostPost by: AlfaLofa » Sun Sep 14, 2014 6:55 am

Steve and Grizzly - thank you for your replies.

I thought I had described the marks in a second posting last night.

I must have hit the wrong button!

They are "circular" scratches caused by grit trapped in a cleaning cloth.

The gemstone paste sounds like an excellent recommendation - I'll give it a go.
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PostPost by: Jentwistle3 » Sun Sep 14, 2014 11:36 am

I have had some success with the glass polish from Griot and Eastwood. It is VERY time consuming.
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PostPost by: Plus 2 » Sun Sep 14, 2014 11:37 am

Steve,

Take a look then at this thread, it may be useful before you decide what to do. Also if you search 'youtube glass scratch removal with cerium oxide' there are lots of examples before and after to be found that may help you decide what tools you need to get.

http://www.meguiarsonline.com/forums/sh ... Correction.

All the best

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