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I sort of figured this article would be relevant for this group, even thought he specific car I am working on is an Alfa Romeo. I hope this helps explain how we can do something about those scratches and sand pits that mar our windows.
Polishing out window scratches.
Our Alfa Romeo Montreal came to us with quite evidence of having been driven to the beach. Often. Lots of sand in various places. One of the impacts was lots of scratches on the side windows, partly from sand getting down into the seals, and part because it looked like someone used a card or something to remove ice and got sand under the card near the seals (that had sand in them). Then, if that wasn’t enough – the rear glass had lots of scratches – like the owners had lots of diamond rings. At least there were lots of scratches.
ARGH!
With that reality I proceeded to do what I could to polish out the more egregious flaws. And learned a lot about polishing glass.
Whilst it seems it is easy to scratch glass, not so much getting rid of the scratches.
There are many, many polishing options out there. And lots of grits to choose from.
A good start in polishing glass is to keep everything that you are polishing wet - it just works better. And, first and foremost – it will give you a chance to spread water everywhere – walls, pants, windows, anywhere it can be sprayed will be sprayed. You need to keep adding water to keep from drying out the pad, even more to be flung off into the surroundings.
It’s easy to remove a deep scratch with a coarse grit – say 600 or 800. Then you move up to a 1200, followed by 1800, then 2400, then 3,000, at which point you figure out there are still scratches from the 600 or 800. Hmmm. So, back to 1200, etc. Do that cycle 2 or 3 times and you begin to question the whole process. But, later (rather than sooner), you will get to the point you can move up to 5000 grit and wow – the world is a great place – serious crystal-clear glass.
Hmm – I mentioned 5000 grit - which can either be a 5000-grit polishing pad or a felt pad with cerium oxide powder - which is the equivalent of a 5000-grit polishing pad.
I have found that using cerium oxide powder when doing anything finer than 1500 grit is a big help – the powder forms a paste which doesn’t fly off as easily. Of course, when you add a bit too much water - you paint everything around you with cerium oxide. Grits less than 1500 cut pretty quickly so not so much of concern with the water getting away.
I started my polishing on a side window, getting rid of the deeper scratches with 800 grit pads. Then began working toward finer grits to get rid of the 800 grit scratches. After making a huge mess I started looking for a replacement window. And shifted to the rear window. But only using finer grits – limiting the damage I could do.
After doing the rear glass from our Montreal, I’ve pretty much concluded it is better to use finer grits and accept it will take a while to remove a scratch. At least you only have to do it once – then go finer and finer till you are polishing with 5000 or cerium oxide. Overall, I think it saves time to just go with finer grits.
In my experimenting I found 4 ways to scratch glass. There’s the pretty standard polishing pads that are made up of lots of little rectangles that are impregnated with grit. (Search “Diamond Polishing Pads” on Amazon) Picture 2 below
I have them, I don’t like them. They take forever, compared to the next option – Sponge Fiber Diamond Polishing Pads (search “Sponge Fiber Diamond Polishing Pad” on Amazon) Picture 3 below.
I like these because the “sponge” fibers wick up a bit of water so they stay wet a lot better. The water caries cerium oxide up into the pad, which keeps it from all immediately depositing on the front of your pants. Instead, it flies off slowly – same amount on your belt buckle, but it takes longer.
In my experience, the sponge pads cut a heck of a lot faster than the solid pads.
Next are the felt pads that you use when polishing with cerium oxide. They work great, but the sponge fiber pads work faster. (Search “Felt Polishing Pad” on Amazon)
The fourth option comes from Eastwood. They offer a kit that contains 3 adhesive-backed film discs, a pad for them, and a wool polishing pad along with some cerium oxide powder. > Glass Polishing Kit for Deep Scratches <
I used this kit to polish out scratches in the side windows of our Pantera. Pluses are the three grades of discs – they work. Negative is the 3-inch diameters – this makes it a bit easier to dish the glass and create optical distortion. If you just have one scratch, and it isn’t too deep – this is a good option. But a little pricey.
For a long time, Eastwood didn’t offer replacement abrasive film: Use it long enough and it does wear out. Replacement abrasive film is back in stock and reasonably priced. Until you pay for shipping. Sad, it would go in a business envelope, but they want $10.77 to ship.
OK – it should be obvious by now that you need to set up a work area that is surrounded by a wall of cardboard to catch all the wet stuff that is going to get flung off of the polishing work. Picture one below is a shot of my work area – after doing the back glass from our Alfa Romeo Montreal.
It’s a pretty big area because the back glass is pretty darned big. I could use a smaller work space for the side glass, but the extra space is handy for the tools when polishing away.
How long did it take to clean up most of the scratches in the back glass? I’m thinking 30 or 40 hours. As in, many, many 1, 2 or 3 hour sessions.
Note – set up your workspace so you are not bent over – your back will really appreciate you.
In the first picture below, you will perhaps note the squeegee and the water bottles. And the splatter. You might also note what looks like red lines on the glass – they are on the back-side of the glass – showing me where there are scratches I need to remove.
Something else to keep in mind – if you start out with a coarse grit, you will hopefully keep the sanded area to a fairly small section right around the scratch. Each successive grit as you go finer will need to cover a larger area – to make sure you remove all the scratches you created as well as to blend into the surrounding glass. This truly gets old after a while.
I also learned, after spraying lots of cerium oxide on the surrounding environment, that using a polisher that has a random-orbit option with free spin, instead of forced spin is a good idea. I started out with power drills and a conventional buffer. Danged, those suckers sling mud. The Makita random dual action random orbit polisher I ended up with works really well. It also doesn't drag any coarse particle that might end up on your glass across the glass in a nice, wide arc.
My recommendation is to either go with the Eastwood kit or focus on just using sponge fiber pads with grits over 1800. Yes, it might seem to take longer, but it is so much easier to remove the fine scratches from 1800 then from 800.
Flip side, if what you want to do is clean up some of the fine pits in your windshield to get rid of some of the glare when driving into the sun, you might just buy a 5000 grit sponge fiber pad and use it to do some polishing. It works without cerium oxide, at which point you are just slinging water with very little bits of polished off glass. Makes clean-up a lot easier.
Keep the windshield wet with a spray bottle, and spend as long as you want. As you start to polish out the little pits the edges of the pits will round off, which will significantly cut down on the glare: You don’t need to remove the entire pit to make a big difference. And, at the same time you can wipe out the traces on the windshield from the wipers – provided they aren’t too deep.
With the back window cleaned up I tackled the side window I had buggered. And was able to clean it up, and cancel my purchase of windows I had found in Europe.
Was it worth it? A resounding yes. Whilst I could have accepted the scratched glass, I will be much happier seeing the crystal-sharp results. And, hey, just exactly where would one find good rear hatch glass for a Montreal?
Polishing out window scratches.
Our Alfa Romeo Montreal came to us with quite evidence of having been driven to the beach. Often. Lots of sand in various places. One of the impacts was lots of scratches on the side windows, partly from sand getting down into the seals, and part because it looked like someone used a card or something to remove ice and got sand under the card near the seals (that had sand in them). Then, if that wasn’t enough – the rear glass had lots of scratches – like the owners had lots of diamond rings. At least there were lots of scratches.
ARGH!
With that reality I proceeded to do what I could to polish out the more egregious flaws. And learned a lot about polishing glass.
Whilst it seems it is easy to scratch glass, not so much getting rid of the scratches.
There are many, many polishing options out there. And lots of grits to choose from.
A good start in polishing glass is to keep everything that you are polishing wet - it just works better. And, first and foremost – it will give you a chance to spread water everywhere – walls, pants, windows, anywhere it can be sprayed will be sprayed. You need to keep adding water to keep from drying out the pad, even more to be flung off into the surroundings.
It’s easy to remove a deep scratch with a coarse grit – say 600 or 800. Then you move up to a 1200, followed by 1800, then 2400, then 3,000, at which point you figure out there are still scratches from the 600 or 800. Hmmm. So, back to 1200, etc. Do that cycle 2 or 3 times and you begin to question the whole process. But, later (rather than sooner), you will get to the point you can move up to 5000 grit and wow – the world is a great place – serious crystal-clear glass.
Hmm – I mentioned 5000 grit - which can either be a 5000-grit polishing pad or a felt pad with cerium oxide powder - which is the equivalent of a 5000-grit polishing pad.
I have found that using cerium oxide powder when doing anything finer than 1500 grit is a big help – the powder forms a paste which doesn’t fly off as easily. Of course, when you add a bit too much water - you paint everything around you with cerium oxide. Grits less than 1500 cut pretty quickly so not so much of concern with the water getting away.
I started my polishing on a side window, getting rid of the deeper scratches with 800 grit pads. Then began working toward finer grits to get rid of the 800 grit scratches. After making a huge mess I started looking for a replacement window. And shifted to the rear window. But only using finer grits – limiting the damage I could do.
After doing the rear glass from our Montreal, I’ve pretty much concluded it is better to use finer grits and accept it will take a while to remove a scratch. At least you only have to do it once – then go finer and finer till you are polishing with 5000 or cerium oxide. Overall, I think it saves time to just go with finer grits.
In my experimenting I found 4 ways to scratch glass. There’s the pretty standard polishing pads that are made up of lots of little rectangles that are impregnated with grit. (Search “Diamond Polishing Pads” on Amazon) Picture 2 below
I have them, I don’t like them. They take forever, compared to the next option – Sponge Fiber Diamond Polishing Pads (search “Sponge Fiber Diamond Polishing Pad” on Amazon) Picture 3 below.
I like these because the “sponge” fibers wick up a bit of water so they stay wet a lot better. The water caries cerium oxide up into the pad, which keeps it from all immediately depositing on the front of your pants. Instead, it flies off slowly – same amount on your belt buckle, but it takes longer.
In my experience, the sponge pads cut a heck of a lot faster than the solid pads.
Next are the felt pads that you use when polishing with cerium oxide. They work great, but the sponge fiber pads work faster. (Search “Felt Polishing Pad” on Amazon)
The fourth option comes from Eastwood. They offer a kit that contains 3 adhesive-backed film discs, a pad for them, and a wool polishing pad along with some cerium oxide powder. > Glass Polishing Kit for Deep Scratches <
I used this kit to polish out scratches in the side windows of our Pantera. Pluses are the three grades of discs – they work. Negative is the 3-inch diameters – this makes it a bit easier to dish the glass and create optical distortion. If you just have one scratch, and it isn’t too deep – this is a good option. But a little pricey.
For a long time, Eastwood didn’t offer replacement abrasive film: Use it long enough and it does wear out. Replacement abrasive film is back in stock and reasonably priced. Until you pay for shipping. Sad, it would go in a business envelope, but they want $10.77 to ship.
OK – it should be obvious by now that you need to set up a work area that is surrounded by a wall of cardboard to catch all the wet stuff that is going to get flung off of the polishing work. Picture one below is a shot of my work area – after doing the back glass from our Alfa Romeo Montreal.
It’s a pretty big area because the back glass is pretty darned big. I could use a smaller work space for the side glass, but the extra space is handy for the tools when polishing away.
How long did it take to clean up most of the scratches in the back glass? I’m thinking 30 or 40 hours. As in, many, many 1, 2 or 3 hour sessions.
Note – set up your workspace so you are not bent over – your back will really appreciate you.
In the first picture below, you will perhaps note the squeegee and the water bottles. And the splatter. You might also note what looks like red lines on the glass – they are on the back-side of the glass – showing me where there are scratches I need to remove.
Something else to keep in mind – if you start out with a coarse grit, you will hopefully keep the sanded area to a fairly small section right around the scratch. Each successive grit as you go finer will need to cover a larger area – to make sure you remove all the scratches you created as well as to blend into the surrounding glass. This truly gets old after a while.
I also learned, after spraying lots of cerium oxide on the surrounding environment, that using a polisher that has a random-orbit option with free spin, instead of forced spin is a good idea. I started out with power drills and a conventional buffer. Danged, those suckers sling mud. The Makita random dual action random orbit polisher I ended up with works really well. It also doesn't drag any coarse particle that might end up on your glass across the glass in a nice, wide arc.
My recommendation is to either go with the Eastwood kit or focus on just using sponge fiber pads with grits over 1800. Yes, it might seem to take longer, but it is so much easier to remove the fine scratches from 1800 then from 800.
Flip side, if what you want to do is clean up some of the fine pits in your windshield to get rid of some of the glare when driving into the sun, you might just buy a 5000 grit sponge fiber pad and use it to do some polishing. It works without cerium oxide, at which point you are just slinging water with very little bits of polished off glass. Makes clean-up a lot easier.
Keep the windshield wet with a spray bottle, and spend as long as you want. As you start to polish out the little pits the edges of the pits will round off, which will significantly cut down on the glare: You don’t need to remove the entire pit to make a big difference. And, at the same time you can wipe out the traces on the windshield from the wipers – provided they aren’t too deep.
With the back window cleaned up I tackled the side window I had buggered. And was able to clean it up, and cancel my purchase of windows I had found in Europe.
Was it worth it? A resounding yes. Whilst I could have accepted the scratched glass, I will be much happier seeing the crystal-sharp results. And, hey, just exactly where would one find good rear hatch glass for a Montreal?
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