A few weeks ago I managed to scratch my screen quite badly. From the impressions I got from reading about Gorilla Glass, I assumed that I could get away with not having a screen cover for a little while. It turns out that this was a very bad idea. While Gorilla Glass is very tough, even if you are careful with it, there are situations where it can get scratched quite easily. I accidentally put a plastic credit card style hotel key in the same pocket with my phone. I am very anal about my screen and I check it for scratches each time I put in my pocket. After about twenty minutes of the hotel key being in my pocket with the phone, the screen went from completely flawless to very badly scratched. There was no metal on the card; it was entirely plastic. My theory is that some grit became trapped between the card and the screen. Either way, it goes to show that Gorilla glass is not impervious to damage.
Shots of the damage:
As you can see there were several deep scratches and many more scuffs. Many of them were visible when the phone was on and caused ugly lines of distorted color. I'm afraid I forgot to take pics of the phone with the screen on before I started the repairs, but you can see what I'm talking about in the later pictures. This kind of screen condition is, IMHO unacceptable. I called up Samsung and they said it would be 160$ to repair the damage. The entire AMOLED screen has to be replaced because the glass is built in. Even though the information I was able to gather about gorilla glass polishing was less than encouraging, I figured that I may as well give it a shot. Worst case, I ruined the screen. The tech support guy confirmed that the Vibrant, (and I assume all galaxy S phones) have no coating of any kind, it's just glass.
Part 1: Materials and Preparation
Looking around I learned that some people had had some success polishing their non-Gorilla Glass iPhones with an industrial glass polishing compound called cerium oxide. I called around town to several windshield repair specialists and found someone who was nice enough to give me some for free! If you don't have as good luck you'll need to buy it online, because as far as I could tell it is not carried in stores. It can be purchased from Amazon
Some of the iPhone polishing guides mentioned that high grit sandpaper is useful to polish out deeper scratches. I went up to an Auto Zone and purchased a pack of 1000, 1500, 2000 grit wet dry sandpaper as well.
Even though the phone has a seal around the screen, I figured it would be worth it to tape up the edges with electrical tape. At the very least this needs to be done to the speaker. I found that the electrical tape worked extremely well, and left no annoying residue.
Part 2: Sanding
The second step is to sand the screen's phone down. The objective of this part is to remove the top layer of glass that has the scratches in it. This part is important as the polish is not abrasive enough to eliminate any but the lightest scratches.
Guides for polishing older iPhones warn you to go very easy on this part and say that you expect to significant result in about ten seconds. This is not true with Gorilla Glass. On my first attempt I went at it very hard with 1000 grit for several hours. This proved to be entirely insufficient:
As you can see I got a little bit of a scuff going, but was unable to remove enough of the top layer of glass to get rid any of the remotely deep scratches. You can see in the second picture that most of the scratches can be seen in spite of the scuff marks. In order for this screen to turn out properly, the old scratches need to be completely obliterated by the finer scuff marks. After I polished out my first attempt, it was clear that I had made very little progress. Application of a screen protector (not pictured) only exacerbated the deep scratches, due to the fact that an air pocket was created in the groves from the scratches.
So I gave it another shot. This time I went down to 800 grit and pressed down as hard as I dared without breaking the screen. In order to avoid excessively polishing one area and getting lensing I kept moving over the entire screen. There are two things to note here. First, keep the sand paper wet. Make a puddle of water on the screen that you can use to quickly rewet your sandpaper. I tried dry sanding, but that wasn't any faster and introduced a few new scratches that required more polishing to get out. Keeping the paper wet seems to alleviate this issue. Second, Gorilla Glass with eat your sand paper for breakfast. It will lose most of it ability to affect the screen after a few seconds. I cut my sheet of sandpaper into one inch squares and switched about every ten seconds. This seemed to help things go faster.
After a looong time, the original scratches were almost gone and the screen has a nice matte finish. This took several hours. This next pic compares properly sanded surface to polished surface in the center. Notice that the original scratches are no longer visible and that the unpolished surface has a nice homogenous texture.
I stopped sanding when the deepest scratches were almost but not completely gone. The key here is to smooth them out enough so that you don't have rough edges that diffract the screen light. If you have done it right, the scratches with be so shallow and polished that there will be no air gap created under the protector, and they will disappear completely.
Because the sanding takes so long, I suggest experimenting with something a bit harder than sandpaper. 800 or 1000 grit diamond polishing compound would probably be more effective. This stuff is designed for polishing metal, so it might do the trick.
Part 3: Polishing
On to the polishing! You will need to use a drill press, drill or some kind of rotary tool or else this part will simply take too long. I used a rotary tool with a felt wheel. This part took some tweaking to get right. You want to have a bowl of water and a bowl of cerium oxide mix handy. Mix a bit of water into the cerium oxide until you have a nice thick texture with no lumps in it. Dip the rotary tool in the cerium oxide water mixture, and start it up before you pull it all the way out of the bowl or else the polish will go everywhere. Also, dab a bit of polish and water on the phone and mix it together into a very thin mix. You can pull a bit of this into your work area from time to time to keep your polishing pad from drying out. This takes some finesse, but you will have plenty of time to perfect it. Again, you will need to press down very hard to get results. Gorilla Glass is very tough! This will generate a good amount of heat, so keep moving and touch the screen every so often to make sure you don't cook the phone's innards! Also, I recommend getting some kind of cloth bit if you can. The felt wasn't durable enough and disintegrated easily.
This will take quite a while, but if you keep at it, the scuff should start to give way to a nice shine like you see in P.9. I turned it on to make sure it still worked from time to time. Notice the pink areas where I have not begun to polish yet.
Here, I am very nearly finished with the process. There is still some polish to be done near the edge. At this point I abandoned the electrical tape except for on the speaker so I could get closer to the edge of the phone. Happily, it caused no problems!
It’s a little dirty, but the scratches are almost gone.
When I had finished, there were still some very slight "orange skin" looking areas in the glass when you held it up to the light, but it was all smooth. That is the key. The protector will eliminate this "orange skin" effect.
After application of the screen protector, (I used a REALOOK, it's fantastic. Other members have attested to this.) Few scratches were visible, and those that were could only be seen when the phone was viewed in just the right light. The photographs exaggerate them, but it really does look perfect when the screen is on, which is mission accomplished in my book!
Pics P.14 through P.17 were taken with the protector installed. Note that a lot of what you see on the screen are not scratches, but dust on top of the cover.
You can see the "haze" from the protector in P.15. It is exaggerated in the lighting. It is not at all visible when the phone is in use.
And some shots of the phone in action:
The touch screen did not suffer any damage or degradation in performance as a result of the polishing or the application of the screen protector.
All of these pics are available in high resolution at this imgur gallery:
My technique was modified from this article on removing scratches from an iPhone without Gorilla Glass.