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View Full Version : Buffed scratches out of an E46 M3 windshield



Average_Jerk
11-24-2012, 10:40 AM
I had a customer come by the house this morning for me to do a little cosmetic work on his M3. The wind deflector had gotten off alignment on the wiper arm and dragged across a section of the windshield leaving tons of scratches taking up about a 5"x12" area along the a-pillar. You can see in the pics, I have the damaged area marked off with tabs of painters tape so I know what area to focus in. Since the scratches werent too deep, I started with 500grit sand paper on a buffer to get the initial damage out of the windshield. After that, I went to 1000grit, then 2000grit. Then with some buffing compound/polish I hit that whole area of the windshield with a buffing pad. Took about 45mins including setup and breakdown of the drop clothes. But when it was all done, good as new. This is something that I do fairly often, so I figured Id share since scratches on windshields from wiper arms are pretty common. Only took a couple pics. Cant see too much in them, but here they are anyway


Just getting setup. Cover the car so I dont get dust and buffing compound/polish all over everything, You can see the damage area marked with tabs of painters tape

http://sphotos-a.xx.fbcdn.net/hphotos-prn1/644151_4472011251593_1532816882_n.jpg


Damaged area after being hit with 500grit to get the scratches out of the laminate.

http://sphotos-b.xx.fbcdn.net/hphotos-ash3/62255_4472010971586_1718742488_n.jpg

And a final view from the inside after I was done. Scratches are all gone. (I didnt get a before pic because Im an idiot)

http://sphotos-b.xx.fbcdn.net/hphotos-snc6/252368_4472011171591_15311877_n.jpg

Dudermagee
11-24-2012, 11:51 AM
looks good man

Khalil
11-24-2012, 12:48 PM
Nice job dude!

1badg35
11-24-2012, 03:32 PM
how exactly was this achieved? I have a scratch on my rear hatch glass that I would love to have removed..

Average_Jerk
11-24-2012, 03:35 PM
how exactly was this achieved? I have a scratch on my rear hatch glass that I would love to have removed..
How deep is the scratch on your glass? these ones were clearly visible and you could feel the damage by rubbing your finger over it, but it wasnt deep like cut with a razor blade?

1badg35
11-24-2012, 03:57 PM
same. it is physically visible from the inside and outside, but doesnt have much depth to it. you definitely can feel it though with your fingernail. Im not so much worried about visibility as I am moreso just annoyed. the paint is almost 24 years old and doesnt have a scratch on it, but the glass however has this scratch that makes me nuts

Average_Jerk
11-24-2012, 04:05 PM
same. it is physically visible from the inside and outside, but doesnt have much depth to it. you definitely can feel it though with your fingernail. Im not so much worried about visibility as I am moreso just annoyed. the paint is almost 24 years old and doesnt have a scratch on it, but the glass however has this scratch that makes me nuts
haha. its really easy. get some kind of non-orbital buffer or ever die-grinder or something would work. since its so light, you can start with 500grit like I did. you want to go over the damaged area until the scratches are gone. as the windshield starts to haze, you'll still be able to see any remaining scratches. when its all gone, step up to 1000grit. But use it over a slightly larger area than you did with the 500. Step to 2000grit and same deal about enlarging the area. BE VERY CAREFUL ABOUT HEAT AND PRESSURE ON THE GLASS. if you go over an area too hard, with too much spinning speed or too often you can heat up the glass and cause a distortion. Thats because the glass got too hot. after that, use a polish and buffing pad and buff the area, then wipe it off. wait for the glass to cool down in between steps. repeat until there is no more hazing on the glass. same idea applies to spreading the area out. On this M, when I buffed, I did the whole area of glass that was taped off so it would blend into the rest of it. in this example, I think I buffed that section 4 or 5 times before all the haze was gone.

1badg35
11-24-2012, 04:31 PM
cool thank you for the help. I detail cars all the time, but am always afraid to mess with the glass which is why it has been left untouched. I will however give this a shot.

any particular rotational speeds to start out on for the initial steps? obviously with heat being the issue, i will try to find the right rpm thats not too fast to heat the glass up too much.
I think ill try it tomorrow. will post up my findings.

thanks for the tips. came out great in your work above!

Average_Jerk
11-24-2012, 04:36 PM
cool thank you for the help. I detail cars all the time, but am always afraid to mess with the glass which is why it has been left untouched. I will however give this a shot.

any particular rotational speeds to start out on for the initial steps? obviously with heat being the issue, i will try to find the right rpm thats not too fast to heat the glass up too much.
I think ill try it tomorrow. will post up my findings.

thanks for the tips. came out great in your work above!
the buffer that I use is more like a hammer drill, where its got a handle and different trigger pressure changes the RPM. so I dont have an ideal number for you. I buff and use the higher grit at a higher RPM than with the 500 or sometimes 360 is its deep enough. also, when I sand, I sand dry. then when I buff I spray the polish on, buff, spray with water, buff, wipe off. Thats the process I use

mrkrinkle
12-04-2012, 10:56 PM
Would this same process be used to get pitting out? I would assume it would, but it would be really labor intensive.

My only concern would be uneven materiel being removed so after finishing, the windshield would distort the view looking through it.

Average_Jerk
12-05-2012, 11:19 AM
Would this same process be used to get pitting out? I would assume it would, but it would be really labor intensive.

My only concern would be uneven materiel being removed so after finishing, the windshield would distort the view looking through it.
there is only distortion if you apply too much pressure or go over an area too many times. You need to keep an eye on the windshields temperature. the amount that is sanded off is so minor that you would never notice "uneven material".

and pits are handled totally differently.

mrkrinkle
12-05-2012, 06:26 PM
How would you go about sanding pits out?

Average_Jerk
12-05-2012, 08:37 PM
i wouldnt sand them out. I have a couple chemicals I use that blend them back into the windshield

Rob&co
12-06-2012, 10:29 PM
Holly Shit Wonder Dave!

metalmonkey47
12-07-2012, 12:30 AM
Outstanding! I think this is something I want to try on my 30 year old Datsun glass. My wipers are SHIT in the rain and it's impossible to see at night from all the years worth of scratches.

TinaTwilight
10-11-2013, 05:18 AM
I have also made the mistake of trying to get the dirt off my car by wiping my sleeve across it. My friend quickly pointed out that I should not do that because the dirt can make the scratches worse.

superlowdub
10-13-2013, 09:39 PM
good luck man