Any tips for sanding glass?

[Kaban]

Does anyone have any pointers for sanding glass foglights?

Just trying to sand out some medium scratches in them and polish them back to a high gloss. They are off a newer Mercedes and it's an extremely hard glass to work with. It feels like it's bulletproof.

[natt2000]

id start at 60 or 80 grit and work on up depending on the severity of the scratch.

[Kaban]

Thanks for the tip. I tried my 3" random orbital on full speed and it doesn't even put a scratch on it. I've been using the rotary with a small backing plate and small sanding disks at around 1200-1500 rpm to cut through the defects. The orbital sander was literally not doing jack to the glass besides putting in pigtails.

[Kaban]

Guess nobody knows.... I tried teh LC glass cutting pads and they are not able to take out even the smallest scratches out when used with ceriglass and a rotary buffer at a high speed. Pretty dissapointed in them since they are termed "cutting" pads for glass and they don't do anything.

[Rsurfer]

Have you tried full strength cerium oxide?

[swanicyouth]

Look on you tube for guys doing it with commercial glass. I saw some videos where guys did what looked like wet sanding. The problem is, most of them are selling their special equipment to do so.

The thing is, if the CeriGlass isn't touching the scratches now, it may not clean up the sanding marks. I'm guessing its a special glass not to shatter for fog lights. Unfortunately, you may just have to replace them.

[Kaban]

Have you tried full strength cerium oxide?

Not yet, but I have been thinking about it. Will it have considerably better cutting power than the Ceriglass? By considerably I mean Menzerna SF4000 vs. PG400. To me the Ceriglass is an extremely mild polish at best, at least in this case. It is removing the haze but it's not touching any of the scratches (which are similar to RIDS in paint)...not nearly deep enough to catch with your fingernail, but you can see them all as soon as you look at the glass under a light.


Look on you tube for guys doing it with commercial glass. I saw some videos where guys did what looked like wet sanding. The problem is, most of them are selling their special equipment to do so.

The thing is, if the CeriGlass isn't touching the scratches now, it may not clean up the sanding marks. I'm guessing its a special glass not to shatter for fog lights. Unfortunately, you may just have to replace them.

I'm definitely thinking it's a special glass also. I guess I'll try the cerium oxide and if that fails I'll just cut my losses and replace them.

[Kaban]

I got some cerium oxide on the way to try out. Does anyone have tips from experience on the best way to mix it? Do you just mix with water 1:1?

[rwright]

If the LC glass pad is not working then I would look at the glass pads that CarPro offers.

[Rsurfer]

I got some cerium oxide on the way to try out. Does anyone have tips from experience on the best way to mix it? Do you just mix with water 1:1?

Just mix it into a paste. You must keep it wet, so it will get messy .

[Kaban]

Just an update...


I did manage to correct about 90% of the glass on the fogs with the Cerium Oxide and LC glass cutting pads. I could have gotten a full correction out of them but I honestly thought it was good enough and nobody is going to look at them under a microscope.

What did the trick is using a VERY slow arm speed, Very high RPM ( I was running the PE14 between 1800-2000 after spreading the cerium oxide). Also, I cut down the pad to 3" and used it with a gloss-it 3" foam backing plate which is the softest one I have seen. The backing plate made a huge difference in providing a smooth polishing process.

I waited about 2-4 minutes between each pass to let the glass cool down and did IPA wipedowns and inspection after every pass. It took about a dozen passes or so to remove the sandmarks (320 sandpaper). I tried higher grit of paper to simplify the polishing process but with this particular glass, the higher grade of paper was just getting clogged up right away and not doing anything.

Alot of work, I feel humbled. I feel like I learned a hell of alot also. Much more involved and more time consuming than paint correction or polishing regular plastic lenses. I've done probably over a hundred plastic lenses (full corrections with either spar urethane and or professional clearcoat), but this takes the cake in difficulty level.