I recently replaced the bumper on my 1998 C70, but I wasn't happy with the freshly painted bumper with the 14 year old fog lights. They had pitting from many years of driving and some over spray from the stealership that sold me the car when they touched up the old bumper for sale.
solutions...
buy new (or newish) fog lights
replace with aftermarket
try to fix what is there
I decided to go with the latter because it was the least costly, leaving money for other projects. In all I spent around $20
I started doing some research on the internet and found a few decent how-to's, including something from a BMW forum and a glass maker. Feeling confident, I began.
Before I go on, I must say that if you decide to do this it is at your own risk. There is a chance you could crack the glass (especially if you decide to use power tools).
I gathered the necessary materials shown below
- sandpaper (60, 100, 220, 320, 400, 600 grits) You don't need to have these specific grits, but make sure to go from course to extra fine. It would be helpful if the finer ones are on waterproof paper.
- cerium oxide powder
- hand sander (I ended up ditching the one in the picture and just used a block of wood)
- microfiber towels
- applicator pad
- mask (I can't stress this enough - you don't want to breath in glass particles)
- protective eye wear is also suggested. I wore them, but didn't include them in the pictures
Starting with the coarsest sandpaper I began dry sanding the glass in a circular motion. I did this by hand, so I was not worried about heating the glass to the point of breaking or wearing the glass too thin. If you use a orbital sander or electric drill, you will want to do this in short bursts lasting less than ten seconds. Then allow the glass to cool for about 10 minutes. Wiping away the surface with a moist microfiber cloth, I sanded until I could not see any more pitting, between 10 and 15 minutes. I know it looks bad, but it gets better this is the unwiped surface after being hit with 60 grit
In the opposite rotation, I moved to the 100 grit sandpaper. I did this for about another 10 minutes. You'll notice it's getting better, but not great yet. When you wipe it, it looks pretty good. But when it dried, I got a bit discouraged. Don't worry.
Going back to the original rotation, I dry sanded using the 220 grit. I did this for about 7-10 minutes.
Now it's time to make a noticeable difference.
Going in the opposite direction, I began wet sanding using the 320 grit with the waterproof paper. I did this for about 7 minutes
In the original rotation, I wet sanded using 400 grit for about 5 minutes.
Finally, I wet sanded in the opposite rotation using the 660 grit for about 5 minutes.
At this point it looks really good, but not like new. Now I moved on to polishing using Cerium Oxide. I picked some up for a few bucks on amazon. With shipping, I think it was around $15. I got an 8oz. container, but only used about a tablespoon for both lights. So I've got plenty left over.
When mixing, make about equal parts water and powder. You'll have to add water as you apply because it clumps up with the friction.
I used an extra applicator that I use for waxing the car. A little dab on the applicator goes a long way. no need to completely saturate the pad.
I worked this in for about 10-15 minutes, stopping to add water and check progress. Finally I stopped and wiped all of the polish off.
Here is both of my fog lights side-by-side to show the before and after. Sorry it's not the best pic in the world, but you get the gist
I'm very happy with the results. Tomorrow, I'm going to my parents for dinner and work on another project (project dashboard...coming soon) I may use my father's orbital sander for the other light. If the results are better, I'll post pics.
I hope this is helpful to some of you. This wasn't the worst job in the world. I was reluctant to jump on this because I was afraid of messing up. I'm very happy that I decided to go ahead and do it. It was much easier than I anticipated.