I pulled a couple of OEM fog lights from the PNP + the needed relays, switch, jumper, etc. to install in the sled. Both lenses were badly pitted. I wanted to polish them clear before using a protective film. Problem is the 'net is full of polycarb HDLT lens polishing, rather than GLASS polishing.
I found this helpful link
of a BMW owner who wanted to restore his own.
As I owned a nice Bosch RO sander/polisher + a wide assortment of sanding disks I use for woodworking, I started with it. Very mediocre results. Why? The pad isn't driven
; it just shakes
around. If you press hard enough, the pad will stop.
I detailed the entire experience over on MVS [here]
, so I won't repeat all the mistakes.
I wound up using my dress press set to a spindle speed of 2650 RPM, a 3M medium H&L backing plate and the same 6" sanding pads mentioned above. As tempered
glass is much harder
than polycarbonate, you need more pressure & higher surface speed
. You also need to sand dry
. The key ingredient to achieving water-clear glass is cerium oxide
. I managed to obtain some from a local astronomy source and it just so happened to be the right grit for polishing
rather than curve generating
. Fortunately you can easily order red cerium oxide from the 'net. The product I used is about 13 microns, which is close to a FEPA P grit of 1500.
Here's the photos:
This is what both lenses looked like before. While the glass surface was clear, it was heavily pitted.
My previous best efforts resulted in this:
While much better, it's still not good enough. The light bulb reflection is smeared, the glass surface is now hazy and scratches remain.
My final efforts look like this:
The sky had clouded over by the time I finished, thus I had to use the shop light. It's difficult to take a photo of a polished, shiny surface however the lenses are now water-clear.
I'll cover this with a protective film, let it cure, then install them (finally).