While replacing some bulbs in a 12 inch flush mount ceiling fixture I did not remount the globe correctly and now would rather find replacement glass than replacing the whole thing. It has a really stupid mounting system where two flat pieces of metal along the diameter of the fixture is supposed to mate with slots in the glass. Then you just twist. I do not know what this is called, but figure it must be at least slightly standard. How do I go about finding replacement glass?
That’s called a “bayonet” mount.
You’ll need to measure the diameter of the base, and try to find a replacement globe, but be aware that they are not standard.
Take a photo with a ruler as a guide, and go to Home Depot or Lowe’s and see if they have anything that will work.
Also look around on/inside the fixture and see if you can find the manufacturer – that will help in finding replacements. (Unfortunately, the manufacturers sticker is sometimes on the back side, which is now buried into your ceiling.)