I have a large mirror that's glued to the wall so I can't remove it. It already has a 1 gang outlet in it but I'd like to expand it to a 2 gang box. How would I expand the hole on a vertical mirror that also has drywall behind it?

  • 6
    All I can say is good luck and be prepared to buy another mirror.
    – Solar Mike
    Commented Apr 18, 2020 at 6:21
  • Before you go all cut crazy, can you tell us what you want the two gangs for? Commented Apr 18, 2020 at 16:38
  • lol, that's what I'm afraid of @SolarMike
    – chizou
    Commented Apr 18, 2020 at 20:46
  • @AloysiusDefenestrate the 2 outlets that I have today aren't enough.
    – chizou
    Commented Apr 18, 2020 at 20:47

2 Answers 2


Get a 100mm angle grinder and stick a smooth 100mm diamond wheel on it, you should be able to plunge cut the slots needed to remove the extra piece of glass

wear a dust mask, ear and eye protection, go slowly brace against the wall pr mirrior with your elbows and use both hands to steady grinder keep the blade straight when cutting.

wipe down all surfaces with a damp rag when done.

  • 3
    I would try and practice on a piece of mirror beforehand. Maybe find one in a thrift shop. Of course the two mirrors could behave differently though Commented Apr 18, 2020 at 11:24
  • And I suspect that a smaller tool like a rotatry to (often called a Dremel) would be better for the job. It would be easier to control exactly where to cut and where to end a cut. And I imagine it is less likely to shater the entire mirror with vibrations. Commented Apr 18, 2020 at 11:28
  • 3
    yeah, but much much slower. vibrations won't shatter the mirror. if the cutting wheel jams that could, but with care than can be avoided.
    – Jasen
    Commented Apr 18, 2020 at 11:47
  • 1
    I suggest setting up a vacuum with the hose very near your cut to capture the dust, preferable one with a HEPA filter. Also wear protective clothing in the case that the mirror breaks as sharp shards many fall down and hit you
    – Ack
    Commented Apr 18, 2020 at 16:41
  • 2
    Water will cool the blade and suppress dust. but you don't want damp inside the wall. so it's not an option. Without water the blade wears out faster but it will still last plenty long enough to cut the three slots needed for this task.
    – Jasen
    Commented Apr 18, 2020 at 22:53

Cutting or drilling a hole in a mirror is something that takes either very specialized tools that are not easily available, or an EXTREME amount of luck. If you have a high speed rotary tool, like a Dremel, and a diamond encrusted bit made for grinding glass, you might get lucky. Do NOT breath the dust that comes off of that.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.