Hello. I need some help with chossing the right type of laser. I need to remove silver from behind the mirror so that mirror is transparent. I need to do that so i can install touch sensor on the mirror. Can someone help me with what type of laser i need. Thanks in advance.
I’ve had luck in removing the silvering from a mirror back without etching the glass with a diode laser, but for a touch sensor there may be an easier way.
What is the shape/size of the transparent area you need? Often for circular areas I’ve used a flat tipped dowel in a drill press. The dowel tip is coated with abrasive paste (rubbing compound) to scour away the backing with light pressure then a switch to finer compounds to polish it up.
You can also place a drop of paint stripper or weak acid to dissolve the backing, but the edges are less defined,
Thank you for your reply. Can you tell me, what power youre laser has? I know there are other ways of removing silver from mirror, but i really want to do it with laser. I attached picture so you can see what i am talking about. Please ignore the ad on picture, i couldnt find better picture.
My laser is 10 watts (actual), but my run was at a much lower power setting.
I should explain further.
It would be near impossible to burn away the mirror backing without etching the glass. To get the image into the mirror with the glass staying window-clear, I basically burned a mask.
For this test sample, on a scrap of mirror (standard home center mirror tile), I applied some common contact vinyl shelf liner with a peel away backing that exposes an adhesive side.
The mirror with the masking film was placed under the laser with the power setting set such that the vinyl was mostly burned away.
The masking protects the area of mirror backing that I don’t want to remove.
You can see the backing (black area) exposed.
With some muriatic acid (pool/cement cleaner from the hardware store), I dripped the solution onto the burned areas, enough to cover the area but not start running all over the place.
As it began removing the remains of the vinyl adhesive and the mirror backing (aluminum I think) I would use a foam brush to gently sweep away the loose material. Occasionally I’d use a paper towel (wear gloves) to sop up the liquid then rinse the mirror off in the sink to check the progress. If the removal had not yet completed (looking for crisp edges), I’d apply more acid and work it some more.
The masking prevents the acid from getting to the mirror backing.
Here is a photo of the results with the outer area of the backing peeled off.
The tiny areas of masking take some more care with the tip of an Exacto knife to prevent scratching.
(Front)
Note that since this image has interior details, I applied the vinyl to the mirror before burning with the laser.
If you job is a simple “hole” in the mirror, you could do it easily by placing the vinyl shelf liner directly under the laser and cut the opening out. Peel off the backing and stick this to the mirror, etch, and be done! I used an ink roller gently on the vinyl to make sure it had a good, smooth application with the mirror and there was a good seal around the etching area.
Nice thing about this second method is you don’t need to be as careful with the laser power setting as you are just trying to cut the vinyl cleanly.
Note that vinyl will produce some nasty fumes which you really don’t want to breathe!
And will corrode the components of the laser itself. Not a good idea to mess with cutting regular vinyl. There are ‘Laser safe’ versions worth looking into as an alternative material. 
Be safe out there!
Thank you for youre experience and explanation. I am beginner. and i have no experience in lasers. I am in glass business and i would like to expand my business with making mirrors with led lights, clock, touch buttons, etc. To be able to do that, i need to remove reflective part of a mirror so its transparent, aka normal glass. I have a link to youtube shorts so you can see what i am talking about. bathroom mirror removing coating by laser - YouTube And i added a picture why glass cant be frosted.
