Drilling holes into a mirror is a tricky business, but it can be rewarding. The key is to work slowly and show lots of patience. You also cannot drill a mirror with a regular drill bit. You must find one made to drill glass. The thickness of the glass can also affect your results. Thicker glass tends to be easier to drill, for example, as it is not as likely to crack the as thin glass. Use the right tools and follow these steps to get the job done.
Before you begin drilling, place the mirror on the plywood with the backside face up. Make sure the plywood and mirror are at a comfortable height for you to work with. Then, make marks where you want your holes to be. Do not plan holes too close to the edge, or you will risk damaging the mirror.
Tape the transparent plastic onto the mirror. If you do not have access to transparent plastic, tape the area you wish to drill instead and use the marker to show the exact center of the holes you wish to create. Be sure you are wearing your face mask before you begin drilling.
Create First Holes in Plastic
Use a regular drill bit and bore through the plastic directly above the marks on the back of the mirror. Drill slowly and do not drill any further than the plastic. These holes will guide you as you begin to drill into the glass. Skip this step if you do not have plastic.
Drill the Glass
Exchange the regular drill bit for the diamond drill bit. Using the regular drill bit on the glass will only dull it, and you will also be more likely to damage the glass. Next, place the drill above the glass, inside the holes through the plastic. The drill should be held at a 90-degree angle with the surface. Then, slowly begin drilling into the glass at a constant speed and with light pressure.
As you progress, you will see fine glass dust coming from your drill. You should already be wearing a face mask, but do not breath this in; it is very harmful when it comes in contact with your lungs. Use the water to keep the area moist as well. This will help prevent the bit from overheating and will make it easier to bore through. As you drill, lift the bit from the hole to allow the water access.
Once you are through the mirror, turn it over. Carefully and slowly drill into the hole from the front side. Be careful as chips of glass may begin to fly around. Again, keep the area moist.
Once you have completed drilling the holes, use a wet rag to wipe away any excess dust. Then, remove the tape and plastic cover, and clean any marks left by the tape. The mirror is now ready to hang on your wall.