I clicked on all the Pinterest sites that offered tutorials about this, but none gave enough information. I corralled my husband into helping me, and we forged our way through, hitting some snags, but solving the issues. Here's our detailed pictorial, just in case you like this idea too.
1. MEASURE all sides of your mirror. Then, choose the wood/moulding you want to use as your frame. We spent an hour at Home Depot considering the options - wide vs. narrow, mitered corners vs straight edges with corner pieces (our final choice.)
2. PURCHASE the wood you need. At Home Depot, a saw is available to cut approximately what you need, so you aren't paying for extra length. At home, with a miter box, we finalized the cut edges of the four strips of moulding that would line the sides of the mirror.
3. MAKE NOTCHES. If you have mirror clips (we have the flat metal ones), you will need to notch out a chunk of wood on the back of your moulding to accommodate that feature. (If your mirror is glued directly to the wall, you can skip this step.)
Hold the moulding perpendicular to the mirror clip exactly where it will go. Draw the area that will need to be removed, making it a little bigger than the clip, so there is some fudge room later.
If you have a router, notch out the drawn area. If you do not (we don't), it's still easy to create the notch. Simply saw several small notches close together within the blocked off space.
Once the moulding is cut, scrape out the notched pieces with a chisel or screwdriver. They pop right out.
Your finished notch will look like this from the bottom.
This creates a space for the mirror clip. We needed to create four notches, two in the top piece and two in the bottom piece.
4. PAINT all of your wood pieces. I used a white latex enamel for easy long-term cleaning. Be sure to paint the back edges of all your wood pieces, as these will show in the reflection of the mirror.
5. DRY-MOUNT. Once the pieces are properly cut and painted, dry-mount the frame, meaning hold everything in place to check the fit. We put double-sided tape on the back of our corner pieces to temporarily hold them while we placed the side boards. You can see the faint outline of the tape here.
6. ATTACH your pieces to the mirror. This is the adhesive we used.
In most of the tutorials I watched from Pinterest, people used Liquid Nails. We started with that, but it did not grab the mirror within a minute. The first piece we applied with Liquid Nails fell off. Maybe it was our technique, or we didn't apply enough...it just didn't work for us. It might for you.
Power Grab held beautifully. We did have one issue, which I'll get to in a minute.
We glued the bottom strip of moulding first, centering it and making sure it was level (use a level.) With each piece added, we quickly checked the rest of them, assuring the fit was maintained.
When all the pieces were attached, we noticed the top right moulding bowed out a bit and would not lay flat. We clamped this piece tight. Because our mirror is not glued to the wall (but held with clips) there was a small space between the mirror and wall to allow for a clamp. I decided our mirror is probably bowed in this area and needed some help holding the wood. We taped the top pieces in place for added security.
We let everything dry overnight.
7. CAULK the cracks. No matter how straight your cut edges are, some cracks will be visible. Use a thin caulk bead. You can always add more, but you don't want a gloppy look. These three pics show a pre-caulked crack on the left, the caulk bead, and the finished look.
I used a damp index finger to smooth out the line, wiping the excess caulk on a paper towel.
8. CLEAN UP. Once the caulk is dry, scrape off any glue residue from the mirror with a straight-edge razor. We let one strip of wood slide while attaching it, so we had some goop to remove. If you're more careful than we were, you won't have this issue. I cleaned off the last smears and fingerprints with Goof-off.
The twenty-two year old mirrors that formerly had borders like this...
...now look like this.
We're so happy with the results, we're going to update the other mirrors in the house. This is an easy makeover and relatively inexpensive. I used paint and caulk we already had, which helped.
If you frame a mirror and discover other helpful tips, let me know, and I'll include them here (with recognition, of course.)
A great weekend project. Happy framing!