Giant 8 foot mirror

At the beginning of 2021, I completed the build of a large mirror frame. The blog post about that build can be seen here (https://awoodworkinprogress.blogspot.com/2021/01/the-mirror.html). Following that work, my wife and I had the big idea that I would be able to build a frame for any mirror that needed one, and even cut large glass mirrors to make smaller ones. It was a grand idea that resulted in me receiving a massive 8ft mirror that probably belonged in a commercial gym, or even a bathroom for a movie theatre. I don't recall what it could have been used for, but I accepted it as a free item from a local Facebook group. It was so large that my wife and I stored it in our living room, against the wall...behind a cabinet. It was simply too large to store it anywhere else, and I was busy working on other projects, so it sat there for 2 years.

Finally, in January of 2023, I decided to give the mirror away on the same Facebook 'Buy Nothing' group. Several people accepted the offer of the mirror without reading the details on the post (specifically the dimensions). They actually showed up to take an 8ft glass mirror with a small hatchback or sedan! While this failed-giveaway was happening, I was doing work for the same client I made the barbell rack for (https://awoodworkinprogress.blogspot.com/2022/04/the-wall-mounted-barbell-rack.html). They have a large space for their home gym, and had a massive empty wall. I offered to give them the mirror for free, if they would allow me to build an appropriate frame for it. They accepted, and that's where this project began.

Giant 8ft x 3ft mirror, with rounded corners and no frame. Very heavy!

There are obviously many ways to frame a mirror, but many of them would be unsuitable for a mirror of this size. While some might be perfectly stable, this frame also needs to be aesthetically pleasing for a mirror of this size and shape. I decided to go with a mitered frame, and the way to hold the glass would be a dado (channel) cut into the side of the boards. This would keep the wood boards flat against the wall, and that orientation would provide the most strength for the long side of the frame. 

a simple mitered frame.

For many mirror frames, a mitered joint would be sufficient in appearance and strength. For this particular job, the simple glued ends of a miter joint are not strong enough. I even doubted whether a spline added to the joint would provide enough reinforcement. To increase the strength, I decided on a half-lap miter joint. This provides the miter appearance, with the joint strength of a half-lap, which is only visible from the back. This joint provides a large gluing surface that will hold the joint well. I would also add a few screws from the back that would hold it together while the glue dries.

an example of a half-lap miter joint. The board on the top left would be flipped over and would then sit on top of the board on the right.

The client decided that they would like the wood to be finished with simple white paint, which would actually match the other equipment they have on their home gym walls (all of which I made for them). Because the wood would be hidden under paint, the wood species could be inexpensive pine. That being said, the boards needed to be structurally perfect - so rough framing boards from a big block store would not be suitable. I needed the wood to have no surface imperfections, and no warps or twists. My local specialty lumberyard (The Wood Source: https://wood-source.com/) was chosen. They have beautiful wood that is perfect for this project. After some consultation with my in-house design critic (my wife 😉), we agreed that a 2x4 would not have the right size to match the scale of the mirror. I decided to go with a 2x6 boards.

While I've been describing the mirror as being 8ft long (96"), it is actually 92". With the precise measurement, and the plan to have a dado slot for the mirror to rest in, I drew my plan and figured out what size of boards I would need to buy. The 2x6 boards are also not truly 2" x 6". They are 5.5" x 1.5". That was important because the length of the boards would need to account for the 5.5" width of the board.

Most of my projects involve a pencil sketch first, even those designed with Sketchup. Notice the height is not quite 46", and that is because of the caulking that will be in the dado channel.

The sketch doesn't show the miter, but the half-lap is clear for each corner. Due to the wide frame, the wood to buy needed to be at least 102". The wood shop sold me 10" boards that were then cut to length. I taped the cut areas with masking tape so there would be minimal tear-out from the miter saw. Once the boards were cut to length, I needed to cut the half-lap miter. There are many ways to do this. Hand saw, dado-blade on a table saw, chisel, and miter saw are all different ways of doing this. For me, with these long boards and the very large area that needed to be cut, I decided to go with my miter saw which has an adjustable-stop for this purpose.

This is one of the shorter boards, getting the miter treatment.

Marked the 45° miter line on the board with a speed square, then taped over it to keep the cut clean.

This miter cut will only be going halfway through the board.

sdfs

A close-up of how the miter saw can cut the half-lap. The depth stop can prevent the blade from cutting all the way through, so the remaining wood can overlap the other board. 

Once I did some test cuts on some scrap, I moved to the project boards. I cut the half-lap joints on all the boards. After that, I used my table saw, and cut a dado in the inner edge of the boards. This is the space where the glass mirror would be inserted. It took several adjustments to get the right dado blades that would make a channel the right thickness to fit the glass well, without requiring my to force it - I didn't want to put too much pressure on the glass during assembly. The dado channel was set precisely to 1/2" deep, as per the plans outlined above. The result was the frame cut to size, joints cut and the dados cut. Now it was time for the dry fit.

The dry fit of the the joint. This is the back side of the frame.

Here you can see the parts of the wood that will be overlapping and glued together during assembly.

A good angle to view the dado channel that the glass mirror will be inserted into.

After the half-lap joints were cut with the miter saw, I needed the overlapping surface to be perfectly smooth, so the glue surface would sit flush with the other side. If there were deviations, then the glue wouldn't connect the two surfaces well, and there could be a failure of the joint. My chisel could do this work, but I wanted to be very precise with this, so I used my router on a router sled. This gave me a perfectly smooth surface for the glued joint. 

While this surface looks good, it's not perfectly smooth.

Router bit that will slide around the surface and shave off any deviations.

The router bit got close to the inner edge, but I stopped just short, and finished the last little bit of chipping with a hand chisel. 

Now I put the frame together to see how it all looks when assembled. This will tell me if any angles were incorrect. It also gave me an opportunity to predrill and countersink the holes for the screws on all the corners. When the glue is fresh and the frame is being assembled is NOT the time to predrill the holes. This was also the time that I added a nice chamfered edge to the frame. All visible edges got a chamfer with the router.

This the frame assembled on my workbench, extending well beyond and being supported by an additional cabinet.

Predrilling and countersinking the holes.

As mentioned earlier, the depth of the dados is 1/2", but on the horizontal boards, the depth is assumed to be slightly less. This is because I am adding a small amount of caulking into the channel to cushion the glass and keep it from rattling in the frame. I bought caulking tape, which I stuffed into the dado channel before inserting the glass. As the glass pressed against the caulking tape, it squished it and the result was a snug fit for the glass in the channel. After that, the whole frame was sanded to a smooth finish. Next, I primed and painted the frame. One coat of primer and 2 coats of paint were applied.

My typical primer for most jobs.

My favourite paint for projects. Strong paint, nice finish.

Caulk cord that was used in the dado. The product worked well, but it isn't very sticky - so it would fall out of the dado when it was flipped upside down. Extra was used and stuffed into the channel to help it stay in place during assembly.

Laying the caulking cord into the dado channel prior to assembly.

I don't have any pictures of the assembly process, as I had my hands full. I had both kids holding the frame in place while my wife and I carried the glass mirror and positioned it into the dado channels. I slapped glue onto all the joint surfaces and added 3 screws to each corner from the back. The frame was built and assembled. Once it dried, I laid the frame on the table and began my final inspection.

At this time, I discovered that my calculations were slightly off. The rounded corners of the mirror were not sufficiently hidden by the dados. I needed to come up with a way of hiding them. I looked at the materials I had available - and saw the answer. I had 4 triangular blocks from the 2x6 wood that were cut off while creating the mitered half-laps. Those were the same size as the frame, and had perfect 45° angles, that fit the corners well. I simply needed to make those blocks thinner, so they would match the thickness of the frame while sitting on top of the glass.

The thick block laid into the corner. This could work!

This photo shows the small gap that is seen in the corner from the rounded glass. If the glass were square at the corners, this gap wouldn't have happened. You can also see the triangular piece that was thinned on my table saw. It had to fit the profile of the chamfered edge of the frame.

This will fit quite nicely! Just need to paint it.

The frame was already painted, which was a problem, because I wanted the triangle to be glued to the frame, not the glass. I sanded the paint off the frame, so that I could glue wood directly to wood. It is not wise to glue wood to paint, as the paint would just peel off.

All finished. The corners were glued and then they received a final coat of paint over the glued edges.

Once I was satisfied with the frame, it was time to transport this behemoth to the client. As was shown in the pencil sketch, the resulting mirror was over 46" high and 102" long. This made it too large for my van to transport in a normal fashion. I asked the client for assistance, and we drove slowly down our neighbourhood streets with the mirror hanging out the back of the van (and the client sitting on the floor of the van holding it). My home is only a few streets from the client, so it was a short drive.

We carried it down the stairs with relative ease, despite the mirror weighing over 100 pounds. The next step was to mount the mirror to the wall. This needed to be attached directly to the wall studs, many of them. This was not only to ensure the mirror wouldn't fall, but also to ensure that the strain on the mirror was distributed. Fortunately, the mirror was large enough to hit 5 studs.

I placed a long strip of painters tape on the desired wall, and marked where the studs were. I then moved that tape to the bottom front of the frame, so that I wouldn't know where to screw the frame and hit the studs. The plan was to screw the frame into the wall, with the screws recessed into the wood. I would then plug the screw holes with small wooden plugs, glued and painted. Large, 4" screws were used, as I needed to reach through the frame, the drywall and then hold enough of the stud to not move. Number 10 screws were used, which are thicker and stronger than traditional deck screws. 

I transferred the tape and predrilled the holes. Another neighbour friend came over and held the mirror against the wall, while I quickly screwed the frame to the wall, ensuring the frame was level. Once the 5 bottom screws were in place, the frame wat fairly securely - but obviously the screws at the top would be needed. I moved the tape up to the top, ensuring it lined up the the studs (using a stud finder). I secured it to the wall and let the client go for the time being. I needed to glue and paint the hole plugs. Once that was done - I packed up my stuff, and marveled at how nice the mirror looked in that large room. It fit the wall well, and will come in handy while the family does their exercises.

This project took about 2 weeks to complete. Pretty good for a second-hand mirror that I couldn't even give away!

From this angle, you can see the plugs that were installed to cover the screw holes.

This angle shows a nice view of their gym space, and the barbell rack!

Very nice room with plenty of space and to workout in front of this giant mirror.