Wall Mirror

A while back, I came up with a couple design concepts of a wall mirror frame for the art niche above our fireplace. Originally I envisioned that the mirror would be made out of Koa.  After sleeping on the idea for the first concept, I considered it to be too symmetrical and boring.  So I revisited it and came up with a seemingly random, radial pattern of various thicknesses (1/2″, 3/4″, and 1″). The concept was to not have two slivers adjacent to each other the same thickness or length.  I slowly start acquiring various pieces of Koa from sellers on eBay. However, I quickly realized that it would take quite a long time to get my hands on enough wood and, in the end, would be very expensive with little to no margin for error.

In an attempt to better unify our family room decor, I recently painted all of our side tables white.  After that, I then realized the mirror should also be white, as well. So I shifted away from using Koa and decided to make the mirror frame out of paint-grade poplar.

To begin the build process, I made a trip to Mason’s Mill and Lumber Co. to pick up some rough 4/4 and 6/4 poplar that I would plane down to the proper 3/4″ and 1″ thicknesses. I found it less wasteful in time and money to obtain the 1/2″ stock from Lowes.

Per the design of the mirror frame I needed 72 individual pieces of wood in the following quantities:

  • 2-1/8″ wide x 1′-0″ long – 6x at 1/2″ thick, 6x at 3/4″ thick, and 6x at 1″ thick
  • 2-1/8″ wide x 1′-1″ long – 6x at 1/2″ thick, 6x at 3/4″ thick, and 6x at 1″ thick
  • 2-1/8″ wide x 1′-2″ long – 6x at 1/2″ thick, 6x at 3/4″ thick, and 6x at 1″ thick
  • 2-1/8″ wide x 1′-3″ long – 6x at 1/2″ thick, 6x at 3/4″ thick, and 6x at 1″ thick

I started out by surface planing the rough lumber down to the required thicknesses and in the process accumulated quite a bit of sawdust. With that done, I ripped the boards to width and then cut them into the various lengths. After they were cut, I marked a line 6″ from what would be the inner end on the back of all the pieces to serve as a registry line for cutting my biscuit slots later after the angled sides were cut. Also, in order to help myself keep track of which side had been cut on each piece, I marked each side.

To cut the angled sides, I created two jigs to make both the first and second side angle cuts so that each individual wood piece ended up being a sliver of 5°. After the sides were cut, I then cut the biscuit slots to help with alignment during the glue up.

With everything cut and slotted, using a color map to show where each piece went, I did a dry fit of all the pieces. Once that was done, I then numbered each piece so I could easily identify the order of the slivers during glue up.

I went into the glue-up process with a plan of attack, but that quickly melted away due to inherit limitations of my design. I had originally planned to glue each piece together and shoot a 2″ pin using my air-nailer through the side of each sliver to hold it together while the glue set. This worked well with the 3/4″ and 1″ pieces, but was problematic with the 1/2″ thick wood because the nails had a tendency to “wander” out of the face of the thinner stock. So I proceeded to just glue up small sections using the pin nail technique until I ran into a problematic 1/2″ thick piece.

Once those sections were glued up, I then used a strap clamp to apply pressure while the glue setup for the multiple sections. Eventually, I was able to create about 4 larger sections that I could then glue together and drive screws through the backside of the sections to use as clamping points. I eventually got the entire piece glued up.

After being fully set, I realized that the thin 1/2″ stock coupled with the fact that my clamping methods didn’t provide adequate pressure over the entire length of the joint resulted in a somewhat weak completed piece that could easily separate. To combat this, I decided to glue a single piece of 1/8″ Baltic Birch Plywood across the back to help tie the pieces together. I wanted to use a thin plywood to help keep the final profile against the wall shallow. I cut the plywood in an octagon, spread on a layer of wood glue and pin nailed it at various points around the back of the mirror frame. Once the glue finally set, it made the mirror frame much more stable.

After a close inspection from the boss, I was able to move on to cutting the circular opening for the mirror.

To cut the circular center, I needed a circle-cutting join for my router. Using this guide as a go-by, I made my circle jig to pair with my router.  I started cutting the circular opening from the back-side with incrementally deeper cuts until I cut all the way through the frame.

Once it was done, and I turned it over, I noticed some router tear-out on several of the thicker pieces that occurred as I was cutting the circle. Before I cut the circle, I didn’t think an original design detail was actually going to be needed, but I revisited it once I saw the tear-out. The detail was to provide a chamfer around the circular opening. So I setup the router in my circle jig with a chamfering-bit and cut the chamfer on the front side. It didn’t totally eliminate all the tear out, but it did help minimize its impact.

My plan was to have the mirror frame set flat against the wall (hence why the thin plywood backer).  So in order to not have the hangers create an unwanted gap behind the mirror, I routed recesses in the back to receive the sawtooth hangers.  However, after I cut out the circular opening, I noticed that the frame started to warp upward at the center.  I have to assume that cutting the circular hole in the plywood backing allowed this slight warping to occur.  In the end it does not appear to be that bad of a thing, and actually looks kind of cool.  But it was not what I intended and now the frame does not sit totally flat against the wall and it has made hanging the mirror more of a challenge.

With everything cut, I did final prep sanding and then sprayed the primer coat.  Once the primer coat finished drying, I did some sanding to correct blemishes and used some latex caulk at the seams where a gap existed due to the inadequate pressure during glue-up.

With that all done, I brushed on a coat of Sherwin Williams Waterbased Enamel in the same color to match the end tables.  The mirror glass insert was purchased from Binswanger Glass and I installed it in the frame using silicone sealant. With the mirror installed, it was time to hang it above the fireplace.

Lessons Learned
IF I were to make this frame again, I would consider the following things due to the lessons learned on this build:

  • Consider using 3/4″, 1″, and 1-1/4″ thick stock in order to utilize pin nailing during glue-up.  However, would need to study to see if the thicker pieces make the frame too bulky.
  • Use two biscuit slots per sliver to help with alignment and hopefully help prevent future warping.
  • Use thicker plywood backing if necessary to hopefully help minimize warping.
  • Cut circular mirror opening in multiple passes with shallower depth increments to help minimize tear-out.