DIY Octogonal Mirror {Contributor Column}

The following was written by Colleen of Two Delighted, contributor for Brooklyn Limestone

Hello friends! My name is Colleen and my sister Megan and I have a blog called Two Delighted, which we started in order to document all of the DIY, entertaining, and home decor shenanigans that we get ourselves into pretty regularly. We are thrilled to be guest contributors for Brooklyn Limestone, which has been one of our favorite blogs for forever.

Today’s DIY is a bit of a doozy, so I’m going to get right down to it. I’ve loved this mirror from Ballard Designs for a while, and have almost purchased it on several occasions, but I could never justify the cost. Attractive mirrors in general are just crazy expensive. I decided to see if I could make a version of it myself to save some cash and I feel I was actually quite successful, even if things did get dicey a couple of times along the way.


  • an old mirror (rectangular or octagonal)
  • moulding from the hardware store
  • a saw (a miter saw if you can get your hands on one)
  • one of those long cheapy mirrors that we all took to college with us like so 
  • mirror cutter (tip: it is easier to cut away from you than toward you)
  • wood glue (I used Monkey Wood Glue)
  • Mirror mastic 

  1. You want to start out with a clean mirror, free of any frames or heavy backing. I found an octagonal one from Restore for cheap and took off the frame. My warning to you is that using an octagonal shape makes things about 50 times more complicated, so I would maybe start with a rectangle shape. Go to Home Depot or Lowes and find moulding in the wood section with a lip on it to go over the mirror. Estimate how much you will need by figuring out the circumference of the mirror and then multiplying by 3 since there will be two layers of frame and you will inevitably mess up several pieces. Measure each side of the outside edge of the mirror, and mark the inside of the moulding with the length. You will need to cut each piece with angles on each side. For an octagonal mirror, use 22.5 degree cuts and for a rectangular mirror, use 45 degree cuts. After you’ve cut all the pieces, lay them over the mirror to make sure that they fit. We had to make a couple of adjustments by cutting pieces a little shorter. 1b
  2. Next is cutting the strips of mirror for around the edge of the moulding. Cutting a mirror is pretty daunting, but it actually turned out to be much simpler than we thought it would be. Have someone with a steady hand (a lovely and helpful husband, perhaps) do this part. Lay a towel underneath the long mirror to have something to catch any fallen glass. I used a long piece of moulding as a straight edge, and drew three straight lines with a washable marker equidistant across the length of the mirror to make four equal strips of mirror. To start cutting, dip the glass cutter in a little bit of oil (vegetable will work fine although there are fancy glass oils) and wheel the glass cutter over one of the marked lines with firm pressure. You will hear a kind of squealing noise if you are doing it right. Once you have gone over the entire line, place the mirror over a broom or long dowel, with the mark lined up with the broom. Then press down gently on both sides of the mirror to cut. Once you have the strips of mirror, you can start cutting them into shapes to line up with the existing pieces of moulding. For each piece of moulding, use the outer edge to mark the inner edge of the corresponding piece of mirror. To cut 22.5 degree or 45 degree angles depending on your shape, place a straight edge along the angle of the moulding and over top of the mirror to help draw the line. Look at the picture collage if you have no clue what I’m talking about because I just said a lot of things and it is kind of confusing. 2b
  3. Now you have the inside moulding and the pieces of mirror, so you just need the outside pieces of moulding. You will want the lip of the moulding to go a little bit over the mirror to cover up any scraggly edges, so figure out how you want it to line up and then mark the inside edges for the new pieces of moulding. Then cut the angles again, just like you did in the first step. Lay down all the pieces to make sure they will fit together. Again, we had to re-do a couple of cuts so don’t feel bad if you cut a wobbly piece and need to re-cut. I don’t have a picture of this part, but you will probably want to stain or paint your wood pieces. I used a combination of grey stain and white wash stain, but you can use whatever you want. 3
  4. Measure the outside of the mirror both horizontally and vertically and go back to Home Depot to grab the cheapest particle board you can find and get the nice people to cut it for you. If you decided to do an octagonal mirror, you will need to lay all the pieces over the board and mark around the edges so you can cut off the angles. Also mark around the center mirror so you glue it back in the right place. Spread a good amount of the mirror mastic within the marked area and press down the mirror. To make things a little more sturdy, I screwed in tiny screws around the edge, being careful to not put too much pressure on the mirror.4
  5. Use wood glue to glue down the moulding one piece at a time, holding it firm until you feel like it has been properly set. 5
  6. After the first set of moulding has been glued down, use mirror mastic to place the pieces of mirror around the edge, one at a time. Use very fancy clamping tools like old canned goods to hold the pieces of mirror in place. Once the mirror has set, use wood glue to place the second set of moulding. Go get yourself a cookie and take a nap because you will probably need one.
But isn’t it lovely?


  1. What a great project. I love how it turned out.

  2. Love it! Fabulous job Colleen!!

  3. This really is an awesome project and it came out so perfect-- I would have never known you made it!


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