Framing a (loose) mirror... back?

[Art Mulder]

Simple(?) question...

LOML and I just picked up a 30"x40" mirror (bare glass) from the Habitat ReStore and we want to hang it above our Family room fireplace to brighten up the place. The Brickwork goes right to the ceiling, so we'll be drilling anchors into the mortar to hang it.

We want to build a frame for it. I've never built a frame for quite that large a piece of glass. If anyone has any pointers I would welcome them.

I was planning to build the frame (like for a picture) and then mount the mirror in the frame, and then fasten securely to the wall. Is there some advantage to adding a 1/8"-1/4" plywood back to this?

When I was googling around most of what I was finding were situations where people had a mirror already mounted with J-clips on the wall, and then just built the frame to go around it. Is there some benefit to that method or is it just personal preference?

thanks in advance...
...art

[Matt Meiser]

That's bigger than I've done but I've made a few by making a frame like a face frame with pocket screw joinery, then rabbeting for the glass (be sure to plan for this when placing the screws) and then attaching a 1/4" ply or tempered hardboard back cut about 3/8 smaller than the frame so that it can't be seen. It just gets screwed right to the back which of course really strengthens the frame. I use keyhole slots to hang them. Some I've dressed up with a top cap and maybe a bottom cap. One even has a curved top rail, thought the glass is still square for simplicity. I'm sure I've posted most of them here over the years.

[Paul Symchych]

I have built one -not quite that large though. The frame was nominal 1" x ~3 1/4" cherry with M&T joints at the corners. I cut a rabbet around 3/8" wide as I recall for the glass -maybe a bit wider. Depth was so that the mirror back didn't come all the way to the frame back. The glass dropped in but not overly snugly.

Then I took it to a glass and mirror shop to let them fasten the mirror. They did it better than I could and I don't think they even charged me. I suppose you could also secure the glass with battens screwed but perhaps not glued into the frame back.

You might check with the mirror shop first to see if they want some sort of shock absorber between glass and wood [mine didn't] and what kind of clearance they need for the pins holding the glass in -if they use the pins that are driven in parallel to the back side of the glass.

[Troy Turner]

Art -

Just finished up a bathroom mirror I had cut down to 31"x31". Built the frame out of 1x4 and mitered the corners. Secured them up with wood glue and a pocket hole on either side vs. two on one side. Put a rabbet around to drop the mirror in just a bit below the edge and secured the mirror with framing tabs. The mirror was right at 1/4" thick.

One I did years ago before I had the framing tab gun and pocket jig was pretty much the same setup, but:
I just secured the miters together with a small metal strap over each miter, put a 1/4" back on it (recessed) and then just put a 1/4" strip of wood across the corners to hold it in.

So far, they're both holding up nicely. On the older one, I put a couple of hanging straps on the sides and ran some framing wire to hang it up.

[Jim Finn]

I made a frame for a mirror that measures 36" x 48" and took it to a glass shop and they installed a mirror in it using silicone caulk. It has been hanging on the wall now for over 20 years and looks as good as new. I drilled two holes through the frame and screwed it directly to the wall and put some of those button plugs to cover the screws.

[Art Mulder]

I just noticed this thread again... Sorry, I should have posted a follow-up months ago.

I decided to go with adding the plywood back. In part, I just had some 1/8" ply laying around so it was no extra expense. And I just liked the added racking strength.
243467

Further details/photos on my web page (http://wordsnwood.com/2012/mirror/), if you want.