I have a 50lb mirror I'd like to hang. It has an iron frame with two hangers welded onto the curved top edge on the back. Here's a close-up of one of them:
The hangers are about 17" apart on center, and the keyhole cutouts are 3/4" wide. The wall is standard drywall, and there happens to be a stud dead-center where I'd like to hang it.
What are the simplest and safest options here? Considerations:
I haven't checked yet but there's no guarantee that the brackets are 100% level, so the solution needs to be able to account for that.
I'd like for the mirror to hang as flush to the wall as possible, minimizing lean-out and gap.
I'm pretty conservative re: hanging weight and would strongly prefer using the stud for support, although I can be convinced otherwise. I saw this (Hillman no-stud hanger) mentioned in another answer and perhaps two of those could work if the result hangs fairly close to the wall, although point #1 could make this very challenging.
Preference is for a minimum of "construction": cutting wood, etc. This technique (spanning plywood) seems to be a good solution, and I can make it happen, but if there's something simpler that is as safe I'd be interested.
My experience with hanging anything close to this heavy is to just use a z-bar, but I don't have that option with this frame.
Since the answer has to take into consideration that the two hangers are not level, you're stuck with one solution: hang it like a picture. Go to your home store and get some stainless steel picture hanging wire rated for 50 to 100 pounds. Make a strong loop around one end and hook it into one of the hangers. Do the same to the other hanger so there's not much slack in the wire. Add two wires if it will help you sleep at night. Then screw a 1-1/4" lag screw and washer into the center of that 2x4 stud you like so much. Leave just enough space between the washer and the wall to slide the wire behind. Lift the mirror and slide it around until you hook the wire behind the washer.
Cut a piece of steel bar / tube that is thin enough to fit between the back of the glass and the front of the hangers and will reach between the two welded brackets. The bar needs to be strong enough to support the mirror at it's ends without significant bending so it might need to be wide. Drill and tap this so you can fix it to the hangers such that it can't move. Just to be clear, the bar is to sit inside the thickness of the frame of the mirror between the front of the welded hooks and the back of the glass. Attach to the mirror and find the point at which the whole assembly hangs vertically. Remove from the mirror and attach a length of suitable chain or wire to the bar so it bridges this centre point on the bar by maybe an inch either way.
Use this chain or wire on a suitable hook or bolt screwed into the stud. It gives you a little wiggle room in case you didn't get the position it hangs vertically quite right.
If the concern of the manufacturer is that wire between the two welded hangers will distort the frame by pulling the sides together, this stops it happening.