It's hard to tell exactly how the frame is constructed, but one thing that might work is to glue the broken corners, then mount the whole thing on a piece of 1/4 plywood, the same size as the mirror. You could glue and screw from behind into the frame.

If there are chips in the frame at the edges, you might try a product call Rub and Buff to fill it. You may need to fiddle with the colors a bit.

To start off I'd never buy a frame over $100 - that's just insane.

It looks like it's made of wood - try wood glue? Super glue might do the trick as well.

The framing store people sound like they were trying to sell a frame...

This is an easy fix with glue. The hard part will be in finding something to clamp or put pressure on the corners while the wood glue ( or Elmers) dries. If it has wood plugs in the joint and they are broke you can stick some wooden toothpicks in them to tighten up the joint. Dulcibella's idea is great.

This is actually a really simple fix. All you will need is some Wood Glue and a Corner Clamp. With the wood glue make sure you dont use Gorilla glue, its good and strong but what happens is it foams up when it dries and becomes messy. Get a simple wood glue like the Elmers, its like a light brown. This glue is best for laminating wood which essentially you will be doing.

First apply ample glue to both faces to be attached and with a brush or your finger smooth it out all over the surface make sure to cover everything.

Wait about 5 min or so to become a bit tacky and then attach the two pieces together.

Apply the corner vice really tight with the frame face towards you. The glue will squeeze out so once you have clamped the whole thing use a damp towel (warm water works best and damp not wet you dont want to wash away any in the crack, this is also why you want to use Elmers cause its water soluble while it is still wet) and wipe away the excess glue on the face.

Wait no less than 24 hours. 6 hours the glue will cure but to ensure a perfectly tight bond wait 24 hours before removing the clamp.

Hope it works out for you

I work for a museum, and am restoring a historical gilded frame thats taken a beating over time. Here are some inexpensive alternatives to what I use:
First put glue on the corners. Use it sparingly, and I suggest against the gorilla glue that expands because it will make a mess. Take four L brackets (go here for a picture- http://www.k8zt.com/to_go_images/7-L_bracket.jpg ) and screws that are shorter than the thickness of the frame, and fasten one bracket on each of the corners to stabilize it. If the frame needs more support after that, depending on the size, you can think about putting a piece of wood across the back. Now check the front of the frame for any mess the glue might have left behind while it is still wet, and be sure to clean it up if it has.
If there are gaps in the corners after this, and if they are noticeable, you can fix it. Once it is dry (read the directions on your glue) take some stucco and push it into the needed areas, smoothing it out as best as you can and wiping away excess with a damp cloth. Once that sets, check to see if it might need some sanding, otherwise go ahead and fill in over the white with just a little bit of gold paint and a thinner glaze on top to blend it in (try burnt umber acrylic paint mixed with a little water).
Thats my suggestion. Good luck!

I was considering using L brackets as well but im concerned what the age of the wood is, how dry is the wood and how thin it is, it would be a real shame to crack it using a screw.

Wood glue and corner fasteners. Clamp it till dry and.... tada!!

Easy!

This happens frequently when folks hang mirrors and heavy artwork improperly:

Folks frequently run a wire in between the D-rings on the back and hang it from a single nail/hook in the wall - This is the wrong thing to do for the reason you see here, as this twists the D-Ring mountings and eventually breaks the frame apart under its own weight.

To prevent the mirror frame from coming apart like this, you must hang using two hooks, and hang directly from the D-rings on either side of the mirror frame.

That said - Without seeing the back of the frame and inside the joint, it's impossible to say how this has come apart - but my guess would be that it's going to take more than wood glue. It may require some Framer's V-Nails...

and she never used that framing shop again...

I worked for a few years in a custom frame shop, and the reason the frame shop said to get a new frame: the wood glue will never stand up to the weight of the mirror. You will be probably wasting your time.

Try the L Brackets as previously suggested. I also agree with the comment from bepsf. Dont even bother with a wire and hang directly on the wall using D Rings.

Since the frame will be holding the glass in place, it will be under a good amount of stress. So, wood glue alone won't cut it.

I'm thinking you can brace the corners with small/medium flat metal braces or corner braces. If you have a heavy duty upholstery stapler, that might work, too.

Either way, it is repairable!

Thanks for the comments, y'all! The mirror is quite heavy, so I'm apprehensive of using wood glue alone. A combination of wood glue and L brackets just might work. And thanks for letting me know about gorilla glue. We have a tube and have used it on small jobs where the glue wouldn't show (inside a cabinet). Never knew it was so messy.

The mirror is currently in our shed and it's a winter wonderland here, so I haven't had a chance to examine the back recently. I know that the paper covering the back tore when the mirror collapsed, but I'm guessing that's not a big deal.

My husband is the hanger upper in the house, and he always hangs heavy things by the D-rings. He was ready to chuck the thing because of the weight of the mirror, but I think I can convince him that with the correct reinforcements, the mirror is salvageable.

Thanks again and I will let you know how it turns out.
kimmie

From the picture I'm a little shocked that they did not think they could repair it.

I can only echo Lilah's excellent advice - her suggestions would definitely be your best bet!

Perfect application for a Kreg Jig.

L-brackets should work - just make sure you are screwing them into the thickest part of the frame and drill pilot holes so the wood doesn't crack. You might still put a little wood glue (the basic yellow stuff) along the joint too just to fill the space up more than anything else. Wipe away any extra that oozes out with a damp cloth. Also, though you probably already know this it should still be said: the D-rings should be placed on the sides of the mirror, not the top edge.

Agree with Lilah about gluing and using corner braces. Good luck!

I second the Kreg Jig sentiment. It's tough to tell what the original constructio was, if it was just glued, if it had some of those cheapo metal biscuits, or if it was constructed properly with some other method. the only way to keep this from happening again if the mirror is heavy is to put some sort of a backing on it, and make sure you hang it properly this time. 1/4" ply is fine, I would probably still kreg jig or glue & corner clamp the corners together before gluing the whole thng to a piece of ply I'd avoid l brackets like the plague, as they do not pull the corners together, they only provide separate forces in the x and y directions, and aren't going to get anywhere near the holding power that glue and/or a kreg screw would.

Kreg Jigs work GREAT, Ive used them for years. If you have a biscuit cutter (the woodworking tool not kitchen tool) I would add a #10 biscuit to each join for added strength and the us the kreg as the clamp.

I third the L brackets suggestion. One additional tip.

Pre-drill your holes very carefully. To achieve a tight seam you will need to get your screw exactly centered in the screw hole. To give yourself some wiggle room you can also cheat your pre-drill hole in the screw hole to the outside side of the seam your are joining. I hope that makes sense!

I'm agreeing with ahae5d and say biscuit it.

Alternatively, you can build a 1/4" thick plywood frame the same size but ~1/2" smaller in width so that it doesn't show, glue and clamp the corners(to get the tight initial seam), then attach the plywood frame to the back with good countersunk wood screws (I recommend Spax brand) in pilot holes every 12" o.c. or so.

probably overkill, but hey, it won't fall apart the same way again.

Find a better frame shop, we do stuff like this all the time where I work and while we'd charge more for a gigantic frame, it's usually not more than $20.

What we'd do:

Take it apart completely, pull out any nails, v-nails, those little plastic or metal butterflies or whatever they used to join it. If we can, we'd trim the edges just so slightly to clean it up. Then wood-glue and clamp it for a bit, then underpin it with a v-nailer and put an L bracket on the back.

I don't like making mirrors any heavier than they already are so I'd stay away from the plywood backing.

For hanging, go with a 4 point hanger to distribute the load and the biggest wire you can find and use 2 nails a couple feet apart.

But if it's plastic, it was worth the $35 for the big sheet of mirror glass but that's it.

The easiest way to build a frame is to use wood glue and a really long ratchet tie. Just apply the glue, put a layer of plastic around the corners, wrap the ratchet along the circumferance, and tighten.

Depending on the wood, the glue bond may be stronger than the wood itself. Since you want it to be safe, you can:

1) nailgun the corners.

2) L brackets.

3) inside back brace with wires. screw eyelets into the middle of each length of wood on the back, so 1 on each side. string a framing wire from one eyelet to its opposite and tighten, then the do the second set so that the wires cross.

Hi I'd add that you need to scrape any dried up glue from the meeting surfaces before re-gluing. Glue sticks well to wood but doesn't stick to dried glue. I would also suggest CA glue for the frame itself - it is a type of crazy glue that uses a spray activator to harden instantly. Put glue on the meeting surfaces, and when they are just right, spray the activator. Careful, don't wipe the activator when it's wet or you'll mar the finish. Also, careful not to glue your fingers - it gets really hot when the activator hits. Any glue that bubbles up can be scraped gently with a razor blade, and touch up with rub n buff like someone else said. You can do angle braces or plywood to reinforce, and get a very strong and reliable method of hanging. If you have a piece of plywood cut, exactly square, it can guide you in getting the frame exactly square when gluing up as well.