Framing Big Mirrors

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Shayla

Shayla

WOW Framer
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Customer wants vertical mirror, around 42 x 96". Most likely, will suggest attaching mirror to wall, and hanging frame over it, but not bearing weight. But, if they do want it hanging from the frame, anything I should know? Would be using Z-Bar and hanging from wall studs, unless there's a better way. And, that size, would a 1/4" mirror distort imagery?
 
Skin the back of the frame with a sheet of 1/4" luan plywood...actually two pieces joined together as the mirror is 96" and then you'll need more for the width of the frame... making the whole thing weight bearing instead of just the corners.

Not sure about image distortion, but I would think that 1/4" is thick enough to not give any distortion.

Z bars are the best for this and as the screw holes are 4" apart, you'll hit at least 3 studs, just make sure screws are put into ALL of the Z bar holes regardless of stud or not.

Again, it's about distributing the weight load.

Good luck lifting this monster!!

Don't forget to charge for the 2 young studs you'll need to hire to move this thing in the shop as you work.
 
Mirror's gonna weigh around 90#.
 
I come up with the mirror weighing something like 112 lbs.
Regardless, that plus the weight of the frame would be too heavy for Z-bars.
Strainer with cross bars and an integrated French cleat would be better.
The challenge of hanging a frame on a mounted mirror is building the mount out enough so the mirror fills the rabbet. You also can't count on the walls being flat.
 
1/4" mirror usually calculates @ 3.27 lbs/sq ft, I believe.
 
wpfay said:
I come up with the mirror weighing something like 112 lbs.
Regardless, that plus the weight of the frame would be too heavy for Z-bars.
Strainer with cross bars and an integrated French cleat would be better.
The challenge of hanging a frame on a mounted mirror is building the mount out enough so the mirror fills the rabbet. You also can't count on the walls being flat.
Click to expand...
Thanks for the reminder about wall flatness. And I did have the rabbet depth in mind. Figured the easiest fix was to mount the mirror onto something that gives it the right depth. (MDF? Masonite?). And that weight sounds about right.
 
Mounting the mirror to the wall and trimming it is ideal. I have a job coming up with nearly the same specifications, but the customer does not want to permanently mount the mirror. I plan to build a substrate for the mirror equal to the rabbet width minus the mirror thickness and mastic the mirror to that. The wall facing layer of the substrate will be 3/4" plywood. I will relieve much of plywood weight by cutting out two large squares side by side, in effect it will be a strainer without joints. I will cut out the squares with a vee bit on my CNC, so the edges of the cutouts can mate to french cleats on the wall.
 
Shayla said:
And, that size, would a 1/4" mirror distort imagery?
Click to expand...

Shayla said:
Thanks for the reminder about wall flatness.
Click to expand...

6mm or 1/4" mirror is pretty solid, but if pressed on firmly to a wall (using NC silicone) it can bow (think funhouse effect !).
It would normally be pressed on firmly, but not enough to bow, it should be fine.

Wall flatness is usually ok for most of these types of mounting technique.
I'd definitely recommend a top and bottom batten.
 
This is probably the best thread on the G pertaining to large mirrors:
www.thegrumble.com

Opinions Wanted - large mirror: small frame

I have a customer who is very insistent on using a one inch wide frame for a mirror that would measure 34"x58". Try as I might I can't seem to convince him to go wider. I think even with z-bars top and bottom, or z-bars on the top and reinforcements on the bottom corners, this frame is just...
www.thegrumble.com www.thegrumble.com

Maybe it could be listed under 'resources' or something...
 
Adhere the mirror to a sheet of 15MM Ultralight MDF cut to size. Since the OD of MDF sheets is 49 x 97, you will have no problem with the 42 x 96 size requirement. Then use heavy duty Z bars to mount it to the wall being sure to hit the studs with the screws. Two benefits using the Ultralight MDF - it is very flat and because it is Ultralight it is about 33% less in weight than standard MDF. It's also quite a bit lighter than plywood. Of course you will need to find a molding with a 7/8" deep rabbet.
 
Rick Hennen said:
Adhere the mirror to a sheet of 15MM Ultralight MDF cut to size. Since the OD of MDF sheets is 49 x 97, you will have no problem with the 42 x 96 size requirement. Then use heavy duty Z bars to mount it to the wall being sure to hit the studs with the screws. Two benefits using the Ultralight MDF - it is very flat and because it is Ultralight it is about 33% less in weight than standard MDF. It's also quite a bit lighter than plywood. Of course you will need to find a molding with a 7/8" deep rabbet.
Click to expand...
i've had a hard time finding ultralight mdf. any recommended resources?
 
Matthew Hale said:
i've had a hard time finding ultralight mdf. any recommended resources?
Click to expand...
I would be happy to supply a list of distributors to try around Southern California but not sure where to look in Ohio. I have 6 different places I work with, and we use quite a bit of it, and even with that, given the current situation at the ports, finding a supplier with Ultralight in stock is hit or miss. Almost all of it is produced overseas, Chile and New Zealand I believe. You may be able to find standard MDF more readily but then you are looking at about 33% more weight.
 
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