Frame techniques for antique mirror

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CoPhotoDude

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Hello. I mostly frame my own artwork for sale at shows and for my clients. I have been asked to frame a 30”x65” horizontal mirror. I am hoping for some technique guidance.

At that size would it be better to do a corner brace from masonite or to cover the entire back of the frame with masonite? If the intire back, should the masonite sit within the frame like a foamcore backing or be screwed in to the frame (as if it were taking the place of the backing paper)

If iuse french cleats is it better to attach those directly to the frame (top and possibly bottom) or to use a thicker backing material like 1/4” plywood within the frame and attach them to that? How thick must whatever wood i use be for secure attachment?

For safe and secure framing are there any other bits of assembly advice i should follow?
 
Some things are going to depend on where your client wants to hang the mirror. IE: a living area or a humid bathroom. If it's just going in a dining room or living room, I sometimes just back with foamcore because it's nice and soft on the mirror, and doesnt add much weight like plywood does. If it's going in a bathroom, back it with corrugated plastic like coroplast so the backboard doesn't collect and hold moisture. Use offset clips to hold into a very sturdy frame rather than points which could bent loose. If your client insists on a thin profile, construct a strainer frame with pocket screws to affix to the outer moulding. This will be the actual frame it hangs off of. Otherwise, you can beef up a normal frame with metal corner braces for extra security. As far as hanging hardware, I would probably go with cleats. You can certainly put them on both the top and bottom rails to distribute the weight and strain better
 
this will actually go in a business lobby.

if I add corner reinforcements should I expect cleats top and bottom to be sufficient on a standard-ish white wood or pine 2" frame?

I hadn't thought about offset clips. I have tons from framing canvases, would the clips go immediately behind the mirror and then backing over that, or make my package with foam core/board and clip all of that in together so clips aren't in contact with the mirror?
 
If you don't want to use wooden cleats, see if you can get product called Z-Bar (or EZ-Bar). It's aluminum and works well if the frame is on the narrow side. Sometimes wooden cleats can be weakish when they are narrow.
 
CoPhotoDude said:
this will actually go in a business lobby.

if I add corner reinforcements should I expect cleats top and bottom to be sufficient on a standard-ish white wood or pine 2" frame?

I hadn't thought about offset clips. I have tons from framing canvases, would the clips go immediately behind the mirror and then backing over that, or make my package with foam core/board and clip all of that in together so clips aren't in contact with the mirror?
Click to expand...
Here's the kind of corner reinforcement I had in mind:
I get mine from 888
1740423264698.webp


Should that be sufficient? Idk, probably? It really and truly all depends on the frame. Thinner 2", maybe not. Deeper 2", sounds a bit better. Much of the strength lies in the over-all surface area of the moulding's cross section when cut. Idk if there's any formula for it, I just feel it out and pray for the best.

And yes, make your package with foamcore and then clip it in. A big part of the backing is to protect the mirror back from getting chipped from the metal offsets. Also, use them backwards(?)--ie where they extend the rabbet on a canvas, turn them inwards to reduce the rabbet and hold the foamcore snug against the mirror inside of the wooden frame.
 
Bruce Papier said:
If you don't want to use wooden cleats, see if you can get product called Z-Bar (or EZ-Bar). It's aluminum and works well if the frame is on the narrow side. Sometimes wooden cleats can be weakish when they are narrow.
Click to expand...
Z Bar is my strong preference always. I don't like wood ones.
 
If you were to adhere a strainer frame to the back of the mirror and put your aluminum cleats on that or integrate a French cleat, the strength of the frame becomes irrelevant.
Note that French cleats can be engineered to support a much greater weight than Zbar.
 
I have several unanswered questions for this project:
  • what type of mirror - 1/4" plate glass, acrylic, 1/8" glass
  • where is the mirror with respect to the traffic flow - is it over a table or other furniture or in a low traffic alcove
  • will this commercial area be used by youngsters or the elderly - IE medical offices
  • how will it be secured to the wall - anchors or screws in drywall or other wall material
  • one thing to remember is that a full sheet of plywood or other construction material that is mechanically fastened to the back of the frame will give rigidness to the entire frame system. Large mirrors have used rigid backings for several centuries.
  • you might want to consider it being "bolted to the wall" or use security hardware
 
wpfay said:
If you were to adhere a strainer frame to the back of the mirror and put your aluminum cleats on that or integrate a French cleat, the strength of the frame becomes irrelevant.
Note that French cleats can be engineered to support a much greater weight than Zbar.
Click to expand...
what would you use to adhere it so that you were highly confident there wouldn't be a delamination?
 
JFeig said:
I have several unanswered questions for this project:
  • what type of mirror - 1/4" plate glass, acrylic, 1/8" glass
  • where is the mirror with respect to the traffic flow - is it over a table or other furniture or in a low traffic alcove
  • will this commercial area be used by youngsters or the elderly - IE medical offices
  • how will it be secured to the wall - anchors or screws in drywall or other wall material
  • one thing to remember is that a full sheet of plywood or other construction material that is mechanically fastened to the back of the frame will give rigidness to the entire frame system. Large mirrors have used rigid backings for several centuries.
  • you might want to consider it being "bolted to the wall" or use security hardware
Click to expand...
• I'm told "antique mirror" i do not have it in hand yet - I haven't accepted the job until I figre this out.
• I do not know the traffic flow but I assume "lobby" means pretty much anyone can walk by
• the space is open to the public
• I have told them at this size it needs to be direct to studs and they need an appropriate contractor to install, not me.
• plywood - that was my thought. would you put the plywood IN the frame (within the rabbet) or ON the frame (screwed into the back)?
• I have suggested that to them too. in a commercial space it needs to be well and properly attached.
 
  • "antique mirror" can even be 3/8" thick glass.
  • definitely attachments utilizing the studs in the wall. With a method to deter any movement (not just gravity)
  • Note hospital environments have their own codes for hanging anything on a wall.
  • From an engineering standpoint, screwed into the frame moulding would be the best method. Full mechanical attachment vs "floating in the rabbit".
 
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