Mirrored, Frameless, Full Overlay Door Details

Here's a good discussion of assembly methods, adhesive application, and hinge and catch details for a vanity door with a full-face mirror on the front. January 1, 2012

I have the task of building an upper vanity cabinet that will sit on a granite top. The design calls for mirrored panels that are veneered to overlay frameless doors. We are planning on using 1/4" glass. I need to attach the mirror to the plywood doors. Right now I am planning to use the provided tube of mastic from the glass shop.

Can I use 1/2" ply for the substrate door panel? I will be using cup hinges. So the mortise for the hinge is the same depth of the 1/2" ply that will essentially leave me with a hole clear through the panel.

In my mind, scary. The cup hinge needs the bottom of the mortise as it is a part of the design to bear against it. So 1/2" to me will not work.

Forum Responses
(Cabinetmaking Forum)
From contributor S:
Go ahead. We use 1/2" Baltic birch. Never a problem with the hinge. Hinge is less than 1/2".

From contributor J:
Use the Inserta clip top and no dowels. I would mastic the doors and let cure flat for as long as possible. If you glue the doors and set, in a few days it will not take much heat to make them sag.

From contributor D:

The Salice Series 100 hinge features a cup depth of only 8mm. This would fit nicely in your 1/2" plywood with 5mm to spare. It is available in a 105 degree opening and a 155 degree opening. Many medicine cabinet manufacturers prefer the 155 degree for doors such as yours.

From contributor B:
Why not use 3/4" instead of 1/2"? Depending on the door size the 1/2" ply may not give you the integrity or flatness of 3/4". You will get a lot more deflection of the mirror on a thinner door blank.

From contributor D:
Another way to do this is to "lip" the glass over the side of the cabinet and have the plywood backing inset. This is very common and as a design element gives a very sleek look to the piece. Attached is a drawing to give you the concept. The dimensions on the drawing are not exactly the same as yours but it should give you the concept of the possibilities. Also, the drawing shows an applied edge on the glass that would not be necessary.

Drawing PDF

From the original questioner:
Thank you. It seems I may go with 1/2" ply. I feel the 1/4" glass will work with the 1/2" ply and make a decently flat panel, especially if I glue up on something flat and let set till dry.

We would like to incorporate a touch latch as well. Not thinking this is possible with cup hinges. Thoughts? It would also be nice to use some form of soft close hinge since it will be a heavy door. 12 lbs of glass on 3.5 square ft. 1/2" ply, so maybe 14~15 lbs. total.

Adhering the glass... The mastic tube says dollops. Fine for the flanking mirror on the adjacent walls, but glass to ply, I am thinking notched trowel. Hoping to keep the gap between ply and glass minimal.

Sorry to have made such sweeping generalizations on the cup hinges. When I was doing more sheet good work I used only Mepla, as it was easy to get from my distributor and I pretty much stuck with one or two hinges.

From contributor D:
You will need to pick either a soft close hinge or a touch latch type. You can only use one or the other. If you use a touch latch you will need to use a free swing hinge. A self closing (or soft closing) hinge will fight with the touch latch and not allow it to open the door. An alternate solution to the touch latch is the Salice push hinge which acts like a super touch latch, opening the door entirely. The self opening feature is built into the hinge. Typically, a touch latch only opens the door 1/2" or so.

If you decide to go the soft close route, be careful of the cup depth requirement. The Salice Series 100 Silentia soft close hinge requires a 12mm cup bore. You may be able to get away with this if your 1/2" plywood indeed measures 13mm.

Other soft close hinges on the market also have cup depth requirements (Blum = 13mm). If the cup depth is a problem, you could stick with the standard self closing hinge and add a Salice Smove soft close piston.

From contributor L:
Use 5/8" plywood or veneered MDF, and drill the hinge holes first, before you apply the mirror.

From contributor D:
Agreed. The MDF would probably be the best substrate for this project.

From contributor R:
I recently finished a project like this. I used MDF, veneered the back and edges, sealed and sprayed all sides, used mirror and Blum soft-close hinges. No problems whatsoever. I have another coming up. I will use the same process, but use the Salice push hinges and latch system.

From contributor E:
Did it for a medicine cabinet. 3/16" mirror mastic to 1/2" MDF with 35mm all the way through the board. I did use dowels (obviously drilled before the mirror was applied). Two years later and the door has not sagged. I know this because I was at that customer's house about two months ago doing some more work and I know she wouldn't have adjusted anything, as she claims to have two left hands.

I also used touch latches from Hettich, I think. You need free swinging cup hinges without the spring that makes it self close. Works great.

From the original questioner:

Good call on the free swinging cup hinge. If the customer wants to upgrade to the super touch latch then maybe head that way.

MDF... I live on the island of Hawaii. MDF isn't a preferred material for me here. I used it back in Maine. Not so much here. High RH mostly.

3/16" mastic, troweled on? Still curious if the bottom of the 35mm mortise is integral to the design of a cup hinge. Does the hinge need or gain advantage from bearing upon this bottom face? My opinion is yes.

From contributor C:
I worked in Germany for 4 years as a cabinetmaker. As you might guess, they are super technical. So to answer your question about the bottom of the 35 mm hole being important, no... It's the fact that it is a mortise. Whether it is 30 or 35mm is not of crucial magnitude. Just like a butt hinge or any other kind of mortise. It is the screws plus the mortising that makes it a better connection. Imagine the cup hinge had no screws. It would still hold fine if it weren't for the action of opening and closing the door. As far as the 35mm depth, the deeper the better to a certain extent. To what extent I can't say because I'm not an engineer. This is how it was explained to me... My uncle was the VP for Hettich, by the way.

From contributor E:
No troweled mastic. I just blobbed it like caulk. Stripes of caulk and spots between the stripes.

From contributor D:
Hinge cups are not 35mm in depth. The 35mm is a common diameter of the hinge cup hole. 40mm and 26mm diameters are also quite common. The depth of hinge cup boring varies with manufacturer, but commonly range from 8mm to 13mm. The depth of the hinge cup bore is usually a function of the application. With deeper door edge profiles being popular in some regions, a shallower cup depth can be quite advantageous. The popular soft close hinges on the market require a deeper drilling to accommodate the soft close mechanism.

From contributor E:
My bad. I realize the diameter is 35mm and not the depth. Point is it is a mortise and the depth is not so important if we are talking mm. I also get it that the technicalities of some of the soft-close type hinges needing to be bored deeper. That wasn't the point I was making.