Question about heavy glass cabinet doors

[ThomasC]

As always, this is the first place I come to for advice, so here's the scenario...

I've been contracted to build a few trophy/display cabinets for a local university. Each cabinet will be 10' high, 10'-6" wide, 18" deep. The design calls for four Mission style doors with glass panels. Each door is approximately 30" wide x 96" high. The specified glass is to be 3/8" thick, tempered. When I called my glass supplier for the specs, he said that each piece of glass would be approximately 104 pounds! So my questions to you are: 1. Can traditional joinery, such as cope & stick, with a tenon or domino work? I worry that the rails and stiles may not be able to support that much weight. 2. Is there a cabinet hinge out there that is capable of this much weight? I realize it will require multiple hinges, but I don't think even a row of 35mm cup hinges would stand a chance with this much weight.

Not to pick on my architect and designer friends, but this seems like another one of those projects that looks great/easy on paper, but the logistical issues are a potential problem. In the designers' head, these cabinets will have 3/4" thick doors, with narrow (2 1/2 - 3 1/4") rails and stiles, and concealed hinges. The intent is to have as much glass as possible, with a minimum amount of frame. I'd like to think that this can be accomplished, and I'd like to stay as close to the vision of the designer as possible, within reason.

If I've left out any information that would help you help me, I'll do my best to provide it.

Thanks in advance,

TC

 

[Brice Burrell]

I'd double check that glass thickness with the designer.  I see no reason for it to be that thick.

 

[tjbier]

Even with 5 or 6 hinges that is still a lot of weight!
Can you use 4/4 stock for the doors? That would help but that glass is just too heavy to expect a door to hold up too.

 

[Jim Metzger]

I designed an 18' long by  9' high display cabinet a number of years ago and used glass shower door hinges on (6) 3' wide solid glass doors. Worked great.

Jim

 

[CABMEISTER]

That would be one beefy door for sure . The first thing that comes to my mind is maybe consider a Piano Hinge . These do come in fairly large leaf widths and can be made to look very nice with 1/2 or full knuckle protrusion if so desired.
                I am trying to rack my feeble brain because way back ,I remember having a similar project (large heavy panel ) .Details of frame sizes escape me ,but I did use the panel as frame support by cushioning the opposing corners of the panel therefore supporting the frame . Sort of like a brace . Hope that helps .      Keith

 

[jonny round boy]

I'd double check that glass thickness with the designer.  I see no reason for it to be that thick.

I agree. No reason to have the glass that thick - and several reasons NOT to...

For the metric peeps out there, or those willing to do the maths, glass weighs 2.5kg per square metre, per millimetre of thickness. So 6mm glass is
6x2.5kg = 15kg per sq. m; 10mm is 25kg/sq. m.

 

[Guy Ashley]

Another possible option is to reconsider the hinge system. With traditional butt hinges all the stress is on the side of the cabinet carcase.

It might be an option to use pivot hinges which are rebated into the top and bottom of the door and cabinet frame.

I have provided a link to Brusso Hinges but these may not be large enough but you may be able to source something similar but in a larger size.

http://www.brusso.eu/acatalog/Online_Catalogue_HINGES____PIVOT_4.html

 

[kdzito]

I'm not sure what your total contract scope of work is and the budget you have here is, but this is such a specialty item that I consider it to be a buy-out item. From my millwork/woodworking prospective doing it in-house would be my last resort.  So with this said, try Poblocki and Sons.  If their price is too high, that's okay but you may be able to get help about the feasibility and function of the display cases construction.

Ditto on the glass thickness.  This glass should be no more than 1/4" thick.  Now on the hinges, when you say concealed Soss comes to mind.  These are excellent hinges and will more than adequately support the weight of the doors.  If your door is 2/6 x 8/0, then you need 4 hinges.  Even Soss may be able to help with the specific hinge to use.

Also, not to change the design, but consider these doors to be bi-passing to slide laterally within the opening from a top and bottom track. 

Please post a rendering or drawing of this display case and I could give more comments and guidance.

 

[fdengel]

At 1/4" thick it would still weigh around 70 lbs, correct?

The only reason I can think of for the glass to be that thick would be for some sense of security / protection of the contents...

Unless they plan on putting this in the middle of a basketball court, then I could possibly come up with other reasons...

  [laughing]

 

[tiralie]

1. Can traditional joinery, such as cope & stick, with a tenon or domino work?

Maybe, but I wouldn't risk it. As others have said there is no reason for the glass to be this thick. It could be that the designer made an error or thinks this is safer.
I would look at this problem as if this were an entry door; stave core (pine) veneered with (through) mortise and tenons
I would use all the techniques that traditional door makers use.

2. Is there a cabinet hinge out there that is capable of this much weight?

As per above, I would use entry door style hinges. If the designer insists on 3/4" I  would cheat the 3/4" to 7/8 or thicker if you can.
If the designer insists on using that thickness of glass you may have to go with a pivot style door.  Rixson www.rixon.com (I have never used them) may be a good company to contact to start figuring out the best options are for heavy doors. There are a couple other hardware manufactures such as Von Morris (http://www.vonmorris.com/index.cfm) that make hinges that could support that weight, but they are pricey.
Tim

TC
[/quote]

 

[Ken Nagrod]

Thomas,

Freud makes adjustable rail and stile bit sets for just this purpose.  I own all of them.  They allow you to make tenons of any length to increase the frame strength.  They are 1/2" shank bits/sets.

http://www.freudtools.com/news.aspx?showarticle=26

 

[atomicmike]

You might look at Soss hinges as an option: http://www.soss.comhttp://www.soss.com

- Mike

 

[Brice Burrell]

Lots of advice on hinges but that's the easy part.  Making glass panel doors out 3/4" with narrow rails and stiles is the challenge.

 

[tiralie]

Lots of advice on hinges but that's the easy part.  Making glass panel doors out 3/4" with narrow rails and stiles is the challenge.

No kidding! Particularly if you need it strong enough to hold that thick glass.
Tim

 

[Ken Nagrod]

Why does it have to be 3/4"?  You can go thicker with those bits I referred to.

 

[ThomasC]

Thanks for all of your helpful replies so far - lots of good ideas! I have not heard back from the designer yet, so I don't really have any updates. I have shared many of your suggestions with the designer, so hopefully a good plan of action will be in place soon.

Thanks again for all the help - much appreciated!

TC

 

[BMH]

You could use the glass thickness to your advantage. Use heavy hinges that are use on glass doors on the glass and use the rails and stiles to hide them. A different way of looking at the problem.

Bruce

 

[tiralie]

You could use the glass thickness to your advantage. Use heavy hinges that are use on glass doors on the glass and use the rails and stiles to hide them. A different way of looking at the problem.

Bruce

Bruce:
Cool idea.
So if I understand you correctly essentially add a (non structural) frame to a hanging glass door rather than add glass to a wooden framed door with glass inset.

Tim

 

[harry_]

Guys, you are all way over thinking this.

This is really not much different than a glass/aluminum storefront door, of a significant amount of its structural strength is derived from the glass itself. Storefront are rather flimsy with the glass removed.

Storefront doors have 'tweaking screws'. As long as you can build the wooden frame to stay together, the glass itself will do all the real work. If all the stiles and rails are dominoed or doweled, and your hinge side can hold all the weight, the 'tweaking screws' will adjust the frame to square referencing from the glass itself.

The tweaking screw goes in the upper rail a few inches back from the strike/latch side of the door. Since it is presumed that the wooden frame will stay together. all the weight of the glass essentially sits on the hinge side bottom corner. it is the frame itself that will want to sag out of square. so you just run in the screw down into the edge of the glass. You WILL need to put _something_ in between the screw and the glass. Almost anything will work, piece of plastic shim or whatever. this prevents the screw from trying to cut the glass and inviting a crack at that point.

This is a standard thing in glass/aluminum storefront doors. I cant see any reason for it no to apply here.

From a personal perspective, I would not use dowels and would only use dominos if I was going to attempt using them as a draw mortise. Additionally, what if the glass ever needs to be replaced? With that in mind, I might use lightly sanded dowels to join the strike side stile to the top & bottom rails with some sort of decorative/functional thing to screw the thing together. You would want that stile to come off, but only when you say so.

 

[BMH]

Tim,

Your are correct you can add a non structural frame or as Harry proposed the aluminum frame door technique. In that case you will probabbly have to mount the cabinet doors on a pivot system to prevent sagging.

Bruce