Specifying Glass for a Table Top
tempered or untempered glass? Furniture makers exchange views. June 20, 2005
I have recently been asked by someone to add a protective glass cover on a veneered table top. Does anyone have experience with this? I’m not sure if the glass will cause any problems or not? I have a thought that the lack of air circulation or sweating might be a problem? Any suggestions would be appreciated.
(Furniture Making Forum)
From contributor P:
I don’t think that putting the glass directly onto the surface will cause any harm. For my money, I'd bet that it would be no different than if you built a 2-piece hutch and put the upper unit base directly on top of a veneered lower unit. The glass will also help to hold the surface flat so there should be no warp or veneer lifting issues. Glass by itself will not cause wood to sweat.
Adding anything between the glass and the surface is a sure way to break the glass. Glass absolutely does not flex - it breaks. Tempered glass explodes into little pieces when it breaks due to flex.
From contributor R:
I would not use tempered glass at all. The only reason you use tempered glass on anything is to protect a person from getting cut by a large piece falling on them.
Tempered glass is too brittle and it will break if someone hits it with a drinking glass too hard or bangs a ring on it. Un-tempered glass will flex, and I would recommend putting felt pads around the edge to support it and keep it off the wood surface.
From contributor W:
I made a 54" diamond 1/4" plate glass top made for a new Teak dining table a while back. This top over the years has acquired numerous small chips around the edge and on the corners of the curved leaves, but they haven’t affected the use or function of it.
I would not temper the glass. If it was tempered, each one of the minor chips may have ended up as a complete crumbling of the glass.
From contributor T:
Laminated glass would ease the safety concerns, but the edge does not have a very nice look to it. I would suggest looking into using plate glass, regardless of the application. You can simply add a clear or tinted film to the bottom or back side, which will hold it together in case of upset.
From contributor H:
I think that most of the reasons for having pads has to do with the glass not sticking to the top, rather than having an air gap. I've actually had something come into the shop where the glass was completely stuck to the finish. I'm guessing either something got on the top, or the sun softened the finish and the glass sunk into it. You can get discoloring under the pads if they're never moved though, so I guess there's no perfect solution.
From contributor J:
For tables the glass could be either tempered or standard glass, as long as the edge of the glass is held back from the edge of the top for sideways impacts. Dropped items shouldn't be a hazard unless the top is not solid across surface. Areas like upper cabinets would need a proper thickness with the possibility of a laminate in-between for shard retention-building facades.
The shape and quantity of clear pads between surface and glass is vital. Wide and thin is my choice. A general rule for perimeters is 1 pad for every 12" and inside area 1 for every 4 square feet. Also, it is of top priority to let the finish cure for at least 1 month before glass is installed.
From contributor S:
I do a lot of built-in desks and work centers, and I like to cover the tops in 1/4' glass. I don't use tempered glass - cost being the main concern, and the lack of need being secondary. The spacers are designed to keep the glass from sliding on the top. I don't use spacers, instead I prefer to recess the glass top, usually with a band of contrasting grain or species.
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor E:
I used quarter inch regular glass and stabilized it with rubber patches (the ones used on bicycle tires). On dark wood this works perfectly.
JAMES @ FASTGLASS' COMMENT:
FOR FREE STANDING TABLE TOP'S OUTSIDE ON YOUR DECK OR PATIO WHERE THE WIND WILL BLOW OVER THE PATIO TABLE BECAUSE OF THE UMBRELLA & BECAUSE OF THE 2" HOLE DRILLED IN THE GLASS FOR THE UMBRELLA- YES, WE WOULD ALWAYS USE TEMPERED. WE USE RAW ANNEALED PLATE GLASS FOR ALL PROTECTIVE TABLE TOP'S FOR THE REASONS ABOVE.