Drilling Tempered glass - possible ???

[SkiprJohn]

"You are a better man than I DelMarrey."

I broke two glass windows before I gave up.

Regards,

JohnL

Originally Posted by bstreep

As noted above, aquariums are often drilled. HOWEVER, drilling the tempered sheets adds a whole nuther risk level. I had my 215g tank drilled (3/4" glass) by a pro, and all was fine. BUT, you have a decent chance, even with a pro, of breaking the glass. They use diamond hole saws with a special compound for cooling and lubrication. And, a very light touch... It took an hour a hole to do my big tank.

Just one problem aquariums are NOT made of tempered glass so it is completely irrelevent to the discussion...

[MidLandOne]

Originally Posted by GreatKetch

Just one problem aquariums are NOT made of tempered glass so it is completely irrelevent to the discussion...

Had been wondering about that as though has been quite a while now since I have had aquariums they were all made from plate glass, not tempered/toughened. Maybe something has changed due to the danger from shards of glass if there is a breakage?

As far as I know tempered/toughened glass cannot be drilled. As I understand it, it is one of the very few materials that cannot be cut by even water jet cutters without breaking.

[MidLandOne]

Originally Posted by MidLandOne

Had been wondering about that as though has been quite a while now since I have had aquariums they were all made from plate glass, not tempered/toughened. Maybe something has changed due to the danger from shards of glass if there is a breakage?

Have answered this for myself now - toughened glass is used too, design for the thickness required takes into consideration its extra strength, but like windows, etc states that the component sheets must be cut/drilled before toughening.

[James S]

I'm sure it would be a bit $$$ but what would a water jet do to tempered glass?
I think it would shatter...but not sure.

[ribbony]

Well that idea got shattered

Better glue and fabricate alternatives. I kinda like the glue idea and had not given that serious thought before.

[bstreep]

Originally Posted by GreatKetch

Just one problem aquariums are NOT made of tempered glass so it is completely irrelevent to the discussion...

Well, sir, you are TOTALLY wrong on this FACT. In this case, you just don't know what you are talking about.

Now, I WILL grant you that not all aquariums and not all sides of all aquariums are tempered. HOWEVER, many here in the US ARE tempered. You can build a stronger tank with thinner glass that way.

In the case of my 215 gallon tank, I called the manufacturer, gave the rep the serial number of the tank (yes, the good ones are serialized), and they let me know only the bottom of my tank was tempered. The sides are 3/4" glass, so tempering wasn't required. It has several holes drilled in it - and they were drilled before tempering. I needed some extra holes...

How do I know that many tanks are tempered? Well, I worked in one of the US's largest retail stores for 8 years. When tempered tanks made their first appearance, the shop owner set up a 55 to show off. Unfortunately, no one had told Lenny that after a number of wacks with a hammer it will finally give way. It was a funny moment when 55 gallons poured onto the floor...

[bstreep]

And, just in case you don't believe it, here from the FAQ from Oceanic - the premier aquarium manufacturer:

Oceanic Systems | Education | FAQs?

And from Perfecto/Marineland, the largest aquarium manufacturer in the US:

http://www.marineland.com/sites/Mari...um%20Specs.pdf

You will see that my crappy 55 gallon tank is tempered on ALL SIDES and the bottom.

[RBEmerson]

Drilling or otherwise modifying tempered glass? In a word, NOWAY! When it's annealed, a tough "skin" forms on the outside of the glass, but that skin is just that. It doesn't exist throughout the glass' thickness. The snap reaction, then, is to think "well, just get through the skin and 'easy-peasy' from there". Not so! The annealing process sets up strains throughout the glass; the tempered skin holds them in check. Drill into the skin far enough and the glass can literally explode as the stresses are relieved. In short, drilling tempered glass is unsafe! It's not the same as drilling simple window glass.

All work has to be done before the glass is annealed. Oh, yeah, it helps to remember that annealing will probably change the dimensions of the glass. Some annealing shops are not very good about holding their dimensions after annealing is complete. Pick your shop with care.

[Bloodhound]

Annealing is a process that holds glass at a high temperature for a longish time (hours) and slowly cools it. It removes stresses. Tempering creates lots of stress and is the way automobile windscreens were made before seatbelts. When a passenger in the suicide seat was projected through the windscreen, it shattered into a million pieces and the passenger was killed when he/she hit the ground or tree outside the vehicle rather than breaking his neck upon impact with the windscreen itself. There used to be many a pile of 1/8" x 1'8" pieces of glass on the sides of the roads in rural Australia because a flying stone shattered the glass too. I've punched out a couple of broken windows myself and added to the "litter".

In any event, I don't think you're likely to be very successful "drilling" a hole through tempered glass. If the piece has value to you, best attach the hinges with an adhesive (possibly even with the adhesive used to attach rear view mirrors to windscreens!)

[Christian Van H]

Ribnony...Post a pic of the hole pattern, just in case we might know of a suitable latch or a slick fix. There are some INCREDIBLE fabricators on this forum. Good luck, Chris

[GordMay]

Originally Posted by Bloodhound

... best attach the hinges with an adhesive (possibly even with the adhesive used to attach rear view mirrors to windscreens!)

Which are usually methacrylate based (super-glue).

[RBEmerson]

Tempering and stress... much of my info on the topic was picked up while coping with a bungled tempered glass counter top that had to be drilled to fairly tight specs (one potential vendor said anything under +/- 1/2" was out ). That and a friend, formerly at PPG (Pittsburgh Plate Glass), who designed glass curtain walls for high rise buildings. He had more than one occasion where a sheet of tempered glass blew up "only" because of a scratch as a piece scraped against a bit of structural steel, resulting in "lost time" injuries. Anyway, agreed the bottom line is drilling tempered glass is out.

[bobdobbs]

I'm sorry for the awful sketch.

Without seeing the hatch or the latch ... here is what I picture:

You could make an adapter plate with studs on one side to fit the hole pattern of the glass and studs on the other side to match the latch. You could fancy the plate up a bit. Fillet the the corners or whatever. Use press fit studs or welded studs or just tack weld some counter sunk screws to hold them in and use acorn nuts to make it look nice. I suspect you would want a backer plate on the underside of the glass spread the load of the nuts.

You could get creative with it and not worry about drilling the glass.

[RBEmerson]

Uh... I'm not sure if this qualifies as a fool question or a damn fool question but... why not use polycarbonate instead of tempered glass? As long as you don't let people smear suntan lotion on the surface (scary what that does to polycarbonate - makes ya wonder what it's doing to you... ), it's amazingly strong stuff and much, much, much easier to work with. Additionally, tempered glass can fail (often spectacularly) when scratched or dinged. In the same setting, polycarbonate just looks scratched or dinged and that's it.