Grooves Made In Tempered Glass

If the grooves are made before heat tempering, yes; if you try to make the grooves after tempering, the glass will likely shatter. Explosively.

Why not get the glass laser engraved?

There are engravers everywhere you go.

Or sand blasted: do people still etch their registration (number plates) in their car windows?

No. They just put little stick figures of their family and pets on there.

Can you laser etch tempered glass?

If the groove is 1-2mm deep, will the glass shatter?

This may be a dumb idea, but why not just call a glass shop?

I did, it was a dumb idea!.......

Both my local shops didn' have any experience of working with tempered glass. They usually just order it in.

I'd go up the chain and see if there is someone at a supplier that is a tech.

I have never seen tempered glass altered in any way after heat treating.. The issue is surface tension, break the surface tension and instant crystals or pieces. Do all your fancy work before the heat treat but it may act as an extrusion where all cross sections should be equal for proper contraction upon cooling to avoid distortion which on glass may lead to the shattering issue you are trying to avoid.

Not a glass specialist but know this much if any work has to be done on glass, it is before tempering it. Once the glass is tempered, we try to cut, drill or cut any groove etc. it will shatter in to small chips.

Warning: If the glass is already tempered, and you put a groove, or even a nick, in the surface, depending on how thick the tempered surface is, the result can be an EXPLOSIVE bang, destroying the glass with fine, sharp glass particles 'everywhere,' on your shirt, in your face, on the floor, on your bench tools, and worst of all small glass dust and particles in your eyes requiring a visit to an eye doctor to carefully remove the glass bits. It is a mess to clean up the fine glass particles. Yes, I know by experience ... don't damage the surface of tempered glass, even tho the glass is very strong from tempering. Shape the glass first, then have it tempered.

Are we all talking about the same kind of tempering here?

"Tempering creates imbalanced internal stresses which cause the glass, when broken, to crumble into small granular chunks instead of splintering into jagged shards. The granular chunks are less likely to cause injury."

From http://en.wikipedia.org/wiki/Toughened_glass

I suspect that the Original Poster is trying to get an idea of the differences in the effect on the strength of the glass by compromising the edges of the glass compared to compromising the large flat surfaces.

I think Hydrofluoric acid, will itch even tempered glass. But to do this masking, screen printing like services has to be considered, only experts can handle HF like harsh acids.

've googled and confirm itching of tempered glass using Hydrofluoric acid:

http://www.instructables.com/id/Glass-Etched-Glasses/

If you wish to experiment on tempered glass, wear EYE protection and have a broom and dustpan handy.

If you need to modify a piece of tempered glass, you must remove the tempering by annealing FIRST.

http://en.wikipedia.org/wiki/Toughened_glass
http://en.wikipedia.org/wiki/Annealing_%28glass%29

THEN modify the piece of untempered glass. After ALL modifications are complete, have the piece (re)tempered.

Good Luck!

Tempering the glass removes the internal stresses. Two characteristics are necessary to cause glass to break. Those characteristics are stress and a flaw. Tempered glass can be full of flaws and it won't cause any issues because there is no stress.

The answer to your question is yes, you can form glass when it is hot. How it cools and the flaws you introduce, if any, will determine if you will have problems. If you need high impact resistance, you introduce stress without flaws. If you need resistance to breakage, you anneal (temper) the glass, but that relieves the stress. Glass blowers learn some of this through trial and error. Lamp makers use the science to make sure their products don't blow up in the hands of their customers.

What problem are trying to imagine solve?

I've had to manufacture a lot of strange items over the course of my life and would say that this doesn't seem to be too difficult to accomplish.

1. What is the purpose of the "Groove"?
2. What are the tolerances of said groove?
3. Can the grooves be done before tempering?
4. That small piece of glass is so cheap, why not experiment with a diamond abrasive wheel lubricated and cooled with water? (Wear appropriate safety gear!!)
5. There is more danger working with strong acids and lasers than old methods like grinding and sandblasting.
6. KEEP IT SIMPLE!

You must surely know someone in your business community that can accomplish this task. They will probably tell you "No Guarantee's" but at least they may succeed, and if they fail then lesson learned.

This seems similar to a biscuit joint for wood, am I close?

I'm not an expert, but it seems the 90mm x 90mm size is pretty small for tempered glass, which is something I've always thought was done to increase the stability of large glass plates, and so they did not break up into dangerous shards, (think tall buildings' glass windows).

One solution is to etch using Hydrofluoric Acid. This is used to etch Pyrex glass containers. I remember that markings on Pyrex Glass beakers and Jars in Chemistry labs had markings etched with H2F. (Pyrex glass is toughened glass).

Would it be possible to laminate some thin pieces to create spaces where you want the grooves/slots?