Drilling Tempered glass - possible ???

[ribbony]

We have some nice big deck hatches with tempered glass in them, but the holes in them do not match any latches we can find for securing them. So we need to drill them to fit some different spacing of bolts. Can you drill this material (never tried to drill glass apart from a laminated car windscreen & that was pertty hard) ? They are not removable from the vessel without a major operation. 4 holes would be the minimum to get fatenings in place.

[Morgan Paul]

I would think if you are trying to enlarge existing holes you will have to use a diomand file

Diamond Drill Bit & Tool

Good luck man.

[GordMay]

Originally Posted by ribbony

We have some nice big deck hatches with tempered glass ...
... Can you drill this material ...

NO.

Tempered glass is regular glass that has been heat treated to increase strength and thermal shock resistance to prevent injury by changing the break pattern.

All fabrication (cutting, drilling, edging) is done prior to tempering.

The manufacturing process of making tempered glass results in the glass having a large amount of stress between various portions of the glass. Highly tempered glass will often crack at the stress points near the hole. Since the amount of hidden stress increases with the degree of temper, the success rate of drilling tempered glass reduces with the increase in glass temper.

There is no way to know the amount of temper in a piece of tempered glass, so there is no way to evaluate the amount of risk involved in trying to drill it.

Therefore, experts DO NOT RECOMMEND attempting to drill tempered glass.

[irwinsailor]

Having worked in a glass company for 23 years I can say that once glass is tempered there is very little that you can do to it. It will never take being drilled.

[Lodesman]

Can you drill a latch to match the holes that are in the glass?

[AnchorageGuy]

I too would suggest trying to modify the latch rather than modify the glass. If you study it a bit you might find this easier than you think.

[SkiprJohn]

I once tried drilling tempered glass. Did everything I could think of (including diamond bit) but ruined two rear windows of a Renault Le Car trying to fix someone else's car. Good lesson for me. You just can't drill tempered glass.
Regards,
JohnL

[Weyalan]

Can you make a plate that bolts on through the existing holes, that you can drill and tap to suit your latches?

[ribbony]

Now that is a convincing thread of reponses. I will not attempt to drill as it looks like broken glass will be the result. Fabricating latches to fit the holes will be a challenge (holes too close togeather), but that is what we have to do.


Thanks for the feedback.

[Ex-Calif]

What about bonding the latch straps in conjunction with the too close together holes?

[Bloodhound]

There is probably no need to bolt these parts together. Tropical fish aquaria are consrtucted from sheet glass glued together with silicone (yes, that horrible crap that should normally not be at a wharf let alone on a boat). But once bonded, the parts will be almost impossible to separate except using a special silicone remover. Amazingly strong as long as the joining film is thin (thick gobs seem to tear, but thin films are very tough).

[Zach]

Hmm...

In the hotrod world, folks use sand blasters to cut tempered glass windows when building chop top cars.

I wonder if you could use a sand blaster to blast some new wallowed out holes?

[delmarrey]

Tempered glass can be drilled but not EZ for your application. The problem is if the drill catches or binds, it's all over.

Below are some successful demos of tempered aquariums (the bottoms are tempered, the sides are not) but they are actually using diamond hole saws.

A small hole would be more difficult by hand. In a rigid machine a small hole might succeed by starting the hole in one side, going half way and then turn it over to finish it thru. It's the breaking thru that usually takes out the whole thing, the sudden shock. Then one would want to dress up the edges with a diamond grinder bit that can be found for dramels.

I would practice on some small unwanted pieces. But on the other hand I'd lean more towards moving/changing the brackets.


Drilling Holes

YouTube - Drilling a Glass Fish Tank

YouTube - Drilling an Aquarium

[Badsanta]

Your going to break it anyway, so just smash it and order a new one!!! Oh am I up too late again?

[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.