Tempered versus Non Tempered

[Tacticalbaton]

I have looked up the word tempered glass on these forums and really have not been able to find much info. I do understand that tempered is stronger but at the same time from what I understand is that you can not drill it after. Most tanks from my understanding are drilled (bottom piece) and then tempered. If I am drilling holes in the wall does that wall require to be tempered after? I.e.: cut the glass….temper then assemble tank. What I am really looking at is to make the rear piece of glass two inches shorter in height in comparison to the front and both sides. Lay a set of acrylic comb teeth to cover the last two inches into a trough at the back. Does this back panel have to be tempered or even if you are drilling holes in the rear does the glass have to be tempered? Next question what is the process for tempering glass and why can’t you drill it after?

 

[J.russell]

The bottom is tempered because of all the weight sitting on it. The sides do not have to be tempered even after you drill it.

 

[hllywd]

Not all tanks are tempered on the bottom. I have a 90 that I drilled 4 - 45mm holes in the bottom with ease. It wouldn't be unheard of for the back front and sides to be tempered too, though unlikely. If you drill the back it does no need to be tempered. Tempering is mainly for added strength and manufacturers may use thinner glass if its tempered. The point is you need to verify before you drill.

To give an idea how tough tempered glass is I have witnessed vehicle windows being struck multiple times with the pick end of a fire axe and not breaking. On the other hand I have also seen a piece of spark plug ceramic the size of a pencil eraser tossed lightly at a tempered vehicle window and it shattered...

HTH
Tim

 

[8BALL_99]

Ok lets see. No you don't have to temper the glass after you drill it.. Bottoms on tanks are tempered most of the time cause tempered glass is five times stonger and much stronger against shock. IE a peice of live fall over.. The down side is the Edge of tempered glass is very weak.. You can hit a tempered panel in the middle with a hammer and not break it, But if you tap the edge with one it will probably shatter. The back wall of my tank is also tempered along with the bottom because I have external overflows and the back wall has notches cut for them.. Tempering the panel just makes it stonger.

People have done pretty much what your talking about.. But they notch out the back panel not just cut it short.. The biggest problem I see with what you want to do is you would basicly be making a rimless tank. So you would have to make the panels thicker. But no reason why you couldnt' build it this way.

The process for them tempering glass is they heat it then rapidly cool it. VS non tempered it is alowed to cool slowly. From what I understand it causes the molecules in the glass to all push against each other thats what addes the strength. But if you remove some IE chip the edge. The its like pulling a brick from the bottom of the stack.. The one above falls then the one above that ect ect.. Thats why tempered glass Pops and breaks with such force. All that caged up energy is released all at once.

 

[funman1]

Here's a 30 Gallon tank with tempered sides and NOT a tempered bottom?!?!?!

http://reefcentral.com/forums/showthread.php?s=&threadid=1479869

 

[8BALL_99]

<a href=showthread.php?s=&postid=13477247#post13477247 target=_blank>Originally posted</a> by funman1
Here's a 30 Gallon tank with tempered sides and NOT a tempered bottom?!?!?!

http://reefcentral.com/forums/showthread.php?s=&threadid=1479869

That is weird. I've seen all the panels tempered before, But I've never seen all of them except the bottom. Did is scare the crap out of you when it popped? lol Once I drilled the side of a 29 gallon that was tempered. It sounded like a shotgun.. Scared the living crap out of me. Some seem louder then others.. Not sure why.

 

[mojo~]

Tempering really strengthens the glass. It is the process of heating ht glass up slowly and cooling it quickly storing the kinetic energy in the glass. Once tempered it cannot be drilled. I worked a glass plant for 5 years where we tempered glass for hte automotive industry. Tempered is way stronger but tap it in the right place and it will shatter everywhere. there wont be a little crack or chip on tempered glass it will shatter.

 

[cloakerpoked]

To reiterate what bball said, if you cut 2" out of the entire panel, you can't have a rim anymore. If you're building the tank from scratch, this isn't a problem, but if you are modifying a manufactered tank, it would be. The outward stress on that panel then lies totally on the silicone holding the panel in place, and that is risky too. With a bigger panel, you have more surface to adhere to, therefore a stronger bond. If you look on youtube and search for tempered glass drilling you can see what happens when you try to drill the tank through tempered glass.

Maybe that one tank had a much thicker bottom panel than sides? (i.e. a half in panel of glass on a 30 would be overkill to a crazy degree.)

Does anyone know, does tempered glass resist scratching any better? I know my windshield doesn't seem to...I scratched it all one day with an ice scraper and its really screwed up now.

 

[funman1]

Yeah it scares the crap out of me, I have had it happen a few times.

<a href=showthread.php?s=&postid=13479434#post13479434 target=_blank>Originally posted</a> by cloakerpoked
Does anyone know, does tempered glass resist scratching any better? I know my windshield doesn't seem to...I scratched it all one day with an ice scraper and its really screwed up now.

Your windshield is not tempered.
If it was when a rock put a chip in it it would explode and you would not be able to see of of it. Windshields are laminated with plastic snadwiched in between 2 sheets of glass.

All the other glass on your car is tempered for saftey

 

[BeanAnimal]

Not only that, but if your windshield was tempered, it would turn your head to mush in an accident. The fact that they break easy is a safety feature.

 

[cloakerpoked]

That makes sense...does anyone know if tempered glass resists scratching more/less or the same as regular glass?

 

[Reefun]

I don't know about scratching but it is a lot harder to drill until it goes POP. I was trying to drill a 10gal I didn't know had tempered glass. I couldn't figure out why it was taking so long to drill through and then It popped and I new why

 

[mojo~]

scratches the same your windshield is laminated. IT is actually two pieces of glass with a thin piece of vinyl between them. It is then sent through a infared oven the heats it up to about 400 degrees to make it tacky then the glass goes into a huge vessel that puts under aprox 200 psi and about 450 degrees. This heats up the vinyl and pushes all the air bubbles put of the glass. This if the glass breaks it does blow up. it will keep the glass in one piece for the most part.