need help cutting thicker glass

[tdtreefer]

so ive got an old 55g tank that i took apart, not holding water anymore. i saaw this really nice size tank at my lfs, its 36x12x12. well i have a light for that surprisingly, so why not, and i dont want to spend the 250 they want on the tank when i have glass laying around my house. so i tried it, scored it, i can not break this bast***. it bends and will not break, i dont know what the deal is. i am using a good score and oil. have a square edge and i cant get it to save my life. anyone have experience cutting thicker glass? its only 3/8ths thick. could it be that the glass is old and not even worth risking cutting? or im not scoring it correctly? i made sure i went overr the edges like the directions said. :deadhorse1:

 

[CuzzA]

Typically every pane on a 55 gallon tank is tempered. The strength from tempering is why it's not breaking, but rest assured when it does it will shatter into a million pieces.

It probably didn't shatter from scouring because it was a weak tempering job by the factory.

 

[tdtreefer]

Makes very good sense. The end peice didn't shatter but I guess I'm not willing to pick up all that glqss. I'll just buy the tank. Thanks

 

[Mike_Diako]

Are you using anything under the glass as a lever point? I just made a frag tank out of an old 55g with 3/8" glass as well. It was hard to snap but nothing too bad. I used a small dowel under the glass close to the score line.

 

[CuzzA]

Depending on who made/how old the tank is it may not be tempered. But I know almost every 55 theses days are tempered.

 

[Gorgok]

When i cut up a 75 i used score and tap to get it to break. It was also 3/8", which seems thick for a tempered 55, so it may not be tempered.

With scoring and tapping you hit the glass opposite the score with something (like a hammer) to propagate the break along. You could probably do it without, but the amount of force needed (at least for my full 4' pieces) is more than i could do.

The better you are aligned under the score the better the break will be, but it may never be as straight as a snap, at least i would assume so.

 

[EvenFurther]

The best cuts I get on .25" glass is by scoring, flipping over and tapping, flipping back over, securing the score line at the bench top edge with clamps & 2 x 4. Then, snap the piece off when the opposite section is clamped in place.

I would inspect the glass to determine if its tempered first by following the test instructions with polarized glasses and LCD screen, (something along those lines).

 

[tdtreefer]

It's tempered. Had to test it out. If it was I had no use for it anyway. Tried it in my garage on a sheet. Only a few pieces escapes. But definitely lots of glass

 

[sleepydoc]

kind of impressive to see a piece of tempered glass shatter, isn't it!

 

[tdtreefer]

kind of impressive to see a piece of tempered glass shatter, isn't it!

It's awfully loud. But yes very impressive. Still finding glass in my garage to