ceramic heat lamp cracking tempered glass?

[Mizzerat]

So my roomate works at a glass shop (house & car), so rather than buy a terrarium, he cut the glass for me and we built one. We used 5mm tempered glass, I thought that would be fine with the heat on the side, and it was for a number of months, but today I woke up to this..


Anyone experience this before on a regular or home-made tank? I'm honestly surprised that the element caused tempered glass to crack. Its a 60w ceramic btw.

So yeah.. big crack is bad news, so I took one last picture of Dr. Girlfriend looking out the window of her burrow.

And rehoused her in here until I can get her some nicer accommodations.

 

[journeys and scorpions]

Yeah...the glas of terrariums are to thin for this heat. U must heat from the inside! And this installation is not difficult... you can do it simple with much more heat and
efficiency as heating from the outside ;-)!

 

[wodesorel]

The glass can overheat if the bulb is placed too closely. It's not cooking quality glass, and a regular incandescent bulb can easily reach 400 degrees - I've heard the ceramics get hotter. Any little bubble or imperfection that overheats can cause the glass to fail and crack. For safety, there should be a good air gap of 6-8 or more inches between the bulb and the glass. Adding water to the tank can also trigger cracking due to the drastic temperature difference between hot glass and even warmish water. I've always used heat bulbs over metal screen lids, or aimed through the side at a distance of around 12 inches.