drillable?

[johnwe]

How do I tell if my tank, which I picked up used, can be drilled or if it is tempered? It is a 110 gallon tank, 48 wide, 18 deep and about 28 tall.

The glass is very, very thick.

[Consigliere]

What are you drilling? Sides, bottom. Huge difference here.

The sides you are almost 100% safe just drilling away and not even looking for the signs of being tempered.

The bottom is another story.

Even old ones are almost always tempered. Google how to tell if glass is tempered to find out some ways to identify tempered glass.

If it is tempered, you are pretty much done. I've heard of some who have managed to drill 1" holes in tempered but obviously the overall success rate is quite low.

[John_Nicholson]

Around here old tanks were almost always drillable, but the new tanks are tempered glass on bottom. Of the 100 or so old tanks that I have had though the years only one was tempered.

-john

[MostlyDiscus]

Lets hear it for the old metaframe slate bottoms. Gawd they were heavy. Had a ton of them back in the 70s. Most newer tanks are temp bottom only. If you try to drill temp it will shatter.

[MostlyDiscus]

Hey, at least I said 70s... LMAO

[Jhhnn]

It comes down to the question of how old is old...

I'm in the process of rehabbing a 75 gal Oceanic reef system, vintage 1992... I found the date on the inside of the top frame when i tore it off to do a partial rebuild, not just a reseal... It's the tank from hell that I never should have bought, but that's another story.

The bottom glass is 5/8" thick, drilled, and obviously not tempered. If the bottom glass of the tank in question is also that thick, then it's probably not tempered, given that the tank footprint is the same. Careful measuring seems in order.

I really don't know when manufacturers started to switch to tempered glass bottoms, but to my knowledge, none of them use tempered glass for the sides, which would be the safest bet for drilling, anyway...

Modern glass working methods allow glass to be drilled or cut, then tempered afterwards, according to the people who supply glass to my employer... so having a drilled pane doesn't mean you can drill another hole in it, at all. Just a little heads-up to potential drillers...

[johnwe]

I don't think I would drill the bottom, the back. Anyone want to guess the age? What size sump would you suggest? I might try to make it myself. I still need to build a stand for this big one. Right now I have two eheim canisters that are rated to cover 80 gals each. Does everyone think a sump is a good idea? I kinda like the idea of hiding all the stuff down there, but I am a little nervous about water issues. This tank will go in my living room.

[Dkarc@Aol.com]

Here is the way I was told if a glass pane is tempered or not....get a pair of polarized sunglasses and pop both lenses out. Put a lense on each side of the glass pane and look through them as you slowly rotate one of the lenses. If you see a pattern in the lenses, it is tempered. If not, its good to drill. Not 100% sure if it works, but ive been told this by 2 different sources now.

-Ryan

[Consigliere]

I don't think I would drill the bottom, the back. Anyone want to guess the age? What size sump would you suggest? I might try to make it myself. I still need to build a stand for this big one. Right now I have two eheim canisters that are rated to cover 80 gals each. Does everyone think a sump is a good idea? I kinda like the idea of hiding all the stuff down there, but I am a little nervous about water issues. This tank will go in my living room.

JOhn,

The back is almost certainly not tempered. You are probably safe to just go ahead. One thing you can check though, is the corners of the pane you are going to drill. If you see a small piece of the corner out off, the pane is tempered.

[johnwe]

Thanks, here's more pics

If the glass chips seems like it can't be tempered right?


http://shortclip.com/fish/glass_chip.jpg
http://shortclip.com/fish/chip.jpg
http://shortclip.com/fish/glass_edge.jpg