From: charleyb@gr.hp.com (Charley Bay (Contract))
Subject: Re: Cutting Hole in Tempered Glass
Date: Fri, 20 Oct 1995 17:48:14 GMT
: : THE PROSECUTOR (utpennington@cc.memphis.edu) wrote:
: : : i have been told by many people on this group that drilling tempered
: : : glass is suicide as it will just shatter. however, local glass
: : : companies, (who i would get to cut the hole
: : : for me) insist that they can CUT it with a special glass cutter with
: : : no problem.
: patrick timlin (ptimlin@lynx.dac.neu.edu) then said:
: : If they guarantee the work, then go for it, you have nothing to loose.
Right. Make them guarantee the work unless it's a cheap tank. (I
bet they'll charge extra for the "insurance". In my town, none of
the cutters will guarantee a tempered glass cut.
Finally, Kristi Bittner (kristi@sc.hp.com) said:
: Also, doesn't it take out the temper, if it's been cut? Do they
: re-temper it for you? (Or am I out in left field?)
No. Tempering the glass is heating and cooling. Simply by
cutting it doesn't remove the fact that what remains was heated
and cooled.
I've drilled tanks, and had my tanks drilled. However, I'm now
reformed: I wouldn't do it again and I wouldn't recommend it. :^>
Tempering glass is like tempering most metals: Heat the item up
and cool it off to get a more "crystaline" formation, or a more
complete molecular binding (the heat provides the free energy
to weaken bonds so they can re-attach more strongly).
You can temper to varying degrees: Heating iron to red-hot then
cooling, blue-hot then cooling, or white-hot then cooling will
give varying tempers to the item.
For metals, you usually know what you want: A lawn-mower blade
has a weak temper: It holds a little edge, but is not that strong.
However, the blade doesn't shatter when you hit a rock: it gets
a ding, and you go sharpen it again. LESS-TEMPERED MEANS SOFTER
AND WEAKER. On the other end of the spectrum, metal files for
grinding are VERY highly tempered. It's tough to wear down the
edge, and knives made from these metal files hold an amazing edge
(I have some I've made). However, these knives are also very brittle
and can shatter easily. MORE-TEMPERED MEANS HARDER AND STRONGER.
There's a guy in town that I'm good friends with that has been
in the glass/optics industry for decades. He has several glass
manufacturing patents, and has been CEO of several large glass/optics
manufacturing companies. After talking with him, I would never
drill my tanks again (especially tempered glass).
Drilling glass, no matter how well done, introduces micro-fractures
that grow with time. Recall the cracked car windshield: The cracks
grow with time. Of course, a car windshield experiences lots of
motion and vibration to accelerate the cracking process; On the
other hand, the bottoms of our tanks are ALWAYS under terrific
water pressure, which doesn't help any either.
Once you drill and introduce those micro-fractures, they are there
and will grow forever. You can't stop them. Someday, it will
grow enough to weaken the glass and the tank will leak or break.
It's only a matter of time. Also, ALL CUTS introduce
these micro-fractures; Nobody cuts glass, because they can't.
Everbody grinds it, even if they are grinding a very small hole.
With tempered tanks, it's worse. The micro-fractures grow faster
because the tank usually relies more on the stronger silicon
bonds from the tempered pane, which are completely gone when
a crack is introduced. Your tank will take less time to
fracture.
I have a 180 gallon tank with two drilled holes. I wish they
weren't there. The tank is fine and I have no horror stories,
but there is a greater peace-of-mind knowing that in a worst-case
scenario, all the water would stay in the 6'x2'x2' box because
there are no holes.
Despite the potential convenience of a drilled bottom, I will never
drill my tanks again. Hanging over-flow filter boxes and water
returns are just fine, and are far safer.
--
--charley #include
charleyb@gr.hp.com -or- charley@agrostis.nrel.colostate.edu
From: boheggus@usa.pipeline.com(Josh)
Newsgroups: rec.aquaria.tech
Subject: Re: OverFlow Box
Date: 2 Aug 1996 17:15:56 GMT
On Aug 01, 1996 16:01:49 in article , 'lnorris@ionet.net
(Larry Norris)' wrote:
>I am in the process of designing out a 75 gal. aquarium. I am an avid
>DIY'er and I'm planning on building just about everything except the
>tank and the live rock (but I'm open to suggestions). :)
>
>In any case, I'm going to use a sump for my skimmer and any other
>devices I want to put down there, and was wondering if anyone had any
>opinions on an overflow box vs. an overflow hole/pipe.
>BTW, I'm planning on using gravity to feed the sump, and two
>powerheads in the sump, one to feed my skimmer and one for return.
>
>My reservations are to both methods are;
>1. Drilling a hole in a perfectly good tank. This and having a
>non-adjustable and possibly low water level all the time.
I kicked this idea around when I set up my 125. I called around to several
glass shops (this is one job I won't try myself) and while a couple of them
agreed to do it, they wouldn't guarantee it. In other words, if the tank
broke while they were drilling it I was SOL. This and the fact that
drilling a tank will void the warranty made me decide against this option.
>2. Siphon on the overflow neck being broken and water all over my
>living room floor. That and the resultant non-too-happy wife..
Been there, got yelled at for that , though not because the siphon
broke. I run three overflow boxes on two different tanks and the siphon has
never broken in the several years I've been using this technique. My
problem has been with snails going through the overflow and getting stuck
at the gate valve in the line to the sump. The trick to maintaining the
siphon integrity is maximizing the flow through the U-tube. As long as the
flow is at around 200-250 GPH, the water moves fast enough so that air
bubbles don't accumulate, IME. Keep the flow rate in mind when you choose
the powerhead for the sump return (I'd recommend a Rio). There are other
tricks like attaching the venturi inlet of a powerhead to the peak of the
U-tube so that any bubbles that do accumulate are sucked out but I've never
tried it. Good luck!
Josh
-Ban anchors, not reef tanks!
From: J Hefley
Newsgroups: rec.aquaria.marine.reefs
Subject: Re: Drilling My New Reef Tank
Date: Fri, 04 Oct 1996 13:34:48 -0500
Jason Pook wrote:
>
> I am currently planning to set up a new reef tank and have aquired a
> new tank 48 x 15 x 18 and I would appreciate some advice about the
> safest way to drill glass to install a way to drain water to a sump
>
> Can the tank be drilled at the top to allow water can drain to the
> sump ratther than at the bottom and fitting a corner wier box?
>
Drilling a tank isn't really a DIY job IMHO, goto a glass shop and have
them do it for a nominal fee (+/- $15 US) they have all the skills and
tools necessary for the job. Also of course be sure that you don't have
a tempered glass tank as these are not drillable. You can drill either
the sides or the bottom, if you drill the sides you will need a bulkhead
I would go for 1.5" or larger. Another option is a overflow that hangs
on the back of the tank.
Good luck.
Jason
From: pRpLe
Newsgroups: rec.aquaria.marine.reefs
Subject: Re: Drilling My New Reef Tank
Date: 10 Oct 1996 01:24:01 -0700
Jason Pook wrote:
: I am currently planning to set up a new reef tank and have aquired a
: new tank 48 x 15 x 18 and I would appreciate some advice about the
: safest way to drill glass to install a way to drain water to a sump
: Can the tank be drilled at the top to allow water can drain to the
: sump ratther than at the bottom and fitting a corner wier box?
: Many Thanks
: jpook@glades.demon.co.uk
Well, unless you have the proper tools (glass drills are WICKED expensive)
and LOTS of experience drilling glass, I have to tell you to take the tank
to a professional. Messing up on a job like this can cost a LOT of money.
Good luck
Rob
--
jrm@primenet.com
All opinions expressed are exactly that, OPINIONS.
Taking them as anything other than that exhibits a
great lack of common sense, and the author(s) shall
not, in any way, feel bad if you, or anyone you know
make a total fool of yourself by not conducting
extensive scientific research before taking any action(s)
that may have been prescribed in the text above. :P~~
