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Old 11/30/2013, 03:40 PM   #26
evsalty
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I measured the glass on my Aqueons. The 20l is 5mm just like my rimless is. Being that the 20l is also 12" in height it should not bow enough to be visible without a straight edge placed to the glass. My 40br glass is 6mm yet has bow that is visible without the need for a straight edge. When a straight edge is placed on it vs the rimless there is a big difference in the gap after the center of the bow and the straight edge with the 40br that has a rim having almost 3 times the gap.

I don't know about you guys but that makes me really question how much strength the rim is really giving to the tank.


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Old 12/01/2013, 09:38 AM   #27
Fredfish
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Quote:
Originally Posted by uncleof6 View Post
I get that alot, it seems. However, with 20 something years building small and large rimless tanks, i am my own document; my own source.
...

Some numbers do get thrown around, and often are really not understood either. 3.8 is a common quoted safety factor; the more responsible writers saying that is intended for a tank using a full metal rim. Given the variables in tank building, it is irresponsible to use less than 7.6 sf for a rimless tank, at the hobbyist level or even at moderate experience levels. ...
Thanks for the detailed reply and for providing your background.

I have been poking around the web to try to understand the safety factor calculation and what it means. Things often get repeated and misquoted without understanding the implications.

I did not know that bit about 3.8 = for metal rim and had not seen that posted anywhere.

A few more questions if I may...

Why does the safety factor required for the glass increase with the use of a Eurobrace vs plastic rim? Structurally, the glass Eurobrace should provide far more rigidity than any plastic rim.

How is the width of a Eurobrace calculated? I would think that the principles behind this brace would be similar to structural rigidity in an I beam.

I would also think that the width of a Eurobrace is affected by the span it needs to cover as that would affect the compression forces applied to the brace, but that does not seem to come into play for tanks I have seen.


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Old 12/01/2013, 04:04 PM   #28
koocmada
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Originally Posted by 7808 View Post
in person, the glass did not look thicker or special then my standard 20h glass tank from petco i made into a sump, but i dont think i could tell regular glass apart from tempered, or the price difference, because the price of the marineland tank seemed to go mostly towards the stand and light etc..

everything you guys said makes sense to me, so when i seen this one in the store i was thinking that looks like a de-rimmed normal 20H , what?
It sounds like you want to do this no matter what but you're looking for an overwhelming "do it" from reef central users which probably wont happen. If you want to do it do it, just prepare yourself for the possibility of failure. Prices are starting to come down on some rimless tanks at least. I grabbed a Mr Aqua 17 and the silicone work and quality is amazing. It's not 20L dimensions obviously.


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Old 12/01/2013, 10:35 PM   #29
sleepydoc
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Originally Posted by koocmada View Post
It sounds like you want to do this no matter what but you're looking for an overwhelming "do it" from reef central users which probably wont happen. If you want to do it do it, just prepare yourself for the possibility of failure. Prices are starting to come down on some rimless tanks at least. I grabbed a Mr Aqua 17 and the silicone work and quality is amazing. It's not 20L dimensions obviously.
+1

Safety factor is simply an estimate. If the calculations based on the glass strength and the expected load say it should work with thickness x, you want to use glass thicker than x to accommodate errors in your calculations, variations in the quality/strength of the glass, an extra rock leaning against it, etc. Think of a bridge made of steel. You calculate that it should support 5,000 lbs. Now you're driving a truck that weighs exactly 5,000 lbs. Would you trust driving across it? I hope not!

A couple of other definitions:

Safety - the likelihood that an adverse outcome will not occur based on known factors/information.

Outcome - what actually happens, regardless of precautions that were or were not taken beforehand.

Note that the second does not involve the first, and the first is essentially a probability. Nik Wallenda walked across the Grand Canyon on a tightrope. He got across just fine, but would you call it safe? Also note that safety is a judgment call, based on your tolerance of risk as well as the cost of an adverse outcome.

I'm not qualified to say what a safe design for a rimless tank is. The best person to do that around here is Uncle, and he's given his advice.


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Old 12/03/2013, 02:46 PM   #30
7808
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Quote:
Originally Posted by koocmada View Post
It sounds like you want to do this no matter what but you're looking for an overwhelming "do it" from reef central users which probably wont happen. If you want to do it do it, just prepare yourself for the possibility of failure. Prices are starting to come down on some rimless tanks at least. I grabbed a Mr Aqua 17 and the silicone work and quality is amazing. It's not 20L dimensions obviously.
not really, just a curious mind and a skeptic, when i see a thin glassed unbraced tank produced by a major name in tanks it seems to contridict what i was getting from this thread is all



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Old 01/09/2014, 09:11 AM   #31
TJ_Burton
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Originally Posted by uncleof6 View Post
That assumes that the top edge is actually finished, most are just ragged edges waiting to chop up your hands and arms at the slightest provocation. Eurobracing won't do a thing to solve that issue. In the long run, if you want a rimless tank, go and buy a rimless tank. The tank is the small expense asscociated with this hobby.
Sandpaper...

Come on now, you a DIY hater or something?


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Old 01/09/2014, 10:43 AM   #32
small_polyp
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Originally Posted by uncleof6 View Post

It takes hours searching the internet looking for the answer you want to hear. It only takes a few seconds for your happy pretty tank--to turn into a mess all over your floor.
this quote should be required reading for everyone. Well said sir


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Old 01/09/2014, 01:59 PM   #33
jeromeit
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I've seen it done, but do not trust it. If you're really planning on doing it anyway, consider eurobracing.. or leave it alone and make a cool canopy =]


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Old 01/11/2014, 11:50 AM   #34
barjam
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You are basically fishing for the answer you want to hear. I read a thread just like this the other day that was basically a carbon copy. The guy came back a year later with a follow up that he had to replace the tank because the seam gave out like everyone told him it would.

Just to reiterate the rim on a rimmed tank is a significant portion of it's structure. Removing this will compromise the strength of the tank and will drastically reduce it's life.

If nothing else if you do decide to remove the trim please update this thread when it fails to serve as a warning to others!


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Old 01/11/2014, 02:04 PM   #35
mussel and hate
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So much bad information here.

Quote:
Originally Posted by jong11 View Post
Bad idea. It's not designed to be rimless.
Based on exactly what?

Quote:
Originally Posted by jsjonesrdh View Post
Glass is too thin
as above.

Quote:
Originally Posted by uncleof6 View Post
The rim on the tank is a engineered part of how the tank stays together. The tank is not designed to be filled with water, without the rim. In other words, the tank is not engineered to be a rimless tank. Pulling the rim off is asking for a flood all over you living room. I am aware that many uninformed people remove the rims on these tanks, and much larger tanks..............they must like living dangerously.

It takes hours searching the internet looking for the answer you want to hear. It only takes a few seconds for your happy pretty tank--to turn into a mess all over your floor.
Well that's some ****-poor engineering then as every plastic rimmed tank I've owned (and I've owned quite a few) have suffered rim failure at the corners eventually. By this logic one must avoid buying any plastic rimmed tank as they're all ticking time bombs.

I have a 20 year old 20 gallon that has been rimless for over a decade. The glass looks to be 3/16" thick. I broke the backpane derimming and replaced it with window glass of the same thickness and RTV construction adhaesive. My floors are still dry, fish and corals are healthy.

A 20 long is under less pressure than a standard 20 and should be fine.

For rim removal I used a razor knife and a 6" drywall knife. I got cocky and rushed the last bit causing a break, go slow and be patient.


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Old 10/25/2021, 11:00 PM   #36
jjmccloud2011
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Originally Posted by nemosworld View Post
The 20 long will be fine, the plastic trim is just to hide the imperfection of the glass.
if it had a center brace i might be worried, but it does not.
That is horrible advice �� Is that what you think that plastic trim piece is really there for??? To hide the imperfections ���� Don't let its thin and cheap looking design fool you cause I promise it does more then hide some imperfections! Aside from that most 20g longs will be fine as long as it doesn't bow out when filled, different manufacturers and tanks have different pieces of glass , if it doesn't bow chances are it'll be just fine. Myself when I do this to 20g long or high I will usually silicone either a glass brace across the top, either in the middle or a strip on each side of the tank just to be safe and help relief some stress to cover silicone joints but in most cases on a 20 long thats overkill even


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